Fail start in my E34 535i M30 1989

[efxview]

Try all
Coil ok
spark plug ok
distributor cap & rotor ok
battery ok
crankshaft rpm sensor ok
coil is powered +12v and -12v but there is no spark
the sensor in spark wire cyl N°6 how many Ohms work?

some suggestion??

Best regards

[Adnan]

Hi,

Do you have a Bentley manual? Highly recommended.

However, I couldn't find the resistance specification for the #6 pickup but you should be able to check for continuity. If it's open, you have a problem. According to Bentley, you should see a pulse across pins 8 and 31 of the ECM.

I'm assuming that you have checked the secondary of the coil and it's not open?

Regards,
Adnan

[joshua43214]

Do you have injector pulse? you need to know this to narrow your search.
Did you check for spark at both the coil and the plugs? did you check more than 1 plug?
What do you mean by coil is powered by +12 and -12 volts? the coil is only powered by +12v and is grounded to 0v.
The sensor on the the plug wire is for the tach? car should start without its reference, someone correct me if im wrong on this please.

If you have no injector pulse, forget about the coil and wires and look for problems that involve both systems. Most common cause is bad crank angle sensor, but can be wiring or DME itself.

If you have no spark at the coil, remove the neg terminal and verify 12v at pos. If good check at neg, if no 12v at neg, replace coil. If 12v at neg, attach neg terminal and verify grounding of coil using a tachomer. If you have a tach refence replace coil, if not then you have no ignition control and you need to dig deeper, do you have any anti theft systems? You did check for injector pulse already, right?

If you have spark at coil but not at plugs, check the cap and rotor, after market parts here are usualy pure junk. Verify ignition wires are hooked up in proper order, It is very easy to muck this up, and I had a car towed in from another shop because there "tech" got the firing order wrong, he clained it was a misprint in his service manual when the customer asked him about it.

[Adnan]

Hi,

On the M30 with DME 1.3, the #6 sensor is required to tell the ECU which bank is which. Without it, the system can't operate. The M50 and M60 don't have it.

Regards,
Adnan

[joshua43214]

Hi,

On the M30 with DME 1.3, the #6 sensor is required to tell the ECU which bank is which. Without it, the system can't operate. The M50 and M60 don't have it.

Regards,
Adnan

Cool, thank you very much for the clarification. I am thinking that the computor would use a default setting based on the CAS while cranking so that it would have a reference to use, then use the wire sensor when the key is returned to run position. Please correct or clarify as needed.

[Bill R.]

DME 1.3 has a semi sequential injection system which triggers the injectors in clusters of 3, 1,3,5 and 2,4,6 every other revolution when the #6 sensor is working. When its not working it goes into parallel mode which shortens the injector pulse by half and pulses them all at the same time every revolution. Many people say that they can't tell the difference between semi and parallel. but the semi is supposed to be more precise and control emissions slightly better.



Hi,

On the M30 with DME 1.3, the #6 sensor is required to tell the ECU which bank is which. Without it, the system can't operate. The M50 and M60 don't have it.

Regards,
Adnan

[Bill R.]

dme 1.3 engines until the engine hits 600rpm then it switches over to semisequential unless no pulse is detected from the #6 sensor, in which case it continues to run in parallel mode.



Cool, thank you very much for the clarification. I am thinking that the computor would use a default setting based on the CAS while cranking so that it would have a reference to use, then use the wire sensor when the key is returned to run position. Please correct or clarify as needed.

[efxview]

If the sensor #6 is bad, does the engine start?
My sensor #6 it is not opened, but I will check the pins 8 and 31 of the ECM.
crankshaft rpm sensor looks good by multimeter continuity and resistance, but I will check on the ECM
I have a Bentley manual


Another question: my coil is a regular bosh (not original)it is necessary to put a resistance?

thanks every one

[Bill R.]

#6 plug wire, thats only for timing the semi sequential fuel injection. See my reply below.




