Low bouncing idle when warm

[BlackBMWs]

Troubleshooting question: looked through various posts, nothing conclusive come to mind...

My wife's 1997 TI, M44 has an intermittent idle drop once it is warmed up. Runs great until it's warmed up then will have a low idle (I.e. At a stop light) low enough where 1 out of 10 times it will die. Restarts just fine.

I'm thinking a slight vacuum leak once it warms up.

Any other thoughts or experiences out there?

Prolly 20k on the engine since I last installed it. At time, I swapped in new hoses for all rubber and new cooling pipes. The engine itself has 160k or so miles on it.

Runs strong above idle.

Thanks for reading and in advance for your thoughts. Cheers!


Sent from my iPhone using Tapatalk

[zoner]

Hey Rich! Long time no chat...

Does it happen immediately when the DME goes into open loop, or does it not start until the car has been warm for awhile?

I'm assuming you've ruled out the ICV...?

[BlackBMWs]

Hi Jerry! I trust all is well with you!

I suspect when it goes into Open loop. Since I was working with it much of the weekend, it really hasn't gone cold.

Swapped ICVs and not much difference. I did run the car at high revs for about an hour on the freeway with some Redline fuel system cleaner in half a tank of premium. My wife mentioned to me today she has been running regular for the last year. No idea of any carbon buildup or any other gunk. So, I'll let her run around for a week while I take a set of spare injectors, clean at test them. I also have a set of Magnacor ignition wires coming this week.

I do have another ICV I can swap in and test.


Sent from my iPhone using Tapatalk

[macilona]

Howdy...i have had a similar problem, and had it checked for a vacuum leak. The technician also cleaned and reconnected the throttle position switch, which has resulted in a marked improvement. I am not a mechanic, so i do not know how all this works, but thought i would pass it along. Happy trails, mac

[BlackBMWs]

Thanks Mac


Sent from my iPhone using Tapatalk

[macilona]

Just to clarify....it is the throttle position sensor! Good luck, mac

[BlackBMWs]

Yup, I'll be at it again this weekend


Sent from my iPhone using Tapatalk