e34 not starting, has yellow spark need help.

[gmannino]

I'm experiencing a non starting situation. It cranks over but will not fire up. I'm getting slight hicups. I pulled out one spark plug and cranked my engine. I was getting a slight yellow spark but nothing like it obviously should. I also has a battery charger connected to the car so I know its not a battery problem. Since my spark is so low, I am assuming that my car will not start due to a ignition problem.

Do you guys think a bad Ignition coil could cause this? I tested the coil with a multimeter and my readings are off from the bentley manual. But I've heard much about the Crankshaft position sensor. I know where it is but I have not tested it yet. What are some ways to test the sensor? What is the resistance that should be across this sensor?

Any help would be greatly appreciated!!

One more thing is, I had a coolant hose burst on me and after that my car would not start. I am thinking maybe the coolant got onto the cps sensor or something like that. Would a bad coil prevent the car from firing? how about a bad cps?

[Rustam]

I'm experiencing a non starting situation. It cranks over but will not fire up. I'm getting slight hicups. I pulled out one spark plug and cranked my engine. I was getting a slight yellow spark but nothing like it obviously should. I also has a battery charger connected to the car so I know its not a battery problem. Since my spark is so low, I am assuming that my car will not start due to a ignition problem.

Do you guys think a bad Ignition coil could cause this? I tested the coil with a multimeter and my readings are off from the bentley manual. But I've heard much about the Crankshaft position sensor. I know where it is but I have not tested it yet. What are some ways to test the sensor? What is the resistance that should be across this sensor?

Any help would be greatly appreciated!!

One more thing is, I had a coolant hose burst on me and after that my car would not start. I am thinking maybe the coolant got onto the cps sensor or something like that. Would a bad coil prevent the car from firing? how about a bad cps?

Bad coil can prevent the car from firing if its bad enough not to provide needed potential. Yellow spark - bad.

Bad crankshaft position sensor can prevent the engine from starting. I think Bentley manual does provide information on how to check it.

I think it is an induction sensor, so you can attach multimeter leads to the ends to check for voltage spikes while moving a magnet next to it. You can probably find the needed contacts by consulting the wiring diagram at the end of the manual...

Good way to check sensor connection is by measuring resistance at the ECU connector - this way you combine the test of the sensor with the test of the wires leading to it.

[cschollum]

are all your spark plugs giving yellow sparks? you say yo only pulled one, have you tested other leads apart from that one and with other spark plugs, so as to rule out faulty leads or plugs?
faulty crank position sensor wouldnt result in yellow spark, youd either get no spark or in the wrong frequency
possibly faulty coil
but test plugs and leads first

[gmannino]

I only tested one spark plug. All the plugs are brand new. I just installed a new cylinder head and I got the car to run fine. Then I had the coolant hose burst and then the car didnt start.

I'm pretty sure the wires are ok. I will check the CPS sensor tomorrow and see what I find. Also is there another way to check spark from the coil? I was thinking of turning the car over while holding the coil's primary wire close to ground and see if i can get a spark.

[joshua43214]

What car are you driving? What engine? what year? Check all the plugs for spark, check the coil wire at the cap (do you have a cap?), check the wires at the plugs(do you have wires?) Worry more about spark strength than color, It should easily jump 2 times the correct gap with a snaping sound if strong enough. Use a thin screwdriver pushed up inside the boot(you have boots?) between the boot and the end of the wire(you have wires?), hold the boot with insulated pliers and see how far it jumps to ground. You said a hose burst? maybe coolant got into the plug wire bundle (wires?) and is causing cross firing, or it got under the cap(cap?). Hope some of this helps since im just guessing.

[gmannino]

Ya its a 1990 m20 bmw 525i.

[gmannino]

Ok guys, I spend the whole afternoon troubleshooting the car and I still could not get it working. Here are some of my test results.

-Ignition coil is getting power and works(i swapped with my other bmw and everything worked great)
-The fuel line going into the fuel rail has a high volume of fuel.
-The distributor cap and rotor are still new and in good condition. Wires are in good condition.
-Spark is still yellow. One thing I noticed with this is on my 87 528e I pulled out the spark plug and tested for spark and I shocked the **** out of me. The 525 doesnt seem to have as powerful as a spark as the 528e.
-Crankshaft position sensor is clean and pretty close to the pulley teeth. It also reads 530 ohms like it should. That is read from the connector so the wires and sensor seem to be good.
-The most troubling of problems came from my compression test. I test cylinders 1 thru 5 at 70 lbs, while the 6th cylinder was at 140 lbs. This clearly indicates that the rings are blown on 5 of the cylinders. But my question is this... If my rings are blown and my compression is low, would that prevent the engine from starting like it does?

