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E30 325i power loss

Posted: Sun Dec 14, 2008 2:15 pm
by ricointheuk
Hi :)

Any help would be appreciated. (1986 e30 325i)

While on the track at Oulton Park on Friday 12 Dec 2008 we had a problem with our car.

The first few laps and she was flying round, our head gasket and clutch change had worked well.

Then in third gear she would not rev past 5000rpm in 2nd she would rev all the way, so load makes a difference. If you just keep your foot to the floor it was if the engine just cut out. With each lap the rev range decreased 5000rpm to 4500rpm to 4000rpm etc. It also spread to 2nd gear. Below the cut out point she seemed fine.

If we revved the car in the paddock the she would rev all the way but would take a long time to return to idle.

If we then left the car for 15 mins it would then do another couple of laps with full revs before the problem started again.

Any ideas?

Thanks
Richard

Re: E30 325i power loss

Posted: Mon Dec 15, 2008 4:48 pm
by Ben5732
did it stutter mate or just loose power completely

Re: E30 325i power loss

Posted: Mon Dec 15, 2008 5:46 pm
by ricointheuk
Ben5732 wrote:did it stutter mate or just loose power completely
Hi Ben :) Just cut out with total power loss. It did have a little splutter here and there but more of a total loss. (inside the working rev range she was fine) A bit like when you hit the rev limiter. The engine was still turning from our momentum but was not firing, until we let our foot of the accelerator enough to bring the revs down to where the engine would still respond.

If we just kept our foot to the floor permanently it would stop firing and eventually the vehicle would come to a stop as the momentum was used up. We never went to a complete stand still because we just lifted of the accelerator to a point where the revs would return.

Thanks
Richard

Re: E30 325i power loss

Posted: Tue Dec 16, 2008 9:33 pm
by k11
That's interesting, sounds exactly like the problem I had at Aulton on Friday. Oh it's you ! Oh well let's see if we get any replies.

Re: E30 325i power loss

Posted: Tue Dec 16, 2008 11:19 pm
by E30Gheko
Sounds like your fuel pump relay could be on its way out. They tend to die over time rather than just work one minute and not the next, giving you all sorts of intermittent problems. Mine did the exact same and after literally cleaning the pins on the relay the problem went away although not completely. (after I'd replaced other parts that were probably not at fault!)

I have a new relay here but not had a chance to test if it's cured the problem altogether.

Re: E30 325i power loss

Posted: Tue Dec 16, 2008 11:27 pm
by stonesie
It could also be the pump itself slowing down so it can't keep up with demand, lift the back seats and undo the black cover on the drivers side so you can hear it running.

Re: E30 325i power loss

Posted: Wed Dec 17, 2008 8:57 am
by ricointheuk
stonesie wrote:It could also be the pump itself slowing down so it can't keep up with demand, lift the back seats and undo the black cover on the drivers side so you can hear it running.
Hi :)

We replaced the pump last year after it failed. So in theory it should be ok :/

Our pump is not under the back seat like most. Ours in outside behind the sill next to the passenger side back wheel.

r

Re: E30 325i power loss

Posted: Wed Dec 17, 2008 8:59 am
by ricointheuk
E30Gheko wrote:Sounds like your fuel pump relay could be on its way out. They tend to die over time rather than just work one minute and not the next, giving you all sorts of intermittent problems. Mine did the exact same and after literally cleaning the pins on the relay the problem went away although not completely. (after I'd replaced other parts that were probably not at fault!)

I have a new relay here but not had a chance to test if it's cured the problem altogether.
Hi :)

We will try this and see if it makes a difference.

r

Re: E30 325i power loss

Posted: Wed Dec 17, 2008 10:11 am
by JungleGus
I would try a different AFM first, then dizzy - coil/leads/spark plugs check (see bently for details)

then try testing the TDC and CA sensors

i hate these problems!