Lumpy 325i

Post Fri Nov 10, 2017 4:15 pm

Hey zone just done a load of work on my 87 325i and I started it to make sure I had no air lock in the coolent and I noticed even when warm it's running lumpy and if you rev it when it settles back to idle it almost dies. Any ideas? Cheers.

Post Fri Nov 10, 2017 4:37 pm

Check for air leaks on the induction side.

Check that the TPS (Throttle position switch) is set up correctly.

Check that the ICV (Idle control valve) is clean and connected properly.

Read the wiki. http://www.e30zone.net/e30zonewiki/inde ... oubleshoot

Ben

Post Fri Nov 10, 2017 4:40 pm

Thanks man will check

Post Fri Nov 10, 2017 7:02 pm

If you disconnected the battery, the ECU will need to re-learn base idle settings - leave it to idle for at least 10 minutes, switch off, then go for a drive throughout the rev range.

Post Fri Nov 10, 2017 7:28 pm

Ahhh I see I'll give that a go the battery has been connected and disconnected multiple times. Also I read on the zone wiki but is the ICV supposed to buzz with ignition?

Post Fri Nov 10, 2017 9:02 pm

MiniC wrote:Hey zone just done a load of work on my 87 325i and I started it to make sure I had no air lock in the coolent and I noticed even when warm it's running lumpy and if you rev it when it settles back to idle it almost dies. Any ideas? Cheers.

My 320 does exactly the same thing,good luck, if you cure it let me know what it was please.

Post Fri Nov 10, 2017 9:12 pm

MAF. When it plays up hit the top hard and see if that cures it. Then you know you need another

Post Fri Nov 10, 2017 10:40 pm

MiniC wrote:Hey zone just done a load of work on my 87 325i and I started it to make sure I had no air lock in the coolent and I noticed even when warm it's running lumpy and if you rev it when it settles back to idle it almost dies. Any ideas? Cheers.

Running with a weak mixture for whatever reason. AFM (not MAF on an E30) is one of many possibilities. Air leak is another.

Post Fri Nov 10, 2017 10:42 pm

drakesmith wrote:MAF. When it plays up hit the top hard and see if that cures it. Then you know you need another

MAF?

Not on an M20.

Ben

Post Sat Nov 11, 2017 12:35 am

How can you look for an air leak on induction?

Post Sat Nov 11, 2017 9:39 am

With the engine idling, spray WD40 or similar around the inlet manifold gaskets; if the revs briefly rise, you have a leak.

Also, closely inspect all rubber boots, hoses, etc. going into the throttle body for cracks or splits.