Rough Idle - Cam timing?? 325es

[Chuck-Michigan-e30]

Hello everyone,

I am stumped (rough idle)
1986 325es
85,000 miles
Perfect compression
New plugs
Smoke tested for vacuum leaks
Plug wires checked for ohm resistance (all the same)
Fresh gas
It runs smooth and strong when driven
New timing belt
premium rebuilt injectors
32 lbs fuel pressure

I am at a loss.
I am wondering if the timing belt might be off one tooth????

Thanks for any ideas

Chuck

[82eye]

possible bad icv if no vac leaks.

[MrBurgundy]

did it happen suddenly or has it gotten progressively worse?

[Chuck-Michigan-e30]

did it happen suddenly or has it gotten progressively worse?

Recent purchase of the car so I do not have a history with it. It had 1000 miles put on it in the last 8 years.

[MrBurgundy]

Ahhh... that can be a tricky situation.

It could be cam timing, it could be bad gas, it could be this or that....

You gotta start with the basics and work to the timing, since that would be somewhat invasive to check.

Can you post a vid?

[82eye]

just to compare : pretty sure the timing is out on my new build - the result in the running condition is so dramatic you wouldn't be driving it.
i'm still going with icv. maybe try clean it.

[88Sedan]

As soon as I read 'rebuilt injectors' I though uh oh... those caused a major idling issue I was having that took me too long to figure out. Who rebuilt them? I learned the hard way they can be sold as rebuilt when what that really means is just new filters and o rings (no pressure or flow testing).

[packratbimmer]

Are the rebuilt injectors stock 325e injectors with the correct injector resistance unique to the eta cars? M20 cars will load up on fuel at idle if one does not get a tune matched to the injectors. Another thing to think about is whether the air flow meter spring has gone a bit limp - I would try to figure out if the idle is too rich in other words. Does the condition improve when you blip the throttle say every 10 seconds while idling otherwise?

[TobyB]

funny- I was going to ask what the idle AFR was- rich or lean- because there are so many different ways this can go...

t

[Chuck-Michigan-e30]

Are the rebuilt injectors stock 325e injectors with the correct injector resistance unique to the eta cars? M20 cars will load up on fuel at idle if one does not get a tune matched to the injectors. Another thing to think about is whether the air flow meter spring has gone a bit limp - I would try to figure out if the idle is too rich in other words. Does the condition improve when you blip the throttle say every 10 seconds while idling otherwise?

The idle was the same before replacing the injectors. The company that "rebuilt" them is: GB Remanufacturing

Chuck

[MrBurgundy]

IDK what people even mean when they sell "rebuilt" injectors.. can't rebuild 'em.... You can change the o rings, clean them, but that's about it.. maybe spray test them and that's considered a "flow match"

Check you FPR, pull the vacuum hose of the FPR when the car is running and see if fuel comes out..

If it's only at idle is gotta be an air leak or FP issue

[Chuck-Michigan-e30]

We checked the cam belt and it was spot on.
Chuck

[82eye]

does it stumble at all coming off throttle or coasting to a stop sign when rolling?

[e30davie]

Have you done a compression test? maybe its a leaky valve that only shows symptoms at idle.

My engine hadn't been driving for years before I got it, one of the valves would hardly seal upon testing, upon removing the head the valve seat was bad on one valve seat. I assume that valve was open during the non driving period and corroded.

[Chuck-Michigan-e30]

compression is perfect