If the sensor #6 is bad, does the engine start?
My sensor #6 it is not opened, but I will check the pins 8 and 31 of the ECM.
crankshaft rpm sensor looks good by multimeter continuity and resistance, but I will check on the ECM
I have a Bentley manual


Another question: my coil is a regular bosh (not original)it is necessary to put a resistance?

thanks every one

[joshua43214]

If the sensor #6 is bad, does the engine start?
My sensor #6 it is not opened, but I will check the pins 8 and 31 of the ECM.
crankshaft rpm sensor looks good by multimeter continuity and resistance, but I will check on the ECM
I have a Bentley manual


Another question: my coil is a regular bosh (not original)it is necessary to put a resistance?

thanks every one

Read the replies above, as others have stated, the car will start and run with the #6 sensor removed. Also, If you read my earlier post, you can see you resistance checking is not needed. Yes, it really is that simple to diagnose ignition no starts. I always loved tow-ins, 95% of no starts can be diagnosed in under 15 minutes and pay 1.5 hours in most of the shops I've worked in. Don't over complicate things and cause yourself extra work.

If you want to use an ohmeter on your coil, make sure you remove the small wires from it. You have to test resistance on 2 circuits, the primary and the secondary. The primary is the low power circuit accross the pos and neg terminals. The secondary is the high voltage circuit between the big coil wire and the spark plugs. Basicaly the primary circuit is a wire wound arround another set of of windings that make up the secondary circuit. As voltage passes through the primary circuit it builds up a magnetic field, when the primary circuit is grounded, the field colapses and passes through the inner windings of the secondary winding, causing a high voltage that is discharged through the plug wires. The secondary is connected to the primary via a resister(simplified I know). This is the basic operation of all 2 wire coils. Armed with this information, you can see that the coil should ave a very low resistance accross the primary posts and a high resistance between the primary and the secondary circuit. Coils differ as to what the primary to secondary resistance should be, a bentleys will have the Bosch stats.

So, now you have checked the coil resistance and it is ok, so the coil is good right? wrong. Bad insulation in the primary winding can cause a short circuit and cause weak spark even though it seems to pass resistance check. So basicaly, if you have power and a tach signal at the neg terminal with no spark, the coil is bad.

[efxview]

Change 2 coils and test this in other car and works fine all 2.
but in my 535i no spark.

how can I prove that the crankshaft rpm sensor works in ECM?

[joshua43214]

Something tells me you have not checked for injector pulse, the DME uses the CAS for reference for both injectors and ignition. almost all you need to diagnose this is posted on this thread or in your manual. Please read closely every thing posted and follow the advice.

You can always just toss parts at it until the car starts, that seems to work for many people as well.

[efxview]

I do not find relation between not spark and fail in the injectors, but as everything it happens for DME I will check it.

"the DME uses the CAS"???
I prove the sensor and it works well, now detect that the cable (-) of the coil goes directly to ground all time, it's ok? (I measured continuity from the pin 1 of the ecm disconnected, with (-)of coil, and ground).
see in diagram EWD-69, but the pin 1 in 3 part says NCA? (NCA is it a coneccion or a shield of insulation?)
for what I see the pin 1 it does not go directly to ground

[joshua43214]

(sigh)
ok, the relation between the injectors and the coil is that they both use the CAS(crank angle sensor) as a reference. If you have either one of them, the CAS is good, period. No further testing of the CAS is needed.

The coil is grounded by the DME, it can be grounded or not grounded depending on the position of the crank. You have been given a short concise series of steps, they must be followed in the proper order or they are meaningless.

Use a little logic here, If the DME is what is supposed to ground the coil, but it is grounded even when the DME is unpluged it means _____(fill in the blank)

I advise you tow it to a qualified service facility.

[Adnan]

DME 1.3 has a semi sequential injection system which triggers the injectors in clusters of 3, 1,3,5 and 2,4,6 every other revolution when the #6 sensor is working. When its not working it goes into parallel mode which shortens the injector pulse by half and pulses them all at the same time every revolution. Many people say that they can't tell the difference between semi and parallel. but the semi is supposed to be more precise and control emissions slightly better.

Hi,

I thought the system was true multi-port. Huh. I wonder why BMW chose not to do that since it's possible to achieve it with the pseudo-cam sensor.

Thanks for the clarification. Like I said, every day is a learning opportunity...

Regards,
Adnan

[efxview]

(sigh)
ok, the relation between the injectors and the coil is that they both use the CAS(crank angle sensor) as a reference. If you have either one of them, the CAS is good, period. No further testing of the CAS is needed.

