Fuel pump/starting problem for the electricians and experts

[azale]

This is my first post here but I’ve been searching for an answer to this problem for at least 1 week, 2 hours/day all over the internet. Other people have had the problem but there are no answers . . . are you ready?

We just bought a 1994 525i with 191,000, in great shape, meticulously maintained by an engineer. My wife drives 15 minutes to church and it sits for about 15 minutes. She then tries to start it again and it turns over (sounds like good compression) but it doesn’t fire up. A quick diagnosis: no fuel pump noise, bad fuel pump. I buy a used fuel pump off eBay while I’m waiting for my dad to loan me his volt meter. The volt meter says no power is going to the pump (fuse 23). Because I don’t know which relay is for the fuel pump I checked every relay under the hood and only 2 refuse to snap: one large relay with about 8 pins in the driver side fuse box (across from the crash alarm relay, separated by the LKM I think), and a five pin relay by the ECU – yes, the DME or the main relay. I buy a new DME and still no power to the fuel pump. I finally find the fuel pump relay by testing for resistance to the hot side of fuel pump fuse, and replace that relay (even though it was snapping). Still nothing.

Jumped the fuel pump relay with fuse 23 in its proper place and guess what I hear . . . the fuel pump in the trunk and the injectors (I think) in the engine compartment) which makes sense according to the wiring diagrams (the fuel pump relay runs both). All the contacts in the relay plug are working fine: 30 is hot all the time, 87 grounds out after going through fuse 23, the fuel pump, and the injectors. When the key is turned, 86 is hot and is sending 12 volts through contact 85 which grounds out without a problem. Still, with the relay in place no power goes to the fuse.

When I turn the engine to try to start the car *and* jump the relay, the pump runs fine but the engine still won’t start. I don’t smell a lot of gas coming out of the exhaust but I’m afraid I will flood the engine if I keep running the pump/injectors w/o the relay.

This “power-to-the-relay-no-power-to-the-fuse-unless-I-jump-it” is giving me nightmares. I just doesn’t make any sense.

There are no error codes (when I read the codes, the light blinks for .5 sec, off for 2.5, on for 2.5 and off for 2.5 in a continuous cycle).

I’ve heard it could be the crankshaft position sensor but I also heard that would give me a code.

Any ideas? What is that big relay opposite the crash alarm relay? Tonight I will test the sensor if I can find it and check for spark and fuel pressure. I have TIS disks coming in the mail. I need an answer before I run out of money. Any help is much appreciated.

[632 Regal]

Good details in your post, you will have to wait for the electrical department to come back from lunch...lol. Bet you get an answer here.

Lake orion huh? Thats just east of me.

[ryan roopnarine]

did you ever replace the DME relay in all of this?

[azale]

yes, I replaced the DME with a new unit $17, fuel pump relay was $15.

I also replaced the fuse in my dad's volt meter when measuring the amps going through the relay . . . there are at least five amps moving through just fine :)

Bavarian BMW in Utica/Shelby Township want $114 to look at it but I have to tow it there.
The crankshaft sensor will be $95 if I need it.

[Garlic Breath]

Fuel check valve.

http://www.bimmer.info/forum/showthread.php?t=14388


It fixed the no start problem with my car. The dealer said it would not work on my car but what the hell do they know. Easy, cheap and fast fix.

[azale]

I can try it but I don't have a 'hard [when] hot' start problem. It's 'no start' and it's electrical I think. But to test my theory, if I take off the fuel line before the injectors, and there is gas and pressure, it is not the check valve right? And if I jump the pump relay or fuse and gas is flowing that means there are no clogs.

I will be extremely careful to direct all the extra gas into a bottle and keep the garage ventilated.

[DanDombrowski]

I read somewhere a writeup on checking fuel pressure by doing that, and the guy ran the fuel into a 2 liter bottle. If you've ever sprayed a part with throttle body cleaner (or brake cleaner) and had the excess run into a plastic cup, you'll see why this makes me wary. Not saying its dangerous, but I think petroleum based products don't like plastic so much. In any event, mabye drain the gas into a glass bottle when you check for fuel?

Now, as far as your electrical problem...



When the key is turned, 86 is hot and is sending 12 volts through contact 85 which grounds out without a problem.

I don't like the way this sounds. I might be misinterpreting what you're saying, but nothing at 12V should short directly to ground.

You said you replaced the DME for $17, I assume you mean the DME relay. I've never really had a need to run a test to see if the DME had power by checking voltage, I guess if you're checking current running to it that would tell you (if you have the multimeter connected correctly). I would check for spark by pulling a spark plug. If the DME doesn't have power (or doesn't have all of its info, i.e. no cps, etc) it won't fire the plugs and injectors, right? Someone else can back me up or refute that one.

I would think that if the CPS were bad, or another sensor was keeping the DME from wanting the engine to run, you would get a check engine light. You never know though, the PO could have removed the bulb.

Have a check at the fuel flow rate, but I don't think thats it. If you look at the procedure for replacing the fuel filter, it says "pull the fuel pump fuse and let the car run till it stalls". You would think that if the system has pressure when you shut the engine off, and then go to restart it (without the fuel pump turning on), it should at least run and then die (not sure on that one either).

Also, check for spark and let us know whats up with that. Thats about the extent of my electrical expertise I can give you for now.

[azale]

The contacts I was referencing were specifically for the fuel pump relay (although the DME relay plug tests correctly as well, the only difference there is where the DME relay contacts 87 go, there are 2 87s, five prongs in all)

on the fuel pump relay, contact 86 comes from the DME relay or some type of switch (see here http://www.carsoft.ru/avtorepair/bmw_e34/1210.10/index.html) and 85 goes to the actual DME control unit. I just tested that contact 85 was grounded (I assume after it goes through the DME control unit.

The check engine light is definitely working but I may be reading the codes incorrectly, please see my first post. Also, when I press the reset button under the tach and trun the key and then release the button one line says "CODE.NR 0000" which I assume means no codes??

Tonight I will revert to the troubleshooting I use on my 1980 johne deere snowmobile but I fear the problem is deep inside the electronics.

[stevebuk]

Sounds like you should check the crank position sensor.

I currently have the same problem with my 520i, it was intermitent but now will not fire, cranks fine, fuel pump runs etc.

I've followed the cps cable from the sensor to up near the thermostat housing and behind the oil filter housing but then the cable disappears beneath the inlet manifold / near the alternator and so far I can't locate the connector. Perhaps it's easier from underneath the car?? Or maybe it's easier to check the signal at the ECU plug? anyone know the pin number?

[Garlic Breath]

Does it start when sitting overnight?

[azale]

Does your fuel pump run when your turn the key? Mine doesn't.

