e30 325i cab starting problem!!! help!!

Fri May 01, 2015 3:02 pm

hi guys...... ive got a 1988 325i cab which has a starting issue!

i removed the inlet manifold and rocker cover for a lick of paint and put it all back together.

since then the car doesnt start up properly.

it fires up & then dies after 1 or 2 seconds.

the fuel pump is getting voltage on crank but not on ignition...i have also tried a another ecu from a 325 as afew people mentioned this online but still had no luck, does the same thing.

any ideas guys???

Fri May 01, 2015 3:12 pm

E30GAV wrote:
i removed the inlet manifold and rocker cover for a lick of paint and put it all back together.

With all new gaskets everywhere, and new O rings on the oil drain tube under the manifold?

it fires up & then dies after 1 or 2 seconds.

the fuel pump is getting voltage on crank but not on ignition...i have also tried a another ecu from a 325

Do you mean it does this every time, and you can't get ity to stay running? That's a symptom of a duff fuel pump.
One version of the ECU can have problems maintaining idle speed, but this can easily be overcome by pressing the throttle. Apart from that, it's very unlikely to be an ECU problem.

Fri May 01, 2015 3:23 pm

yea new gaskets everywer. the o ring was a crappy eurocarpart one was an awful fit. right pain to fit tbh.

yeah when firing it does this everytime. starts then dies. even by pressing the throttle no luck....does not react...simply just dies.

Fri May 01, 2015 3:31 pm

Very probably the fuel pump. It will run on full battery voltage, which it gets as soon as the crank shaft moves, but as soon as the compression in the engine builds up, the starter motor starts doing real work, it's current consumption increase, and the available battery voltage is dragged right down. At this point the pump quits.
Check by connecting a £10 ebay fuel pressure gauge up to the car and see what happens as you crank it.

Fri May 01, 2015 3:38 pm

would that o ring on oil drain tube cause the car to cut off like this? if theres a gap or something?

Fri May 01, 2015 3:39 pm

also is the pump ment to have power on ignition?

Fri May 01, 2015 3:48 pm

No power to pump on ignition. Don't think any car has had that since the '70s.
Severe air leak, such as that from a missing O ring, will cause it to idle badly, but would have much less effect under load and at higher revs.

Fri May 01, 2015 3:51 pm

thanks, i will try out another pump and see what happens.

Sun May 17, 2015 10:16 pm

hi guys just an update.....so as mentioned i tried a different ECU and also tried another fuel pump from my mates 325....stil no luck. the car fires up then dies immediatly after 1 or 2 seconds.

i unplugged the connector which connects to the AFM and tried starting it up.....this time the car fires up but starts reving up by itself ...quite high too. and i have to turn it off at this point as revs just keep climbing.

so clearly theres fuel going in for it to fire and rev like this right?

any ideas guys?? really bugging me now!

Mon May 18, 2015 10:48 pm

Mon May 18, 2015 10:56 pm

If it revs up by itself, then it must be getting air to be able to do so.
Check that the throttle is closing properly against its stop, and there are no air leaks after the throttle butterfly. If all is OK here, then it must be getting air via the idle control valve. Disconnect it and plug the pipe nearest to the engine. This should make the car idle very roughly at very low revs.