The coil is grounded by the DME, it can be grounded or not grounded depending on the position of the crank. You have been given a short concise series of steps, they must be followed in the proper order or they are meaningless.

Use a little logic here, If the DME is what is supposed to ground the coil, but it is grounded even when the DME is unpluged it means _____(fill in the blank)

I advise you tow it to a qualified service facility.

When one asks it is for that he does not know, especially in a forum where the questions are problems, the logic indicates that the responses must be solutions.
if it was known the perfect functioning of a DME 1,3 he would not be writing

I am here to find solution not so that they send me to a qualified service.
according to you, where is the problem?
you say that it should continue the order, before create this, I did it.
were you thinking that it was the coil but not, were thinking that it could be CAS but not, that you think now?
and if you read the first thing that I indicate is that the coil is ok and the cas this ok
I am like to the beginning
I hope that they even should have patience and appreciate his helps

[632 Regal]

Joshua and Efxview, cool down, there is obviously aggrivation on both your sides...step back and try to realize bot of you are frustrated which fuels frustration.
sometimes it's simple, other times its so simple its complicated. Both of you know much more than i do on the subject, stick to it.
Efx, are you sire you read all the helpful posts?

[joshua43214]

Thanks Regal,

Ok, I'll try again, though after 5 posts on this topic to imply lack of patience is a bit odd.

Any experienced technician can tell from your first post that your knowledge of the engine is basic, in other words, you can use some tools, and a multimeter, but don't fully understand what the test results mean, and you can't yet see the entire gestalt of how an engine operates and what things must happen in order to make it run, and what needs to happen to make it run properly.

Knowing this, I can not assume that a simple statement that the coil is good is true, unless you say what you did to verify it. A simple resistance check does not mean a good coil.

Diagnosis is a proccess of breaking the problem into smaller parts until you arrive at the solution. Since some parts are used in both fuel and spark management, you need to know first whether both are affected. Hence testing for both no spark and no injector signal. If one works but the other does not, then the DME is recieving input.

"car cranks but will not start". This always starts with checking both injector and spark. If you have neither, then you proceed with diagnosing DME inputs. If one system is working, then you test the other system that is not.

All system tests must be peformed in the proper order since they depend on the previose step being correct.

Ok, since you have tried a known good coil, and you have verified 12v to the positive you can proceed as follows,

Install known good coil, check for tach reference while cranking at the negative terminal. This is important since this is the signal from the DME, if you don't have a tach, you can get a cheap one for your car for maybe $10-$15 at autozone, the basic analog type that can read low rpm is all that is needed. If you have a tach reference, and a known good coil, then substitute the coil wire and check again. But basicaly, if you have 12v in and proper ground reference from the DME, there really isnt much beyond a bad coil since you don't have a capactor on your model.

If you have no tach reference, unplug the DME and the coil and check continuity on that circuit, and from either end of it and the chassis. there should be very low resistance on the wire and infinite resistance to the chassis. If you have good wires to the DME, use the wiring diagram and verify that all the DME grounds are good and all 12v inputs are good. If they are all good then you may have a bad DME, but those are very reliable, so I would be worried about something else locking out the ignition like an anti theft circuit.

If you get to the point of condeming the DME, you have a choice between letting an experienced professional work on it, or do the hair pulling shot in the dark method of testing until oyu stumble on the problem. You could also try to find a used one cheap at the local salvage yard, make sure the numbers match.

I really can't help you further unless you do all the listed things in order.

Good luck

[efxview]

eurekkkaaaa, at least my car is running.... thanks everyone for every answer and for your time, I finally got the problem. the wire that goes from PIN1 of DME upto PIN1 diagnose connector was crushed just under coolant deposit, unluckly I bouth my car in this condition and it did not look in bad condition.

This cable is coaxial, and the shield was touching the cable.

Well, I understand that this is my first thread and for that you could have some question about my way to face and analyse your answers... but please, for future thread, belive me... for example: I allways said that coil was good, and many answers started saying check the coil.

With my ignorance in the system DME, I had certain doubts about that (-) of the coil was always to the ground, and Joshua clarified my that this was not possible and this was the key for the solution

[joshua43214]

Well done! That is an odd ball problem that many people would have been unable to solve and would have spent countless dollars on replacing parts. expecialy well done, since the problem lied inthe wire from the DME to the diagnostic connector and could very easily have been overlooked.