OBD1 S52, no fuel, no spark

[TheRealE30kidd]

it was checked out when we did the test.

[TheRealE30kidd]

Ok, narrowed it down to a ground issue somewhere between the DME and the main relay. When we manually ground the main relay, fuel comes out. Checked all the ground wires and they are all good.

Every ground wire from the DME connector to the relays are good. No ground signal coming out of the DME though.

[Roland H]

Ground strap on the engine? What DME do you have? Cut that EWS wire anyway.

[e30austin]

Yup, ground strap is attached from pass side engine arm to frame. 413 red label dme. I was thinking of cutting it but don't think that's going to cause a ground issue (I could be wrong though.)

[328ijunkie]

The EWS wire doesnt go anywhere so no use in cutting it. The ECU controls the fuel pump. If its not firing the FP then look at crank signal or chip or ECU itself. The only thing the OBD1 electronics *need* to fire the motor are the ECU/Chip to be working and the crank sensor. You could have everything else broken and it would still fire. (sans coils/plugs and injectors obviously.)

[TheRealE30kidd]

We tried austin's ECU out of his car that is a good one and that didnt change anything.

[e30austin]

Crank sensor is also brand new and ohms out within spec (565 ohms.)

[TheRealE30kidd]

Ideas?! Still stuck. Only thoughts bad hardness??!

[328ijunkie]

Triple check your power/ground connections for the harness.

[mtlbloodshot]

You made sure the ground on the fuel injector rail is good? Make sure that resistance is not screwing you over.

[TheRealE30kidd]

Picked up an OBD1 harness from pick n pull along with another red label 413 just because. From a 1994 325is manual. It is still doing the EXACT same thing. No power to fuel pump relay or main relay.

I'm done at this point.

[328ijunkie]

Take a picture of your power/grnd connections at the firewall.
A pic of your C101 wiring would help too.

[e30austin]

Will do in the am (well, when I back to the car.)

[e30austin]

Here's the power block. Harness adapter is brand new from AKG, so I didn't get any pics of that.

[328ijunkie]

brand new doesnt necessarily mean correct. People make mistakes