My car turns over and sometimes hiccups but it will not fire up. I can also see, when i pull out the spark plugs that there is fuel on them.

What do you guys suggest as far as finding the solution to this problem? I'm seriously running out of idea's and feel like junking the car. But i really like this car and I prefer to get it running. Please help.

[Blitzkrieg Bob]

When the hose blew???

It may not be the spark

[gmannino]

That's right, the hose blew and i pulled on the side of the road. When I came to a stop my engine killed. I went to restart and it never started again.

Also when I disconnected my battery and then reconnected, I recieved a code on my dash of "code tacho" Anyone know what Code tacho means?

[gmannino]

I also tested for any codes and found out that my check engine lights blinks 17 times then blinks continuously. It just keeps blinking...

[joshua43214]

[QUOTE=gmannino]When I came to a stop my engine killed.[QUOTE]


Not sure I understand your meaning here. Do you mean the car overheated and died? if so, that is very bad and you may have cooked the head gasket. Take the coolant cap off and verifi the system is full, crank it over and see if it produces bubbles, a good sign the head gasket is blown. Overheating to the point of stalling is something very few engines can withstand and not blow a head gasket. Since the engine is very flooded from your description, I would attempt to clear the flood as listed below before doing a wet compression check.

Or do you mean you pulled over and killed the engine? Or you pulled over and the engine stalled but never overheated? The coolant from a burst hose may have saturated the plug wires causing a no start/stall until the wires dried out. The low compression could be caused by the rings being washed out by fuel. This can happen from repeated atempts to start the car with no or bad spark.

Also flooded plugs will not start the car, and some plugs will still not function well even after they dry. Remove all the plugs from the car, unplug all the fuel injectors and ground the coil wire, crank the engine to blow out the remaining fuel. use a propane torch to burn the fuel off the plugs, be careful not to over heat the plug and crack the insulator, the fuel will catch fire, burn it off and then stop there, or buy new ones(probably a better idea since you have cheap plugs). put the plugs back in, hook up the coil, leave off the injectors, hold the throttle wide open and start the car. If all goes well, the car should start after a few attempts, idle for a moment, speed up then die, start it again to ensure the flooding is completely gone, then rehook the injectors and start as normal. Get new plugs if you didnt already.

On extreme cases of washout, I have had to wet the cylinders with oil to raise the compression enough to start the car. Follow the above method for clearing extreme flooding, then squirt a small amount of oil into each cylinder, or dribble it down a length of bent coat hanger if you dont have an oil can pumper, crank the engine to swish it arround and blow out the excess, install the plugs and try to start. the danger with this is that you may oil foul the plugs to the point where they wont spark properly, so be prepared to sacrifice a set of plugs and try again.

Also, you said the wires are in good condition. How did you arrive at this assumption? Are they new? if so, what brand? I have seen cheap wires from autozone cause no starts within days of installation and their ignition caps be dead out of the box. resistance checking is a waste of time on 95% of the cases for a number of reasons, the most notable is that it does not test the insulation, which is the most common cause of wire related misfire. You need to verify spark at the plugs and not assume that since you have spark at the cap, and everything appears good, you have spark at the plugs. The majority of tow-in no starts from Do IT Yourselfers I have seen, had some obviose problem that was missed from making assumptions like this.

[Tiger]

You know... I am thinking that your crank position sensor is bad... half way bad that it did not send strong enough of a signal to tell coil to fire hard enough... Your mileage and age of the car is about right for crank position sensor going bad.

[gmannino]

[QUOTE=gmannino]When I came to a stop my engine killed.[QUOTE]


Not sure I understand your meaning here. Do you mean the car overheated and died? if so, that is very bad and you may have cooked the head gasket. Take the coolant cap off and verifi the system is full, crank it over and see if it produces bubbles, a good sign the head gasket is blown. Overheating to the point of stalling is something very few engines can withstand and not blow a head gasket. Since the engine is very flooded from your description, I would attempt to clear the flood as listed below before doing a wet compression check.

Or do you mean you pulled over and killed the engine? Or you pulled over and the engine stalled but never overheated? The coolant from a burst hose may have saturated the plug wires causing a no start/stall until the wires dried out. The low compression could be caused by the rings being washed out by fuel. This can happen from repeated atempts to start the car with no or bad spark.

