Author Topic: Fast Idle Issues (Read 2748 times)

Noctesolis · « **on:** May 20, 2009, 10:43:25 AM »

Im running a e36 318i with a m42b18 engine.

So out of the blue my car won't run below 1300-1500rpms at idle. When I start it it idles normal, 7-800 or so rpms then after a few minutes it gets up to 1300-1500 and fluctuates between them.

Every 5 seconds or so it acts like it stalls for a millisecond and goes from 1500-1300 then back up again.

Any ideas on what might be causing such erratic behavior? I'm going to clean the ICV extremely well today and all the vacuum lines seem good, other than that I'm not sure where to start.

DesktopDave · « **Reply #1 on:** May 20, 2009, 12:39:19 PM »

I'll bet you're right...sounds exactly like a bad ICV or a big leak that the engine is overcompensating for. Could also be a wet DME (early e36s are famous for that) or bad AFM, but a flaky ICV or vacuum leak is much more likely.

Noctesolis · « **Reply #2 on:** May 29, 2009, 02:24:52 AM »

So I cleaned the ICV quite a bit but there really wasn't any buildup in it and I also replaced every single vacuum hose under the hood.

Now the car no longer stutters from 1500-1300 every few seconds.

Now when I start it the rpm's are good while it is cold, they hang out around 7-800. Once she warms up it jumps up and stays at 1400 for good at idle, no stutters just a constant 1400. O2 sensor is new so I marked that off the list, I'm also going to put on a different FPR tomorrow that I have sitting around so I can mark that off the list also.

Anyone have any other suggestions on how I can get the idle down? It runs like a champ but the excessive idle annoys the hell out of me so I would like to get it fixed.

Noctesolis · « **Reply #3 on:** June 04, 2009, 01:11:32 AM »

Alright back to the crappy 1500-1300 randomness. I'm seriously ready to start kicking kittens. The idle stays strong at 1400 then randomly jumps to 1500 and bogs to 1300 every few seconds... it's like it stutters down to 1300 then jumps back up to 1500 when the car has been driven a lot and it's good and warm.

I doubt this is related but my temp gauge is going nuts on me too. It works 95% of the time then it randomly crashes to nothing for a few minutes then back up.

Any ideas?

On another note I scored a 96 318ti today for 800 bucks in mint condition minus the headliner from a random guy that lost his job... I'm about to drop this 318i to some poor sap on craigslist and let them figure out the idle at this point.