Can you give me a clue where the CPS is? front of engine I hear. high/low? left right? Have you tested your sensor for resistance? everyone says look for 600 to 800 ohms, more than that and you need to get a new one.

Garlic, No, it doesn't ever start (for 2 weeks now, I'm afraid the battery is going to give out soon. BTW I removed the interior lighting fuse but I don't think that should affect anything.

[DanDombrowski]

The fuel pump should run for a few seconds when you turn the key on, then shut off.

I read over those diagrams, I don't think 85 goes to ground. I think its saying that when it has power (12V) from 86 AND 85, then it routes power from the battery to 87, which is the fuel pump. So 85 should not go to ground, but I could be wrong.

See if you can actually test one of the leads for the DME for voltage to see if its turning on, and do a fuel pressure/flow check.

[stevebuk]

I can't hear the pump when I turn on the ignition but I can if I bridge the relay connection - under normal conditions it runs very briefly to prime the system but then switches off until the engine fires.

CPS is about 10 o'clock at the side of the crankshaft pulley close to the teeth of the pulley, there's a picture on this forum somewhere but can't locate it at the moment. If there aren't any pulses from the CPS the car will not start so it's the logical thing to check after the fuel pump - just wish I could find the connector!!

[Garlic Breath]

Sorry I misunderstood your message. I didn't realize that you couldn't start the car at all after the short trip to church. Didn't mean to muddy the water. Good Luck!

[azale]

stevebuk, maybe we do have the same problem. http://www.carsoft.ru/avtorepair/bmw_e34/1210.10/index.html says that pins 78, 79 and 82 are for the crankshaft sensor and pin 52 may be important as well. But I don't know where that plug is. Is it the DME harness inside the passenger-side box? And what are we looking for resistance/votage between + and - or resistance to the ground? I'll mess around with it tonight.

Dan, I've tested leads to the DME successfully and it should be/is switching. I'll still check the pressure flow.

garlic, thanks for your help anyway.

[ryan roopnarine]

look at the front of the cylinder head. the cps sensor body is attached down near where timing marks would normally be. a wire runs up and along the front of the cylinder head. a plastic "retainer" held on with circlip type fastners is on the front of the cyl head too, the cable runs under there. follow it back under the intake manifold . the connector you are trying to get to may or may not be resting in a mounting bracket.

[stevebuk]

If you use a jumper lead to connect the fuel pump relay pins 30 & 87 (6 and 2) on the socket the pump should run continuously, if the car still doesn't star it will point to a different problem. You should hear the fuel hissing through the pressure regulator in the injector rail and near the wheel arch under the fuel filler.

I'm going to have another look under the inlet manifold tomorrow to see if I can locate the CPS connector, the CPS produces pulses around 0.5v if it's working.

[Kalevera]

Azale:

First, welcome. Congrats on the car, they're lots of fun.

Now, for some criticism. I'll be nice, but it still needs to be said:

Despite the diagnosis of fuses and relays, you still haven't determined to which necessary element of engine operation the problem can be attributed. An engine (even a VaNOS M50) requires fuel, air, and a spark to work. The first thing to do would be to determine if the fuel is being delivered. Playing around with relays is nice, but it doesn't help much. You can strain your ears as much as you want, but it still won't tell you much. Heck, the gas tank could have a dent in it, thereby messing with the fuel level sender -- car thinks it has gas, you think it has gas, but it doesn't. Listening won't tell you that. Get a fuel pressure gauge on the rail and see if you have fuel with the key in the run position. No fuel? Hey, you've just narrowed the scope of possible malfunctioning elements by 50%.

Do that and then tell us what you've got. People saying, "I think it's the CPS" based on what you've told us already (unless I missed some critical element, which is possible) is just a waste of your time. Randomly replacing parts is an even bigger waste of time (and money).

By the way, how do you know that the car is in great shape?

best, whit

[azale]

Lowell: Thank you, I do like the car: almost as much as my wife does.

Thank you for being kind with the criticism, I get enough rejection from my BMW right now.

For a little more background: I had it towed to my friend's garage. I live in an apt and my dad's garage already had a disabled vehicle. Because I never heard the pump, I assumed it would be an easy fix with minimal tools--a job that could easily be performed inside my buddy’s garage. Because of the lack of tools, I have been looking for an easy fix, and everyone online is talking about the DME relay, the fuel pump relay, and the crankshaft sensor. When I checked the fuel pump relay, things didn’t add up so that caught my attention.

Now, I am following the bottom-up approach. Using minimal tools, I broke the seal on the fuel rail and gas squirted out all over the place. Fuel in rail and pressurized – check. Plenty of air is coming out of the tailpipe so air must be getting in there. Air – check.

The next tests were performed with no help, while the battery was losing power. I pulled one plug: it was dry and it didn’t look like it was sparking (from inside the car), but the plug wasn’t touching a grounded bolt (which I have been told to do). Then I checked for voltage going into the coil and didn’t get any, but it is possible that when I taped the connections to the frame I wasn’t getting a good connection.

I will check tomorrow with some help but I assume there is no spark and it’s possible that the injectors aren’t pushing fuel. The gas tank has no significant dents .

I say good shape, you may say the car looks great, almost no rust, the interior is in great shape, strong engine, smooth shifting, new timing chain, new tires, new suspension, new steering linkages, and I could perform open-heart surgery in the engine compartment if I had a willing patient.

Stevebuk, I looked for the CPS connector with about as much luck.

Does anyone know what pins in the DME harness are for the CPS? I read they were 78, 79, and 82 was ground. Well, my harness doesn’t even have wiring in socket 79. The way things are going with this job, I’m not surprised.

[Kalevera]

Excellent. Now we're getting somewhere.

Checking for spark on the M50 is a bit tougher than the earlier engines because it uses coil packs. Why was the timing chain changed? My thinking here is that the engine may be out of time -- I've never heard of anyone doing a timing chain on an M50, esp TU, without extenuating circumstances.

Before monkeying around with anything else: pull all of the coil packs and inspect them for leaking ("caramel candy") insulation. Once they leak, they're bad -- they'll fry out the DME (not the relay -- the final stage inside the DME itself).

The M50TU has two sensors of import that relate to timing: a crank and a cam position sensor. The crank sensor is located on the top header side of the vibration dampener and reads the ring gear. Cam is on the side of the head tucked behind the VaNOS solenoid.

Please don't be frustrated; we'll get it worked out for you. I didn't mean to come off as a jerk in the earlier post -- I was impressed with the information, just believe that there're better ways to approach the diagnosis.

best, whit

[genphreak]

Excellent. Now we're getting somewhere. Please don't be frustrated; we'll get it worked out for you. I didn't mean to come off as a jerk in the earlier post -- I was impressed with the information, just believe that there're better ways to approach the diagnosis.

best, whitClass sleuthing Whit, I'm sure I am not the only one following this chase... I'll put an early bet on with you and say some of those those coils are bad...