Also flooded plugs will not start the car, and some plugs will still not function well even after they dry. Remove all the plugs from the car, unplug all the fuel injectors and ground the coil wire, crank the engine to blow out the remaining fuel. use a propane torch to burn the fuel off the plugs, be careful not to over heat the plug and crack the insulator, the fuel will catch fire, burn it off and then stop there, or buy new ones(probably a better idea since you have cheap plugs). put the plugs back in, hook up the coil, leave off the injectors, hold the throttle wide open and start the car. If all goes well, the car should start after a few attempts, idle for a moment, speed up then die, start it again to ensure the flooding is completely gone, then rehook the injectors and start as normal. Get new plugs if you didnt already.

On extreme cases of washout, I have had to wet the cylinders with oil to raise the compression enough to start the car. Follow the above method for clearing extreme flooding, then squirt a small amount of oil into each cylinder, or dribble it down a length of bent coat hanger if you dont have an oil can pumper, crank the engine to swish it arround and blow out the excess, install the plugs and try to start. the danger with this is that you may oil foul the plugs to the point where they wont spark properly, so be prepared to sacrifice a set of plugs and try again.

Also, you said the wires are in good condition. How did you arrive at this assumption? Are they new? if so, what brand? I have seen cheap wires from autozone cause no starts within days of installation and their ignition caps be dead out of the box. resistance checking is a waste of time on 95% of the cases for a number of reasons, the most notable is that it does not test the insulation, which is the most common cause of wire related misfire. You need to verify spark at the plugs and not assume that since you have spark at the cap, and everything appears good, you have spark at the plugs. The majority of tow-in no starts from Do IT Yourselfers I have seen, had some obviose problem that was missed from making assumptions like this.

Well the car came to a quick stop and then stalled out as I came to a complete stop. It only started to get hot after driving on the freeway and loosing coolant pressure and water. It never got into red. Again, the headgasket and cylinder head are completely brand new. The wire are still original but I only assume they work cause I have verified spark at the spark plug by pulling them out. I am getting a yellow spark, can't even hear it. I have read in the bentley manual that it should be blue with a loud snap. My spark is no where near that.

I tested my crankshaft position sensor with a multimeter and found it to be 530 ohms; the bentley manual says resistance should be around 540 ohms plus or minus 10 percent. So I assume that it is working correctly. Perhaps there is another way to verify its working well?

Also, I will do another compression test. I tried to start it many many times with fuel entering the cylinder. So I will do a dry compression test. I still have no clue on what is wrong with it.

Basically my spark is not a loud, snapping, blue spark and I need to know how to make it be.

[gmannino]

Ok guys I need some more help!!
I just added atf fluid to each of my cylinders and reinstalled my spark plugs. I attached my battery charger and cranked the engine. It seemed to want to start and spewed white smoke from the exhaust but it did not start. Now the car is doing the same thing. Just keep cranking over. I did some more testing.

-Fuel injectors have power with ignition and during crank.
-DME relay is working and fuel pump relay is working
-I can hear the fuel pump prime with ignition on and I can manually jump the fuel pump and hear it coming on. I can disconnect my fuel rail and fuel does come out.

Other than that, I am totally stumped on this problem. I am very close to giving up but I know I can fix it as long as I keep trying. Any help would be great.

[joshua43214]

Please answer the following questions;

did you crank the enigne after you put the oil in with no plugs installled? you must do this or you will oil foul the plugs, replace the plugs if yuo did not.

Did you disable the fuel pump when you attempted to start the car after oiling the cylinders? you must to this or you will just continue to floodthe engine, replace the plugs and repeat oiling making sure to crank engine with plugs out to blow out th eextra oil.

Where are you getting weak spark at? the coil wire or the plugs?

What brand of plugs wires and how old are they?

[gmannino]

Please answer the following questions;

did you crank the enigne after you put the oil in with no plugs installled? you must do this or you will oil foul the plugs, replace the plugs if yuo did not.

Did you disable the fuel pump when you attempted to start the car after oiling the cylinders? you must to this or you will just continue to floodthe engine, replace the plugs and repeat oiling making sure to crank engine with plugs out to blow out th eextra oil.

Where are you getting weak spark at? the coil wire or the plugs?

What brand of plugs wires and how old are they?

