E30 325eS -- spark on all 6, injectors only firing on 1, 2, and 3... odd?

[2.5-12]

hey guys,

I have an 86' 325eS that I just swapped a spare motor into from an 85' 325e. C-101 was block to circle, so I just pinned it and spliced it to the car, it fires right up for the most part, but is only running on cylinders 1, 2 and 3.

I checked fuel pressure at 30 PSI which is pretty close to 2bar, should be sufficient. the car has spark on all 6, I listened through a long screw driver and heard injectors 1, 2 and 3 pulsing but 4, 5 and 6 were quiet.

anyone know if they run a common ground or something? I must have missed a wire when swapping the motors.

motor ran excellent in the car I pulled it from, so I'm assuming its not a problem of the harness or injectors... have tried two 027 ECUs as well just to make sure it wasnt a bad batch trigger.

thanks!

[JTapper]

Something is weird with that, because you should lose 1/3/5 or 2/4/6. I'm pretty sure thats how the banks are wired.

It's in the Bentley, and I have the ETM as well.

[2.5-12]

yeah, I knew the batches were 135 246 but I feel like maybe a common ground for the injectors got pinched off or something -- just seems strange that I lost the back three.

maybe I will try artificially grouding the 4,5,6 and see what happens.

[JTapper]

Here is a shot from my 1986 325 ETM, maybe this helps?

[JTapper]

And to add more confusion, from an unknown year M20 ETM:







I'd look here for your specific ETM's: http://www.wedophones.com/BMWManualsLead.htm

[Jigs]

A couple things you can try.

-Check and make sure you have 12v going to 4 5 and 6 injector.
- Check continuity from injectors 4 5 and 6 to pin 15 on the DME
- You can also ground pin 15 at the DME to see if you can get injectors 4 5 and 6 to fire. If they fire when you ground pin 15 and not when you crank the engine your DME is most likely bad.

[Jigs]

Ok I found what I was talking about. The banks on the 2.7Le engine are not 135 246, they are 123 456. Here is the wiring diagram:
http://www.wedophones.com/Manuals/BM...g%20Manual.pdf

Scroll down to page 125 and you will see the banks and how they ground to pins 14 and 15 via the DME

[2.5-12]

oh, wow ok.

so pin 15 is a ground to DME? I have tried two DMEs, I doubt its a bad DME, I will try grounding them after I test for +12V

Thanks guys -- those diagrams helped quite a bit and I had no idea the ETA batched 123 456 versus 135 246 on the Motoronic 1.1-1.3 cars

again, most helpful - thank you!

[Jigs]

Check to make surethere is continuity from 456 to pin 15. If there isn't you have some wiring issues. If you do have continuity to 15 then put a ground to it and see if they fire. If they fire you have a couple whack dme's

[Jigs]

and pin 15 is the ground from the dme that goes to the injectors. the dme uses it to fire the injectors, hence if ground to pin 15 causes them to fire it means your dme is not doing its job and is either fried or I guess it could be a faulty crank or speed sensor. I tried to find a wiring diagram for the motronic but I had no luck, that would be key

[2.5-12]

cut away some of the harness sheething, found a large brown/yellow wire with a failed connector to three small gauge brown white wires, connected them, started the car and I had 1, 2, 3, and 4 firing..

after that, I decided to check the connectors just to make sure they were.. connected.

pulled the 5 and 6 injector plug, the ground wire had been pulled out of the plug (probably with all the harness moving in the last 6 months of it being out of a car) so I pulled two plugs from my M60B40 harness, connected those, and the car fired right off at 6 cylinders.

its working great now.

thanks for the extra viewpoints on this guys, troubleshooting is always easier with a couple other people.