Seriously, with a BeMtroubleuw the devil is often in the detail... so this thread provides a clear lesson for many: Azale (good work on your posts mate) made a huge effort to explain things clearly and probably has a solution now. We should all try to take as much care when posting, to be specific and explain the context within which we describe our actions/deductions. It encourages good minds like Whit to pipe-up and help out, so before you know it the fault is found (exactly as Whit has gone to great lengths to do here).

If you don't take the effort to explain yourself the solution can be harder than pulling teeth.. which won't help anyone.

I hope this optimism doesn't jinx Azale in fixing it now...

[Bill R.]

cps... I would first check again for spark, having somebody help while you ground the coil and the plug electrode and crank it to check for spark, if your not getting spark then i would check the cps, if you are getting spark and you already have fuel pressure then i would check the camshaft sensor which triggers the injectors.http://www.bimmer.info/%7Ebill/M50cps.jpg






Lowell: Thank you, I do like the car: almost as much as my wife does.

Thank you for being kind with the criticism, I get enough rejection from my BMW right now.

For a little more background: I had it towed to my friend's garage. I live in an apt and my dad's garage already had a disabled vehicle. Because I never heard the pump, I assumed it would be an easy fix with minimal tools--a job that could easily be performed inside my buddy’s garage. Because of the lack of tools, I have been looking for an easy fix, and everyone online is talking about the DME relay, the fuel pump relay, and the crankshaft sensor. When I checked the fuel pump relay, things didn’t add up so that caught my attention.

Now, I am following the bottom-up approach. Using minimal tools, I broke the seal on the fuel rail and gas squirted out all over the place. Fuel in rail and pressurized – check. Plenty of air is coming out of the tailpipe so air must be getting in there. Air – check.

The next tests were performed with no help, while the battery was losing power. I pulled one plug: it was dry and it didn’t look like it was sparking (from inside the car), but the plug wasn’t touching a grounded bolt (which I have been told to do). Then I checked for voltage going into the coil and didn’t get any, but it is possible that when I taped the connections to the frame I wasn’t getting a good connection.

I will check tomorrow with some help but I assume there is no spark and it’s possible that the injectors aren’t pushing fuel. The gas tank has no significant dents .

I say good shape, you may say the car looks great, almost no rust, the interior is in great shape, strong engine, smooth shifting, new timing chain, new tires, new suspension, new steering linkages, and I could perform open-heart surgery in the engine compartment if I had a willing patient.

Stevebuk, I looked for the CPS connector with about as much luck.

Does anyone know what pins in the DME harness are for the CPS? I read they were 78, 79, and 82 was ground. Well, my harness doesn’t even have wiring in socket 79. The way things are going with this job, I’m not surprised.

[azale]

Lowell: the timing chain was replaced as a result of the previous owner’s meticulous care for his car, the fact that it had 190,000 miles, and his vocation as an engineer at ZF Sachs (just for the record, he has an ‘80s Jaguar Vanden Plas in better shape than the 525). He also replaced the main and upper tensioners. Up until now, the car had been driving great, plenty of power, no complaints. I was driving a car when the timing chain skipped a gear and it was . . . obvious, but the car had given me 240,000 miles so I wasn’t as bummed as I am right now. It was actually my dad’s car and his ‘bummedness’ was a different story.

I will inspect the coil packs tonight. Where do I look for the leakage, around the outside or down into the hose that leads to the plug? Do the coils snap off the hose? If one coil leaked, do I need a new DME?

Please accept my pre-apology for the next sentences. I am sorry that I haven’t received my repair manual and therefore am unable to identify certain features on my car. The manual is literally in the mail. 1. Please explain ‘TU.’ 2. I forgot to mention this but last night I was looking at the ‘hot/jump nut’ under the hood that comes from the battery. From there I see a footlong thick red cable going to what looks like a solenoid on the back of the engine (but the solenoid main contact is pointing toward the front bumper and the rest of the unit is toward the firewall). The cable is frayed/split. I assume this isn’t a big problem (yet) because the insulation doesn’t look burnt. I can’t imagine the cable fried because I think the fusible link would bite the bullet first. Let me know.

Genphreak, I also hope your optimism doesn’t jinx me, but it is refreshing.

Bill, thanks for the diagram. I will check for resistance between 16 and 43 tonight but what about the camshaft sensor? Am I checking for resistance between 17 and ground or 17 and 7?

You guys have all been a big help thus far. Thanks.

[Kalevera]

Lol, no worries man. No need for apologies, either. There are no stupid questions around here, so ask away (but a search is always a good idea ;) ).

Someone has a picture of a leaking coil pack. I know I have one, too, but I can't seem to find it right now. The insulation has a caramel color to it. None should be visible when inspecting it. It usually oozes out by the plates. Pull the plastic cover, undo the 2 x 8 mm (or are they 10? I forget) on a pack, use a flat blade screwdriver to disconnect the harness connector, and pull the coil out. While you're at it, inspect the plug holes for oil -- a leaky valve cover gasket will cause oil to seep in there, which has the potential to wreck the lead and coil. Only worry about the leads if they're wet with oil -- just inspect the packs.

"TU" refers to the VaNOS (variable valve timing, german-ified) version of the M50. Mid production run (91, 92) 525s were delivered with the non-vanos version, which has a different head and a few other items.

The solenoid you're seeing is for the starter. It needs a heavy gauge wire, direct from that terminal and from the battery, for all of the obvious reasons.

Good luck!

best, whit

[azale]

I pulled the first two coils off and here’s what I found:
first coil (closest to the front bumper)
http://www.andyzale.com/album/albums/userpics/10002/normal_coilleak1.jpg
second coil
http://www.andyzale.com/album/albums/userpics/10002/normal_coilleak.jpg
The insulation sure doesn't taste like caramel :)

I also checked the resistance between DME harness contacts 43 and 16 per Bill R’s diagram: a little more than 500,000 ohms. I found 10,000 ohms between contacts 7 and 17, but I don’t know if that is the proper procedure for testing the camshaft sensor resistance. Is my sensor hosed or is there a better test?

So 'VaNOS m50' and 'm50TU' is the same engine and 'VaNOS m50TU' is redundant, right?

It looked like a starter solenoid but I though the starter was on the front side of the engine. Is the solenoid bolted to the starter?

I would have sent this message last night but my connection is slow as molasses. I use my blackberry as a GPRS cellular modem (unlimited data usage through Tmobile) but for some reason I can’t access google. That’s usually not a big deal but bimmer.info gets ads from some type of google syndication site. My computer downloads all the source code then waits and waits for the ads. But that’s a problem for another message board.

