OBD1 S52, no fuel, no spark

[TheRealE30kidd]

OBD1 S52 in '91 318is. Power at fuel pump connector (~12v, ~8v at the respective connectors.) No power at fuel pump relay (red/white striped wire) or fuel pump fuse (fuse 13.) E36 OBD1 harness with AKG adapter (if it matters.) No spark at coil, either.

Crank position sensor is supposed to read 1280 ohms (from what I read.) I'm getting 700 ohms. Not sure if that indicates a faulty sensor or what? It is a brand new CPS.

Really at a loss at this point of what to do. Help is much appreciated. Thanks.

[Jezza]

Is it a genuine bmw CPS or auto zone?

[TheRealE30kidd]

OEM. Bought all sensors from dealership.

[bimmer630]

main relay power?

[e30austin]

Main relay gets power except at the white/red striped wire. It clicks on when the key is turned to "on" position. ~12v at the thick red wire when cranking and when not. Swapped it with the one off my running 24v car to no avail.

And, actually, the CPS is supposed to OHM at ~540ohms. Ours was at 565ohms, so it was within spec. The source that I read "1280" from was incorrect. Just to clarify.

[328ijunkie]

Main relay wont fire unless the ECU tells it to. Nor will the FP relay.
Check power/ground connections by battery tray.

[e30austin]

Main relay wont fire unless the ECU tells it to. Nor will the FP relay.
Check power/ground connections by battery tray.

Was having dinner with a friend who said he was having the same issue in his E36 3.0 M50 (literally the same problem) and he said he changed the battery with a different one and didn't have that issue any longer...guess it's worth a shot.

Leaning towards a bad harness at this point. Not really sure what else it could be.

[mtlbloodshot]

Maybe this is weird, but on my M52 ODB1, I had no spark because if you look under the injector wiring tray, You will see a resistance. IIRC it is a 240 ohm, 2 watt. This resistance was fried on mine so I had to replace it. Turned the key and perfect.

[e30austin]

That would be an idea to try...but we're not getting spark, either, so I don't think that's the issue.

[e30austin]

Found this post on tech. Wonder if it applies to our situation. Don't remember what year the harness is from, but have a red label 413 DME. Not sure if that wire absolutely has to be snipped or it shuts off power to fuel pump relay, or what?

14. EWS – there is a lot of variability in which E36s have it and which ones do not. I used an ECU from a non-EWS vehicle but I still had some ignition issues after the conversion. There is an easy modification to the main engine harness to avoid any issues with EWS. You have to take the protective rubber boot off the connector to the ECU and cut wire #66. It should be solid green but it can also be black/violet according to the Bentley wiring diagrams. Just cut the wire and dress both ends with some electrical tape.

[mtlbloodshot]

Thats exactly what I wasn't having because of that resistance. Make sure you have ground before and after that dumb resistance.Once I changed it, my engine started 1 shot.

[e30austin]

Going to check the resistor and EWS wire tomorrow. If those don't check out, it's time for a new harness.

[328ijunkie]

EWS wire is not your problem.

[TheRealE30kidd]

Getting a little closer. Realized that the main relay wasn't clicking over. Tracing the wire from pin 56 on the DME connector as we speak. Hoping this fixes the issue. Goddamn harness adapters...

[EN318isPDX]

ignition switch?