"did you crank the enigne after you put the oil in with no plugs installled? you must do this or you will oil foul the plugs, replace the plugs if yuo did not"
-No, I just oiled the cylinder and reinstalled the plugs then cranked it. So you say to oil the cylinder and crank with with the plugs out and fuel disabled? I can try that

"Did you disable the fuel pump when you attempted to start the car after oiling the cylinders?"
-I will try this, It just started to rain so I will do this asap.

"Where are you getting weak spark at? the coil wire or the plugs?"
- I am getting a small yellow spark at the spark plugs when I pulled them out. I crank the engine with one spark plug out and connected. I grounded the plug. Its a small yellow spark. The coil shoots spark if i hold it close to the distributor cap.

"What brand of plugs wires and how old are they?"
-The wires are factory BMW wires and they are original from what I know of. The spark plugs are brand new and only have been driven for 1 day.

[632 Regal]

WHAT BRAND ARE THEY?

The spark plugs are brand new and only have been driven for 1 day.

[joshua43214]

WHAT BRAND ARE THEY?

The spark plugs are brand new and only have been driven for 1 day.

I asked about the wires not the plugs, I have seen cheap aftermarket wires fail in a matter of hours. Also if too much oil was in the cylinders when the engine was started, they will be horribly fouled, they could be cleaned with a propane torch, but its not something I recomend to people I don't know.

[gmannino]

Well I just got it started! After doing the method that Joshua recommended, the car started up and ran. Although it was smoking from the exhuast tremendously. It would not stop. I ran the engine until it started to overheat on me. I am assume there is air in the line or unsuffiecient coolant. But when it started to overheat I shut off the engine. I got it to start up a few more time so I assume the starting problem is gone.

I need to know how to get it to stop smoking now... Its white smoke. SHould I just let it continue to run and try to get that smoke to burn away? I used ATF fluid, so white smoke it correct or not? What do you guys recommend?

[632 Regal]

definetly from the ATF, not a big deal, get the cooling issue sorted and bled ASAP. It might smoke for quite a while before it stops.

Congrats of getting it to fire up man!

[gmannino]

Thanks, hopefully this is the beginning of the end my the problems...

[gmannino]

nevermind that comment, i have problems again.

after letting it cool down, it will not start again. I checked the dipstick and I found a little bit of water in there. I'm not sure if it was water exactly but it did look milky. I has some leftover brown milky coolant/oil in my radiator but after replacing the head, i never seen it in the dipstick again, but today i found a small amount.

SO basically I cannot get it started yet. I'm thinking of taking it to a local european shop and just eating the cost.

Since there is white smoke and small amounts of milky substance in the oil, is it possible that head was not installed right or it cracked again?

[632 Regal]

Ewwww man....this could be the whole problem sorry to say. If the cylinder bolt holes had water or oil in them when assembled it probably hydrolocked the bolt holes and busted the block around every bolt, quite a common occurance. Hopefully the gasket got ****ed up but it could also be a cracked head...

Back to start here man...sorry bro.


nevermind that comment, i have problems again.

after letting it cool down, it will not start again. I checked the dipstick and I found a little bit of water in there. I'm not sure if it was water exactly but it did look milky. I has some leftover brown milky coolant/oil in my radiator but after replacing the head, i never seen it in the dipstick again, but today i found a small amount.

SO basically I cannot get it started yet. I'm thinking of taking it to a local european shop and just eating the cost.

Since there is white smoke and small amounts of milky substance in the oil, is it possible that head was not installed right or it cracked again?

[gmannino]

I blew those holes out with my air compressor, 150 psi. I think I will have the car sent to be leakdown tested. Is that a good recommendation?

[pingu]

> Do you guys think a bad Ignition coil could cause this? I tested the coil
> with a multimeter and my readings are off from the bentley manual.

What does the bently manual say for the ignition coil and what readings did you get for your ignition coil?

[632 Regal]

have to start somewhere, could be a faulty gasket or a cracked head.


I blew those holes out with my air compressor, 150 psi. I think I will have the car sent to be leakdown tested. Is that a good recommendation?

[gmannino]

I am sure that the coil is good, it was swapped from a working bmw and they both worked good. The headgasket and cylinder head itself are brand new. I would hate for those to be bad.

All I can try is to get the car started again and try to run it without overheating and try to burn all the oil out.
I got the car to start up by adding oil to the cylinder but now it wont start up again after that. Anyone know what it could be? I think imma have a leakdown test done.