[stevebuk]

I think your coils should be fine, the one nearest the windscreen is generally prone to some rusty marks on its exterior.

I've made great progress with mine, I connected my scope to the ECU socket and both the crankshaft and camshaft sensors were producing pulses. I found the problem was no supply to pins 48 and 54 from the DME main relay, removing its white plastic cover and pressing the actuator allowed me to start the car. The supply to the relay is being switched by the ignition but the coil is open circuit. Off to the stealer tomorrow morning to get a new relay.

Don't know if you've looked at this site but great info on pin outs and wiring diagrams etc.

http://www.carsoft.ru/avtorepair/bmw_e34/E34.html

Steve

[azale]

That's not rust; its coil insulation.

Did you have to remove the intake manifold?

Tell me more about your scope. Does it send power through the sensor while you crank the engine?

[stevebuk]

The coils are potted in a small amount of epoxy, it's quite normal to see a little bit of the yellow resin, if there's breakdown you'll generally see grey streaks, my no 6 cylinder coil had a lot of rust marks on the rubber insulation which I cleaned off.

I'm just using a rather old mains powered scope, I keep meaning to get a more modern hand held one but it works fine and I only seem to use it these days to diagnose the odd car problem.

The scope doesn't provide power it just lets you look at the waveform, the crankshaft and cam sensors produce pulses of around 0.5v (I think) as the engine is cranked which you can see on the scope. If you have a high impedence analogue voltmeter you should also be able to detect the voltage pulses as the engine is cranked - it's really difficult with a digital meter!!

I didn't remove the intake manifold (I've given up trying to locate the cps connector) I decided that I'd measure all the voltages at the ECU plug, so I just unplugged it and connected the scope/multimeter between chasis and the pin I was testing. When I removed the spark plugs and cranked the engine I couldn't smell any petrol so knew that there wasn't any fuel getting to the cylinders - I then did the voltage checks on the ECU plug.

[azale]

What I'm trying to find out, is if you had to pass power to the sensor to test for a pulse. I assumed power was routed to the sensor from the DME (because the diagram only shows two wires). I'm thinking, how can it pulse if I am just testing for resistance? At that point I'm only sending like a milli-milli-amp right? Is that all the power the computer sends through the sensor?

Lowell, I did *not* have any spark when I tested correctly last night.

I have a volt-ohm meter on my Christmas list.
Also, my wife called today to tell me that my computer disks are in. TIS, finally.

[stevebuk]

The Crankshaft and Camshaft sensors don't require power, they're essentially a coil of wire that generates a small voltage as the teeth on the pulley pass them.

[Javier]

diagnose it, specially if not an intermittent fault (about 1300 ohms between coil terminals in M50, both terminals open to third shield wire)

With a tester with frequency reading, you may be able to get a signal cranking the engine with the CPS unplugged to DME, CPS is a magnet inside a coil, when the steel tooth approaches it, the magnetic flux grows stronger and induces a voltage at coil terminals. Generally, also a small AC voltage reading will appear in the coil terminals when cranking.

Javier

[azale]

So 500,000 ohms sounds bad right? Would that kill spark and fuel injection?

btw- I received my Technical Information System CDs tonight from my eBay purchase. What a complete waste of money. Three CDs labeled 1, 2, & 3 with a permanent marker. So of course, I was shocked when they didn't work well.

Remember, you don't always get what you pay for, but you almost never get what you don't pay for.

[Bill R.]

on the e34's or any of the older cars... Its mainly for the newer cars Just out of curiosity where did you get your tis that it consisted of 3 disc's ?





So 500,000 ohms sounds bad right? Would that kill spark and fuel injection?

btw- I received my Technical Information System CDs tonight from my eBay purchase. What a complete waste of money. Three CDs labeled 1, 2, & 3 with a permanent marker. So of course, I was shocked when they didn't work well.

Remember, you don't always get what you pay for, but you almost never get what you don't pay for.

[Kalevera]

Excellent pictures.

Those are indeed candied coils. It's hard to say if it's the DME, but my money is on a fried final stage driver or 5; it could be fine given that it's flashing 1444 at the dash -- but I don't think that motronic 3.3 will report on the condition of the coils (therefore the final drivers). Before doing anything else, I'd check the position sensors, just to rule them out. I haven't seen this happen, but I've heard about it multiple times, both from people I work with and from the IAI crowd. #5 is the most common location for the problem. Some say it takes at least 3 worn coils to do it; others say a bad ground will cause it. Pull the DME and visually inspect pin #88 -- once a resistor is fried, the short can get it hot enough to melt plastic. Pop the cover and have a look at each of the 6 resistors/inspect and smell for damage. Find a known good DME and a set of new coils and swap 'em in/test.

But before doing any of that, be sure to do a few resistance and output tests on those sensors, inspect all grounds for bad wiring.

The starter solenoid piggybacks the starter -- from what I remember of the textbook stuff, the two most common types are mechanically intertwined. The starter turns the ring gear, which lives between a friction plate or a torque convertor, depending on the kind of transmission in the car, in the trans bellhousing.

EDIT: oh yeah, and TIS is a necessity. The latest (last) version was one CD, though -- it's now all online. Without buying a bound manual or a set of microfiches, it's the easiest and cheapest way to get basic repair info and TORQUE specs ;)


best, whit

[Javier]

So 500,000 ohms sounds bad right? Would that kill spark and fuel injection?
Locate and unplug the Crankshaft position sensor connector (CPS) and test resistance straight from their pins, there will be 3 pins there, one for the grounded shield and two for the pick up coil. You should have about 1300 ohms between the two coil pins, and open circuit from the shield pin to the coil pin (any one of them), having very high resistance value means the coil is opened.

If OK and the reading at DME plug is still 500K, there should be some weirdness between the CPS plug and the DME plug.

See attached picture for CPS plug (X6203) location and connection pin out (note it's seen the female side of the connection).

Javier

[azale]

Apparently, I got the TIS from some software pirate on eBay. One disk was supposed to be te TIS for every BMW model from '88 to '98 or something like that and the other 2 CDs are the ETK for all the models. It's probably the 20th derivative copy from the original and is suffering from de-evolution. I emailed the seller for a refund or better disks.

Lowell: What is the final stage or the nebulous "#5"? Are those addresses on the DME, underneath the cover? I will check it out tonight if the CPS is working well. Now I'm wondering who told me the starter was up front.

I will get to the CPS connector tonight but that means I have to remove the manifold. Thanks for the pictures, especially of the connector but I think the location picture is inaccurate. The wire for my sensor disappears under the intake but the picture looks like it should be on the passenger side. That would be easier, but I don't think I'm that lucky.

I guess replacing the sensor means removing the engine fan and clutch?

I hope this solves the problem. I'll write tonight after I test the CPS and I'll order the part for a big victorious repair on Monday.

