Fuel, spark, no fire. Cranks infinitely.

[maxthegearhead]

Hey guys. I'm pretty aggravated because I just pulled my 85 325e transmission to remove seized crank sensors, have replaced them, and put the trans back but am still having a no start condition! I used original Bosch sensors - both identical. What else could be going wrong? Fuel appears to be making it to the injectors and I have spark but the engine won't start. Any help you guys could offer would be greatly appreciated.

[superj]

did the tang come off the flywheel? I cannot remember if you mentioned it was still on there, or not, from the last thread when you said what was going on.

if you cannot remember, just undo the bolt holding the sensor in place and look in the hole while you rotate the engine over and look for the tang. if its not there, you will still have a no start issue

[maxthegearhead]

Now when i check I have no spark. The coil shows power though.

[superj]

but do you have the tang on the flywheel? are your sensors plugged in to the wrong connector? its easy to do since they look alike and are right next to each other. you can pull them out and look for the tang through the hole and then try swapping them if you have the tang on the flywheel. just have to rotate the flywheel all the way so you can visually make sure that metal tang is still on

[maxthegearhead]

but do you have the tang on the flywheel? are your sensors plugged in to the wrong connector? its easy to do since they look alike and are right next to each other. you can pull them out and look for the tang through the hole and then try swapping them if you have the tang on the flywheel. just have to rotate the flywheel all the way so you can visually make sure that metal tang is still on

I have verified the crank sensor is in the right plug and have also verified the pin is in place and in good condition. I have also purchased a known good used ECU to no avail.

[superj]

Anytime i had your issue, it was always either the flywheel or the sensors. I have never had a no fire issue from anything else.

I don't know. Your cam is turning?

I don't know what else makes a no fire besides the items you replaced already. Unless the wires or spark plugs are no good? You replaced the main things that usually cause trouble on an eta. I know, i have 4 in my driveway and have owned around 5 before these.

- - - Updated - - -

I am going to think about this for a while and get back.

[superj]

I found a similar problem and someone posted the pages of the bentley for checking stuff. I am not sure if you ha e a bentley so if you don't, try out the info from the pages

[maxthegearhead]

I have no spark at the coil so my distributor and plugs are irrelevant at this point. I'll keep updating as I keep trying things. My only theory at this point is faulty wiring.

[superj]

could be. check the bottom of the fuse box. I had a 528e that had some corrosion on the bottom of the fuse box that was causing all kinds of trouble

- - - Updated - - -

bottom of the fuse panel, not the actual box

[msservices]

I think a valid question here is...are we sure the crank sensors were the reason for the original no start condition? You mentioned them seized, as in stuck in their holes, but was removing them necessary in the first place? Also you mentioned having power at the coil, but are you checking for power and ground at the coil terminals, or just checking for 12volt using a different ground?

[maxthegearhead]

I have 12v at the coil when grounding to the engine block. The coil ground is only grounded when the motronic unit allows it to be am I correct?

[superj]

I believe so

[maxthegearhead]

I'm gonna try pulling a bunch of non critical fuses and checking every connector for corrosion. It's baffling, considering this is a clean rust free euro '85 325e with only 107k on it. It's literally a barn find car.

So as of this point here is the prognosis:

No injectors
No spark
Cranks strong
Dashboard lights all light up, interior electrics appear working fine
Compression is strong at ~160psi all cylinders
Timing belt appears in good condition
When in the run position coil gets 12v tested against chassis ground.
Main relay tested good.


This leads me to a few ideas:
1) unknown wiring fault of some kind between the DME and the engine
2) known good ecu is not actually good anymore (had a turner chip in it when I cracked it open)


thoughts?

[msservices]

Has there been any evidence of mice in the car? You mentioned barn find, and I have had them in mine just parked in my garage. Also can you verify the ignition switch and/or main relay is supplying power to the DME?

[maxthegearhead]

Has there been any evidence of mice in the car? You mentioned barn find, and I have had them in mine just parked in my garage. Also can you verify the ignition switch and/or main relay is supplying power to the DME?

Yes! there was some evidence of mice. There was a nest in the outer part of the air cleaner and one in the blower motor area. I cleared the nests and discovered frayed windshield wiper wires. No other wires appear to have been gnawed. The DME has power at all pins it should with the ignition turned to the run position. I have verified this against chassis ground.

[msservices]

Even though you mentioned having the sensors in the right holes, you also mentioned that they are identical, so have you tried swapping the plug connectors anyway?

[maxthegearhead]

Yes, I have. The manual says grey connector is to the crank position reference sensor, and black is for the crank speed sensor. The lower sensor is connected to the gray connector and the upper on eis connected to the black. I have swapped them and it seems to have made no difference either way. I'm going to consider one more ECU and if that doesn't work I'll cave and go through all the wiring manually by hand.

[msservices]

Too bad you can’t find someone close by that has an eta that could test your DME(s) so you could rule that out. Since you have two of them I would even consider shipping one to a someone if they were to volunteer to test one for you in their car. Having two not working at all seems unlikely, doesn’t that car have a separate idle control module? Could that cause a no start condition?

[maxthegearhead]

That's actually a fantastic idea.. I know a guy with a running eta and I could probably persuade him to test my DME's. Thanks! I don't think idle control module would cause a no start condition but i'll definitely read up on it.

[maxthegearhead]

Oh also - It is an 85 euro so very early production euro according to RealOEM - apparantly 2 ECU options could theoretically be found one ending in 007 and one ending in 027. Both the old and the replacement end in 027. It ran on two cylinders at one point on the old one but it may not be the original ECU? maybe replaced with the wrong one? maybe it needs 007 or are they identical?

[msservices]

Was it running on two cylinders when you decided to replace the sensors? Or was it completely dead? I am not sure what the original issue was when you pinpointed the sensors in the beginning?

[maxthegearhead]

Ok so I'll go through it chronologically.

I buy the car and tow it home
it runs on two cylinders - has no spark on any other cylinders
one day it just refuses to start and now has no spark at the coil
I test the crank position sensors and they test a bit out of spec so I replace them
no improvement
next i test the main relay and it tests good
eventually i end up replacing the DME and the coil still no improvement. No spark at the coil.

[msservices]

Have you thought about the possibility that the coil itself might be the problem ?

[M 7]

Have you thought about the possibility that the coil itself might be the problem ?

I totally agree, most of time its just bad grounding. that start the whole car go to junck yar.

check out my car, blown up gasket caused the oil on grounds , i had the sparks swimming in a pool of oil, but it was the grounds.

https://www.youtube.com/playlist?lis...OnIIxCHM5KwXc8

You can see the disaster after coils removal.

Dont laugh, i had to order new sleeves on Newly installed NGK

Sent from my SLA-L22 using Tapatalk

[maxthegearhead]

I replaced the coil already. No change. I'll see if I can find known good parts.