Any L-Jetronics expert?

[aeronotix]

Hi,

I have just finished installing the M90 in the CS.
The M90 comes from a running euro '79 635csi. I have installed the complete engine harness with the engine.
Engine was running fine before pulling it and has fairly low miles (80kmiles).

The EFI is a L-jetronics with no cat no O2 sensor.

After installation I tried to crank it, but it is mad to the world:
https://youtu.be/veywR-I3oQI
It is running rough on all RPMs and running very rich. Plugs gets fouled in 10s running.

So far, I looked at the following:
- Fuel pressure. OK
- New fuel pressure regulator
- Valve lash set at 0.012"
- Swapped the AFM with another unit - same issue
- Swapped the ECM with another unit - same issue
- compression check: #1 & #6 the lowest at 155, others a bit above so it should be good.
- firing order checked. finger of the dizzy pointing at #1 cylinder at DTC.
- Timing chain seemed fine when I adjusted the valves and cam lobes cylinder #1 were both pointing down with DTC in balancer.
- I installed the headers and front muffler thinking it needs exhaust back pressure to properly run but still no difference.
Any idea were I could start to find the issue?

Thanks,
Stephane.

 

[richn123]

Check cold start injector

Check to see if cold start injector is stuck and if all the temp sensors are working

 

[sfdon]

Sounds like the water temp sensor/wires is a possibility.
Pin out the wires to the ecu from sensor.

 

[twistinglane]

I have Jim Blanton/Jim Rowe's well regarded and out-of-print L-jet trouble shooting manual and would be able to share an individual copy. For American cars though so not M90.

 

[sfdon]

Pin the afm temp and the water temp wires back to the ecu- those are known as ntc1 and ntc2
Negative Temperature Coefficient sensors read higher resistances when cold.
An open in the harness will trick the ecu into thinking it is -30 degrees.

Did you change out injectors?

 

[aeronotix]

Better...!

http://www.youtube.com/watch?v=Uth0vbA4cHE
Some of your comments pointed to the right direction.
I checked the cold start injection system. Wasn't causing any problem.
On the other side I cleaned the temp sensor, connectors to the ECM and temp sensor, cleaned all the grounds. It is running much better.
Idle is too high so I guess I'll need to check the air valve.
Hope keeping track of my this can help someone else going thru the same troubles.
Thanks for your help!