[Bill R.]

http://www.bimmer.info/%7Ebill/m50%20crankpositionsensor.jpg
Apparently, I got the TIS from some software pirate on eBay. One disk was supposed to be te TIS for every BMW model from '88 to '98 or something like that and the other 2 CDs are the ETK for all the models. It's probably the 20th derivative copy from the original and is suffering from de-evolution. I emailed the seller for a refund or better disks.

Lowell: What is the final stage or the nebulous "#5"? Are those addresses on the DME, underneath the cover? I will check it out tonight if the CPS is working well. Now I'm wondering who told me the starter was up front.

I will get to the CPS connector tonight but that means I have to remove the manifold. Thanks for the pictures, especially of the connector but I think the location picture is inaccurate. The wire for my sensor disappears under the intake but the picture looks like it should be on the passenger side. That would be easier, but I don't think I'm that lucky.

I guess replacing the sensor means removing the engine fan and clutch?

I hope this solves the problem. I'll write tonight after I test the CPS and I'll order the part for a big victorious repair on Monday.

[Javier]

intake manifold for 1993 and not 1994!

Are you sure yours is a 94? Just enter the Vin (last 7 characters) in the on-line ETK (http://www.realoem.com/bmw/select.do) and get production date. 1994 corresponds to 9/93 to 6/94 production for 525i.

Just curious.

Correction: Just found that M60 and M50 name the connector the same, so the posted picture is for M60 instead of M50. Guess you'll be having a good time working this sensor issue.

Javier

[azale]

Originally posted by Javier
Guess you'll be having a good time working this sensor issue.
Been there done that.

I just removed the plugs for all the coils, bolts keeping the manifold on the block, bracket bolts underneath the manifold (at great cost to my sanity), vacuum hoses, air tubes for the throttle body, and for the alternator, and then I lifted that cursed intake manifold. I followed the sensor wiring into the heart of the beast and wiggled one hand in there to pull the connector from its bracket. But I had to get two pairs of pliers to separate the plug.

Then I tested contacts 1 and 2 to find 700,000 ohms of resistance. When I turned the engine over it did nothing . . . not even a hint of movement.

I will order my new sensor tomorrow and it will probably arrive on Monday or Tuesday.

Do I need to buy new gaskets for the intake manifold? The old ones look to be in very good shape.

I will get the VIN number to check on the correct year.

Do I need to coils or can I wait a paycheck or two?

This weekend I will be on Mackinaw Island soaking up some horse manure odor. I'll let you know if the sensor fixes the problem.

[Kalevera]

Mackinaw! Been a few years since I holed up in the Grand Hotel. Like the bridge, though. Surely you've heard the story about the Yugo flying over the edge.

Since you have the intake off, replace the gaskets. I'm relatively certain that the connector could've been reached by just removing the intake. Install the sensor, confirm that the engine is operating again, then replace the coil packs.

#5 refers to the fifth cylinder. Direct fire ignition is a different case than the single coil found on earlier cars (or two coils on the V12s). It would most likely appear as a misfire on your car.

best, whit

[Bill H.]

or what?


Been there done that.

I just removed the plugs for all the coils, bolts keeping the manifold on the block, bracket bolts underneath the manifold (at great cost to my sanity), vacuum hoses, air tubes for the throttle body, and for the alternator, and then I lifted that cursed intake manifold. I followed the sensor wiring into the heart of the beast and wiggled one hand in there to pull the connector from its bracket. But I had to get two pairs of pliers to separate the plug.

Then I tested contacts 1 and 2 to find 700,000 ohms of resistance. When I turned the engine over it did nothing . . . not even a hint of movement.

I will order my new sensor tomorrow and it will probably arrive on Monday or Tuesday.

Do I need to buy new gaskets for the intake manifold? The old ones look to be in very good shape.

I will get the VIN number to check on the correct year.

Do I need to coils or can I wait a paycheck or two?

This weekend I will be on Mackinaw Island soaking up some horse manure odor. I'll let you know if the sensor fixes the problem.

[azale]

Bill H.: The car is not running yet. I had my friend order the part on Satuday (while I was touring Fort Colonial Michilimackinac) from Autohausaz.com and they couldn't ship it until Monday (2 day - can you believe that UPS ground gets from AZ to HI before it gets from AZ to MI). So today I should have received it today but my wife wasn't there to pick it up so I have to stop by the UPS distribution warehouse tonight between 7:45p and 8:45p. I don't finish with church youth group until 8:15p, it's about a 25 minute drive, and I was supposed to meet with my Pastor to talk about a new bus we are considering. I'll figure some way to get it tonight and then my dad and I will try to install it before Law & Order. I forgot to order intake gaskets so I called Monday and emailed autohaus to get them added to the order but they couldn't include them in time. They cost 3 times as much around here ($36 total) so I was going to wait to change them until my next order from autohaus (probably coils next month or so). The gaskets really are in great shape. They are perfectly formed and still a vibrant bright blue. I'll look over the previous owner's documentation to double check when he last changed them. Is that going to ruin my car?

Mackinaw was forgettable as always. I say, keep the horses but allow electric carts, so the smell isn't so bad. One section of road on the way to the condo was completely drenched in horse feces and urine for a quarter mile and that is no exaggeration. I also saw Somewhere in Time for the first time: too many logical gaps for my taste.

I am familiar with the yugo accident but I try not to mention it to my wife, who is terrified of bridges. I just love the metal grate inside lanes. There is something exciting about driving 100' above water and being able to look down at it. On the ferry ride back from the island I was telling my wife that ferry boats are unsafe which is why I always choose to stand on the top deck, and then we found out about the disaster on Lake George that night . . . very sad.

I probably could have just removed the fuel rail and the rail with the electronics but I didn't know how to remove the injectors. So I just lifted both rails, injectors, and all the electronics.

If you don't hear from me tonight, I was in a sour mood because I didn't get my part.

[SRR2]

Some of the camshaft sensors use Hall Effect devices. Those would be the ones that crap out so often that a lot of E39 owners carry spares in the trunk. I'm not kidding.

[azale]

It wouldn't start.

I tested the new sensor versus the old sensor and there was a HUGE difference in resistance. I installed it and put everything back together (the intake gaskets are actually red, but still vibrant, and they were replaced in february). I replaced all the hoses and wires but I couldn't get the bolts up through the V shaped bracket into the intake manifold. I think I actually lost both bolts in the process (I lost one and my dad lost the other). I visually checked all the fuses and relays. Then I cranked it.

The battery was empty so I jumped it and put the cables in the engine compartment for hardly any noticable charge, then I jumped it straight to the battery. I let it charge for a grand total of 30 minutes but I was trying to start it off and on. The last time I tried to start it the engine was turning over fast enough (to me). I will trickle charge it all day tomorrow and I'll let you know what happens tomorrow night. If it doesn't start I guess it's back to the drawing board. I'll check for spark and fuel again.

