Technical Car/Motor Issues > BMW 3-Series E30 - 89 2.5 poor running
Thread Author: apm Replies: 6

 BMW 3-Series E30 - 89 2.5 poor running - apm
Hi all,

Recurring problem with my E30. Comes and goes, but very bad at the moment. So here are the symptoms:

- rough running, like on less than 6 cylinders
- intermittent
- most noticeable when under load
- gets worse as the engine warms up
- I thought that it might be gunk from the fuel tank blocking the injectors- a big rev seemed to cure it
- I then thought that changing plugs got rid of it, but it has come back now
- seems to be worst at mid-throttle; low throttle it's less noticeable and at full throttle it more or less goes

Be good if anyone has insights before it goes off to the garage.

Many thanks in advance,

Alex.
 BMW 3-Series E30 - 89 2.5 poor running - corax
Sounds like a job for a good diagnostic place otherwise you could end up throwing money at it. I'm guessing but MAF sensor maybe needs cleaning or replacement. Or injectors. Or air leak. Or ignition related like porous leads. To name a few.
Last edited by: corax on Sat 1 Jun 13 at 17:21
 BMW 3-Series E30 - 89 2.5 poor running - R.P.
Or coil-packs - just had six new ones as a result of a recall...:-O
 BMW 3-Series E30 - 89 2.5 poor running - carmalade
Remove the dizzy cap and check for corrosion on the ht contacts,and also where the ht leads push into the cap.I have also seen poor running on these caused by hairline cracks on the rotor arm,especially on the underside.Need to remove it for inspection.hth
 BMW 3-Series E30 - 89 2.5 poor running - Number_Cruncher
I agree - check the HT system - best on an oscilloscope.

Another easy check is to look for cracks and splits in the rubber trunking to the throttle body and idle air control valve.

These engines need a strong vigourous spark to fire reliably, and will even begin to show increased HC levels at idle if the plugs have too small a gap.
 BMW 3-Series E30 - 89 2.5 poor running - apm
Thanks all.

I'll take a look at the HT system, and if nothing obvious is looking wrong, will book into my local indy or a look.

Alex.
 BMW 3-Series E30 - 89 2.5 poor running - Dog
>>I'll take a look at the HT system

"Or air leak" ~ vacuum.
Latest Forum Posts