E30 Zone

Hi
after having a rest over XMAS my trusty 320/327 has decided it wanted to muck about today and not restart after being left for 20 minutes .

remembering BM pasted tips on not starting , i checked for sparks all ok
then when on to fuel ( removed fuel supply pipe to find no fuel being pumped , so i shorted 30 to 87 on the relay and away we went fuel pumping nicely , this trick ot me home so thanks BM

i ve since looked at the wiring and found i ve lost the negative supply on the brn /green wirer from the ECU , ie the neg trigger to pick up the relay coil , ive checked this with a test ligth and used the DME relay switched negitve as a datum piont and my test light lights up with ignition on on the DME NEG , but not the FUEL PUMP SWITCHED NEG
as its too cold and dark know to continue , this leaves either an open cct or ECU fault
is the 172 ECU known to have this as a fault / weak link , in the that switched neg on pin 3 ? the relay in side the ECU fails often? is there any obvious thing to look for / repair in side it ? if not if i put a perminate negitive onto the brn / green wire it looks like the fuel pump rely would still operate as the ok as the DME =SUPPLY is feed from the red/white wire which is switched via the DME RELAY , any thoughts on this mod/ bodge BM or how to repair the ECU ? MANY THANKS

If the car starts and runs when you earth the brown/green that runs from the fuel pump relay to the ECU, then it does indeed look like an ECU fault.
As you say, the fuel pump will still be switched with the ignition switch, (via the ECU switching the DME relay), but you will lose the safety aspect of the fuel pump stopping when the engine stalls.
Not an ECU fault I've heard of or come across.

Thanks for the reply
i will try it tommorrow it may do as a temp fix (it runs on lpg most of the time and the lpg solenoid when open disable the fuel pump via a secondary relay , but thats working ok ,
i will look in side the ecu later
thanks for the info as normal

Brain
i have proved the loom and its ok and the fault is inside the 172 ECU somewhere , but have managed to put a chassis earth on it as discussed and at least it now starts ok
may be a new fault for your records
so i best look for a 2nd hand ecu next
thanks

exup wrote: so i best look for a 2nd hand ecu next
thanks

Got one here, Frank.

Cheers,
Chris