So how do I remove the injectors? Any other ideas?

[stevebuk]

Sorry to hear that hasn't fixed the problem.

When you crank the engine with the spark plugs removed you should get a strong smell of petrol, if not there's definately a fuel delivery problem.

The first thing I would do is remove the connector to the engine management unit and check with the multi-meter that you are getting a continuous 12 volt supply to pin 26 and when the ignition is on at pins 48 and 54. If that is good then with a scope (you may be able to use your multimeter) check for pulses to one of the ignition coils say pin 1 and also check for injection pulses at say pin 5. If that is good I would check for pulses at the other coils (pins 2 3 29 30 31) and injectors (pins 6 22 23 33 50). If all these are ok, the fuel pump is running and you're getting pulses from the CPS then in theory the car should start.

[azale]

When you crank the engine with the spark plugs removed you should get a strong smell of petrol, if not there's definately a fuel delivery problem.I definitely didn't get that smell before but I will pull all the plugs and do a quick smell test first thing.


The first thing I would do is remove the connector to the engine management unit and check with the multi-meter that you are getting a continuous 12 volt supply to pin 26 . . .Does this mean check in the harness socket number 26 or the pin itself?


. . . and when the ignition is on at pins 48 and 54 . . .Is this for the pins or the sockets in the harness?

I guess my question is, does power for the computer come from he harness or is there a wire underneath that I'm not seeing? Also, I assume my computer is the connected to the harness located closest to the windshield. What is the other big harness for (looks like it goes straight to the fuse box)? These may sound like elementary questions but at this point in I obviously can't take anything for granted.

Let me emphasize that the main relay I replaced was definitely not clicking properly and the sensor I just replaced was totally hosed. There is no doubt in my mind.

I'm still waiting on my second set of TIS CDs and did I mention that my car has developed a small trans leak while sitting in a garage for the last 3.5 weeks?

[stevebuk]

I also didn't get that smell when my relay had died!

The pins I refer to are the plug that connects to the engine management unit, yes it is the one closest to the windshield, all connections to the management unit are through the single large plug. Slacken the cross head screw in the plug and unplug it from the management unit. Twist it around and make all voltage readings between the plug (you need a small tipped test lead for some of them) and a good earth. The pins are logically numbered - http://www.carsoft.ru/avtorepair/bmw_e34/8500.0/index.html

Personally I don't find TIS / ETK to be terribly helpful most of the time - did you download the Bentley manual? - there were a couple of links here recently for a free download!!

Providing you're getting all the positive supplies and pulses from the cps, the outputs from the control unit (injector and coil) are pulsing and fuel is being pumped it should start, the rest of the sensors generally affect how it runs once it has started.

ETA - It does have oil in the sump? If not some models will inhibit engine firing!

Also you may as well leave the plugs out until cranking it gives you a petrol smell, cranking without the plugs in will make the battery last a lot longer!

[azale]

Do I need to power the DME somehow to check to see if the injector/ingnition pins are pulsing?

I'll double check everything tonight.

Just downloaded the manual. I'll buy it on eBay if the price is ever reasonable.

[stevebuk]

To check the pulsing of the injectors / spark plugs the easiest way is to put the plug back in to the engine control unit and connect the scope / meter to the (disconnected) coil plug and injector connection - sorry for the confusion!

However the petrol smell should tell you if the injectors are pulsing with the plugs and coil units removed.

I have in the past added an extra length of HT lead from one of the spark plugs to a removed but connected coil unit - I don't know if you've seen the Gunson colortune device, it's a sort of glass spark plug that lets you see the colour of the cylinder combustion (orange is too rich, white too weak and blue is correct) but the lead that came with that was good for extending the connection between a removed coil and plug. I could then connect a neon HT tester between the coil and the spark plug and watch it flash.

[Javier]

I tested the new sensor versus the old sensor and there was a HUGE difference in resistance.


Was the resistance about 1.3 Kohm? Was the sensor the exact replacement? though they look similar, they are not all the same. There is a groove in the sensor that should be aligned with the tooth wheel to pick up the position of the shaft.

I verified it once in an M42 we were trying to debug the CPS, and borrowed a similar one, fine resistance measure, but when installed was not working until we un-screw it and rotate it to match the grove position of the original sensor, and it made the difference.

Javier

[azale]

When I tested the sensors side by side the new one showed >1000 ohms while the old one showed >500,000 ohms.

I did not check the 'groove' but I will look at that before I sleep. When I put it on it didn't look like there were any options to rotate it.

I think the battery is too dead to turn the engine over now. I pulled all the plugs and turned it over for a while. I smelled gas but the smell was NOT overpowering. It was definitely there. The spark wasn't there for the most part but while I was holding the plug to a bolt, I saw a spark jump to the bolt but I couldn't replicate it. The the starter started clicking loudly because I think the battery could only power the solenoid.

I checked three pins. 26 good. 48 good when key in ignition. 54 BAD! nothing. what does this mean?

I hope I didn't fry my starter. I will put a better charger on it tonight.

[DanDombrowski]

Ok, I gotta clarify something here. >500,000 ohms resistance is not a resistance. Its an open circuit.

[azale]

I finally got a chance to look at the Bentley diagrams and now I have an important question for stevebuk.


. . . check with the multi-meter that you are getting a continuous 12 volt supply to pin 26 and when the ignition is on at pins 48 and 54.The Bentley Manual (130-27, DME 3.3.1 1993+ 525i) says pin 48 is output to the A/C compressor control. Why did you think/How did you know mine would have voltage there? 54 is input from terminal 87 on the Main relay and I will look into that tonight.

Javier- I didn't see a groove but I did see a marking on the old sensor. I didn't check to see if it was pulsing correctly when I replaced it. I had the intake manifold off and I didn't want to suck in any dirt. I guess I should have checked for pulsing from the DME harness post haste. If it isn't pulsing, through pins 16 & 43, I'll remove it and see if I can unscrew/rotate it at all. I hope that is the answer.

Now that I have the proper diagram (I hope) for all the DME pins, I'll check all the vitals tonight.

DanDombrowskiThe (anologue) ohm meter needle moved to about 600,000 ohms (from infinity) So it may be an open circuit but it's 'less open' than when the wires aren't touching anything.

Thanks for sticking with me guys. I know electrical problems are probably not a few of your favorite things but I need all the help you can give me. This helps me prove to my friends (and if this takes any longer, my wife), what I've been telling them since I bought it: that BMWs are worth it to own and repair. I can't thank you enough.