[joshua43214]

Ya, I like your logic. Its a bit of a stress test on the ignition system to start the car when it is both flooded and the cylynders have oil in them, so I would have to say that the coil,wires, etc are good.. As you have seen, it takes very little oil to make a very big cloud of smoke. After getting the car up and running again, there should be no flooding issue, so any low compression will most likely be caused by a mechanical failure. I would attempt to get it running again before I condemned the head.

Good luck, hopefuly if it does have a mechanical failure, its just a blown head gasket and the other stuff is still good.

BTW, it will smoke for quite awhile until all the oil is burned from the exhaust. The oil will also need to be replaced after very heavy flooding.

[gmannino]

Thanks i'll let you guys know how it comes out. I hope i can find some time soon to work on it.

[gmannino]

One more question. I notice that the smoke was clearly WHITE smoke. I added pink ATF fluid to the cylinders. I was under the assumtion that oil burning in the cylinders was supposed to be bluish smoke. Since I added atf fluid, does that burn white or blue?

[632 Regal]

ATF will burn white, are you losing coolant?

[gmannino]

From what I have seen so far, no. But I have not had the car running enough to lose any coolant.

[gmannino]

Ok, I just did some more work on this car. I did a compression test on the car.

Cylinder 1 thru 6: 80, 80, 60, 80, 80, 100.

It still will not start, even with atf fluid added to the cylinders. It sounds like it wants to start and almost starts, but does not.

One more thing, with the spark plugs out, I crank the engine over and I can clearly see water shooting out of the spark plug holes on cylinder 2! So I am assuming that there is a leak. I talked to the man who I bought the cylinder head from and he said to take it off and bring it by for testing. So I will remove the cylinder head once again.

He also mentioned that one of the reasons for the low compression could be the exhaust valves and that one possible reason for the car not start is a clogged catalytic converter. What do you guys think about these conclusions?

[gmannino]

i also replaced the spark plug wires and those are ok. The machinest said that those low compression number will prevent the car from starting. Is this accurate to say?

[joshua43214]

haha, water shooting out of the spark plugs holes is a bad thing. sounds like something went wrong with the head install or he sold you a bad head.

Dunno where in left field the guy singled out exhaust valves as a likely culprit. The convertor would have to be totaly fused for it to cause a no start, so thats a bit of an odd statement too since you just had it running.

Give us a pick of the head gasket if you can when you get the head off.

Most likely the head just didnt get seated on properly, or was not torqued properly. what proceedure did you use to torque the head?

ya, 80psi accross the board will usualy be a no start.

[gmannino]

I will get some pics of the head and gasket. I used the recommended torque specifications in the bentley manual, including the 2 stage 90 degree angle torque.

[632 Regal]

sure it isnt ATF shooting out?

Thats real low PSI for compression, sure the timing belt/chain are dead nuts on? if its retarded 1 tooth you can get them kinda of readings in compression.

Just trying to save you the time of redoing it all if nothings wrong with the head.

Fuel wash can really de-compression an engine too.

[gmannino]

well the m20 is driven by a timing belt. I know the belt is ok and on right. I checked and rechecked the camshaft sprocket and the crankshaft sprocket during the installation and after the car broke down. Once I got it running the other day, it ran fine until it overheated.

The fluid was very water-like and was not oily, I just added water into the radiator.

[gmannino]

I pulled my head off and sent it to the guy who built it. he looked at it and he said that the head's exhaust valves look like they are burn and there are pits on the valve openings. He told me that the head was not holding a vacuum and that the exhuast valves needed to be re-seated.

He explained that from his experience, it looked like there was blockage from the exhuast intake and that it was back pressuring into the head. He said most likely it is a clogged catalytic convertor. So I am going to reinstall the head and try to break out the insides of the cat to get a nice smooth flow.

Does anyone have any experience or advice to what I'm about to do? I figured I would take out the oxygen sensor and run it like that or pound out the insides of the cat and hollow it out.

I still have not found out how water got into my cylinder walls.

Any help you guys?

[632 Regal]

I hope he isnt making you go round in circles here. Pits and burned exhaust is usually to tight of a clearance if adjustable. Clogged cat will not cause a no start condition unless its clogged 100% and seeing white smoke out the exhaust tells me its open enough to let the exhaust gas out. Oil the cylinder bores with a small amount of oil and a paper towel, oil goes a lot farther than ATF.

Again....

WHAT BRAND PLUGS and NUMBER ARE THEY?

[gmannino]

they are ngk plugs, factory spec for my car. THey worked great when i first got it running. He said that the car didnt start due to the low compression and that the head was not generating a vacuum.