[Javier]

either it is the one for your car or it is not, only one position, but if the screw is removed, you can rotate and hold it in place wile someone else try starting the engine. As you know, the sensor looks like a metal can, in the top of the can there is a wire going out, in the side, there is a bracket with a hole to fix it to the engine, and in the bottom of the can, there is a line, that protrudes slightly from the can bottom surface (I'll try to post a picture tonight). This line, should have an specific alignment with the tooth on the wheel near the damper.

I do agree to check for pulsing before sticking your head under the engine to check it, if no signal there, and being the sensor new and within resistance parameters, I would say it is not the one for your car. You can verify by loosing the sensor from its place and comparing the relative position of the bracket and the groove, against the old one.


Javier

Javier- I didn't see a groove but I did see a marking on the old sensor. I didn't check to see if it was pulsing correctly when I replaced it. I had the intake manifold off and I didn't want to suck in any dirt. I guess I should have checked for pulsing from the DME harness post haste. If it isn't pulsing, through pins 16 & 43, I'll remove it and see if I can unscrew/rotate it at all. I hope that is the answer.

Now that I have the proper diagram (I hope) for all the DME pins, I'll check all the vitals tonight.[/QUOTE]

[stevebuk]

I used the pin numberings given here

http://www.carsoft.ru/avtorepair/bmw_e34/1210.10/index.html

when I was checking mine, I don't know if they're different to the Bentley manual?

(My problem was with my 520i not my 525i don't know if the pin numbering is slightly different?)

[azale]

The car started tonight!

The battery was fully charged. I tested the CPS and it *was* giving off pulses (thanks anyway Javier). Then I checked for spark and definitely got it. I put it all together and cranked the engine-Nothing. Then I jumped the fuel pump and it the beast purred like a kitten. Then I immediately put the fuel pump fuse back but the engine died. no power is getting to the fuel pump. I tried jumping the fuel pump before I replaced the CPS and it didn't run so we are headed in the right direction.

I can jump the pump at the relay too, so there must be a problem at the relay (which is brand new for those of you just joining the conversation). Looking at the wiring diagram, the relay coil is supposed to get voltage from the main relay, and pin 1 on the DME (either supplies voltage or opens up a ground [bentley 160-6]). I am definitely getting power from the main relay; the socket for fuel pump relay pin 85 (which should go to DME pin 1) acts as a ground (12 volts strong between the relay coil sockets). Last factoid: When the engine is off, I get about 50,000 ohms between fuel relay sockets 86 and 85 (not the relay, just the sockets it plugs into).

So experts I need your help:
What does pin 1 on the DME do for me: negative voltage or ground?
How do I test it? Then what do I do when it fails the test (it probably will)?
Did the CPS ruin something in the DME?
Is there a short between the relay sockets, bleeding out precious amperage for my fuel pump relay?
Should I just put a wire in there, instead of the fuel pump relay, and pray that I never get in an accident (oh yeah and don't leave the key in the on position when the engine isn't runnning)?

stevebuk-carsoft pin numbers are not correct for my car. There are all sorts of sockets missing, and unused sockets in use.

I might be able to use DME wiring diagrams specifically related to the fuel pump or DME pin 1, if anybody has those.

[stevebuk]

It's a wonderful feeling when you get the engine to run! That really is major progress.

I'm not going to quote any pin numbers as they're obviously different on your car!

This is from memory but I hope it helps - the engine management unit provides an earth (negative) connection to switch the fuel pump relay, you seem to be getting the positive supply to the relay coil which is good. If you're bridging the switched contacts on the relay to make the pump run then the wiring from the relay to the pump is good and the problem looks like the engine management unit isn't earthing the relay coil. I think there's an impact switch (can't remember where it's located) that stops the fuel pump after a crash but without looking at the wiring diagram I don't know whether it controls the engine management unit or the supply to the pump. Perhaps someone with access to the manual can chime in. You also need to check that there is a connection between the non positive side of the relay and the engine management unit connector.

The engine management unit should switch the fuel pump relay briefly when you turn on the ignition to prime the fuel supply, it then switches off the relay until the engine is running - does anyone know which signal is used for the management unit to determine the engine is running?

Sorry about the timing of my replies - time difference between the UK and US!

[azale]

According to my diagrams, the fuel pump uses the crankshaft sensor to determine if the engine is running. Unfortunately, 1. I know it's working and 2. the DME still doesn't run it to prime the fuel rail pressure before the first crank. I can't find anything about an impact switch but I have seen a crash control relay. I tested it to see if it was working a while ago and it was working fine, but according to the wiring diagrams I looked at, it just did stuff with the hazard lights.

There is no resistance between DME harness socket 1 and fuel pump relay socket 85. There are about 5000 ohms resistance between fuel pump relay socket 85 and ground when the harness is connected to the DME. There is about .5 milliamps going from fuel pump relay socket 86 to 85.

I'm trying to think of problems I may have caused when I repaired the sensor, or else problems the sensor may have caused. I hope my DME isn't ruined; did I mention it still hasn't given me a code?

Either way, I'm not too far from installing a small switch in my car to run the fuel pump when the key is in the ignition. I will also serve as a great anti-theft device. And it's tons cheaper than a new DME.

If you guys think of anything else let me know. I will install the switch next Tuesday or Wednesday if the devil is in the DME.

[Javier]

Let's follow some plan:

1.- I do not understand what do you mean "Then I immediately put the fuel pump fuse back", if you remove the fuel pump fuse, how did you get it running, the normal way to test the pump is to bypass (bridge) the power contact at the pump relay 30/87, but you need the fuse in place to run the pump. So please check fuse carefully, also measure with an ohm meter the fuel pump fuse F23. You can test the pump by connecting with a jumping wire, socket pins corresponding to FP relay pins 30 and 87. This will confirm proper operation of all FP circuit but the FP relay. Start the car with jumper in place, this will also confirm every thing is OK but the FP relay operation.


2.- Check your FP relay, you can apply Battery + to pin 86 and ground to pin 85 and feel it clicking. At the same time, connect the ohm meter to pins 30 and 87 and see the power contact closing (I mean, when you apply voltage to coil terminals 86/85, meter should read 0 ohms from terminals 30 to 87, and open circuit when coil is de energized.

3.- You already confirmed you get 12 Vdc at pin 86 of the FP relay, but have not confirmed DME is connecting to ground pin 85 (ground and - Battery are the same). You can confirm it feeling for the click in the FP relay at the specific moments it should energize, but first, discard a damaged relay per 2. If it turns out to be that DME is not activating the relay properly, have the DME fixed. May be it is only that relay pins 86 and 85 were accidentally connected, and output transistor actuating FP relay got fried (I doubt it as it must probably fail short circuiting causing the FP relay be permanently energized. Only huge amount of energy (a sustained short circuit in FP) would damage to open the transistor or the printed circuit board pads. In any case, you can take a look inside DME from pin 1, looking for evidences of such damage.

Do not risk your safety bypassing the FP relay

Javier

[azale]

I think I failed to communicate what I checked.

I was jumping the fuel pump from the fuse, not the relay. I was installing the fuse quickly in hopes that the relay had snapped after the car was running.

I checked and double checked the old relay (it was fine) and I replaced it anyway. I have also checked and double checked the new relay.

Regarding your third point:

There is no resistance between DME harness socket 1 and fuel pump relay socket 85. There are about 5000 ohms resistance between fuel pump relay socket 85 and ground when the harness is connected to the DME. There is about .5 milliamps going from fuel pump relay socket 86 to 85.
When the relay should be activating, the is 5000 ohms resistance at the DME. I assume that isn't a good ground. And I assume .5 milliamps isn't enough to trip the relay.

Can you think of any other sensor that would cause the DME to inhibit the fuel pump from priming the pressure in the rail after you turn the key? I assume if my CPS were the only problem, the pump would still run for few seconds when I turned the key to run right? Well, its definitely not doing that.

Do you know of a fast and cheap place that can repair my DME?
What about a $50 used DME on eBay? Too hard to match?

I don't think a manual switch for the fuel pump is as unsafe as sky-diving but I've never seen any statistics either.

[stevebuk]

I'd be wary of resisitance measurements when the DME is powered - I'd be inclined to measure the voltage between battery positive and pin 1 of the DME you should get 12 volts if the DME is switching.

A switch could be a short term measure but I would be concerned about the fuel pump running all the time, some DMEs switch off the fuel pump when the car is travelling down hill with the throttle closed and also after impact to stop the fuel pumping but not sure if the 5 series does this but I thought it did.

[Bellicose Right Winger]

The coasting w/closed throttle fuel cutoff is usually done via fuel injectors. I'm not aware of any mfrs that shut off fuel pump to do this.

The "impact switch" mechanism that shuts off fuel pump in an accident should be looked at. It sure seems odd though that there would be multiple problems, that is a bad CPS and something else.

Paul Shovestul




.......... some DMEs switch off the fuel pump when the car is travelling down hill with the throttle closed and also after impact to stop the fuel pumping but not sure if the 5 series does this but I thought it did.

[stevebuk]

Paul

Thanks for clearing up my confusion.

Steve

[azale]

I'd be wary of resisitance measurements when the DME is powered - I'd be inclined to measure the voltage between battery positive and pin 1 of the DME you should get 12 volts if the DME is switching.
I can test pin and battery positive tonight but I'll do you one better: I found 12 volts between fuel pump relay socket 86 and socket 85 (which directly connects to DME pin 1) while the DME was plugged in and powered. But I think the reason the relay still wasn't switching was the amperage.


The "impact switch" mechanism that shuts off fuel pump in an accident should be looked at. It sure seems odd though that there would be multiple problems, that is a bad CPS and something else.
I would like to hear more about the impact switch or crash control module but I don't think bahnstormer wanted to scan 500 more pages of wiring diagrams, and the diagrams I saw showed it working mainly for hazard lights/relays.

It does seem odd that there would be multiple problems but it's not impossible either. I could very easily have ruined something in all my electrical testing or sensor replacement. I am still baffled as to why the fuel pump wouldn't even run after I put the key in the 'run' position.

My friend Jerry Rigger says I could jumper a small ground wire to the fuel pump relay socket 85 wire to get the relay to switch when the key is in 'run.' Furthermore I could take out all the slack in the wire and attach a 5 oz weight to the center. If the car were in an accident of significant magnitude, the weight would pull the wire and disengage the fuel pump: mechanical fuel pump safety feature.

Whaddya think?

[Javier]

and car starts and run fine, + to FP relay 86 is OK and, and relay itself is OK, my only guess is that DME output transistor is damaged (or the contact at pin one of DME got bent or some how damaged in the connecting / un-connecting work you have been doing lately). The only sensor I know of being capable of shutting down the pump is the CPS, and it acts as a permissive for the pump, the engine is required to run in order to keep pump working, after the initial prime due to the key turn, when it would run briefly with the engine stopped. If it does not do that, sorry, DME output at pin 1 should be checked.

Javier

[Bellicose Right Winger]

Unless the crash control module is also a permissive for fuel pump operation, although it's connection to the DME isn't obvious. It's connected to the GM and the LKM.

Impact switch is under rear seat on left side.

If 12v was accidentally applied to pin 1 of DME, via fuel pump relay socket, and cranking followed, this would certainly fry the output transistor.

Paul Shovestul





and car starts and run fine, + to FP relay 86 is OK and, and relay itself is OK, my only guess is that DME output transistor is damaged (or the contact at pin one of DME got bent or some how damaged in the connecting / un-connecting work you have been doing lately). The only sensor I know of being capable of shutting down the pump is the CPS, and it acts as a permissive for the pump, the engine is required to run in order to keep pump working, after the initial prime due to the key turn, when it would run briefly with the engine stopped. If it does not do that, sorry, DME output at pin 1 should be checked.

Javier

[azale]

250V 5 amp fuses for my dad's multimeter: $6
DME/Main relay with shipping: $17
Crankshaft position sensor two day shipping from AZ: $105

Successfully starting my car after 4 weeks of troubleshooting and repair but having to get out of the car immediately afterward so when I wet my pants I wouldn't ruin my leather seats: Priceless.

I pulled the DME and looked in vain for burn marks or signs of damage. I replaced it and turned the key but the pumps still didn't run. Resigned that I would not be able to get a DME any time soon, I tested if my jerry rigging job would trip the relay and it would. I then ran a wire from fuel pump relay socket 85 to a ground. When I cranked the engine I flooded it. So I promptly removed my hack job and cranked until the engine worked out the extra gas. I assumed the engine would eventually die but it never did. So I tested for voltage at the fuel pump fuse: 12v, no complaints. I let it run for a little while, double-checked that my hack job was removed, and shut of the engine again. Then she started right back up and ran like a dream. I heard a disturbing noise for the first mile but then I pulled the hand brake and cleaned the drums. What a relief.

I assume when I pulled the DME it reset??? I'll let you know if it brakes down tomorrow.

You guys have been great. I bet you were hoping this thread would end about 30 posts ago but I think the ending makes it all worth it.

Please allow me to at least thank everyone who chimed in: ryan roopnarine, 632regal, DanDombrowski, Garlic Breath, genphreak, SSR2, Bellicose Right Winger and especially lowell, Bill R., Javier, and stevebuk

I know you guys are going to help me enjoy this car for a long time; you already have.

[stevebuk]

Great news!

Really glad you have it running and can enjoy driving it.

[Javier]

Javier