I did the search...still having no luck

[540Dave]

My 95 540i has baffled me with this idle/CEL issue. Some of you are having similar problems but one thing remains different for me..at least I think. Ambient temperature. In the warm weather of a few months ago I had no problems. Smooth idle. Lots of power. Never an issue. Did I mention the power? I used to own a 4cyl Camry.
Now that we have experienced some colder temps up here in Canada, my CEL has started coming on when the car is allowed to idle for more than a few seconds. A warmed up or cold engine seems to make little difference if it was below or near 5 degrees C (40F) when I first started out. The CEL will shut off if you get back on the gas quick enough, but leave the car to it's own devices for too long at idle with the CEL on and it will then stay on even in acceleration. If I allow that to happen the car will then idle rough, and may even stall out. Once the rough idle starts and the CEL is on I am stuck with this situation until I shut the car off for a while. Then I start from scratch with normal idle and no CEL. But it comes back. It seems worse with in town driving but that may be because it never gets a chance to idle on the highway but even then, if I am completely off the gas for a bit on the highway (long downhill or off the gas after hard acceleration) the light flashes on and then goes off when I hit the gas again. The kicker is that sometimes you get smooth idle and no problems. Sometimes after a run in town it will just stall dead as soon as you come to a stop. It varies. It runs great on the highway and has lots of power but only idles smooth with no CEL intermittently or for short periods. Is it the ICV? Is it a vacuum leak? Should I wait until spring and sell the car? I don't want to spend hours of labour on diagnostics at the stealer if you guys know what this is. Please tell me!

[Kalevera]

My 95 540i has baffled me with this idle/CEL issue. Some of you are having similar problems but one thing remains different for me..at least I think. Ambient temperature. In the warm weather of a few months ago I had no problems. Smooth idle. Lots of power. Never an issue. Did I mention the power? I used to own a 4cyl Camry.
Now that we have experienced some colder temps up here in Canada, my CEL has started coming on when the car is allowed to idle for more than a few seconds. A warmed up or cold engine seems to make little difference if it was below or near 5 degrees C (40F) when I first started out. The CEL will shut off if you get back on the gas quick enough, but leave the car to it's own devices for too long at idle with the CEL on and it will then stay on even in acceleration. If I allow that to happen the car will then idle rough, and may even stall out. Once the rough idle starts and the CEL is on I am stuck with this situation until I shut the car off for a while. Then I start from scratch with normal idle and no CEL. But it comes back. It seems worse with in town driving but that may be because it never gets a chance to idle on the highway but even then, if I am completely off the gas for a bit on the highway (long downhill or off the gas after hard acceleration) the light flashes on and then goes off when I hit the gas again. The kicker is that sometimes you get smooth idle and no problems. Sometimes after a run in town it will just stall dead as soon as you come to a stop. It varies. It runs great on the highway and has lots of power but only idles smooth with no CEL intermittently or for short periods. Is it the ICV? Is it a vacuum leak? Should I wait until spring and sell the car? I don't want to spend hours of labour on diagnostics at the stealer if you guys know what this is. Please tell me!


I don't understand what's different from this situation and the other current and old threads on this beaten-to-death topic?



best, whit

[540Dave]

I don't understand what's different from this situation and the other current and old threads on this beaten-to-death topic?



best, whit

Nobody else mentioned that it only happened when it gets cold.....did they?
If they did I apologize. I saw one that mentioned a supercharger that was close but still, with the intermittent and seasonal presentation of my cars symptoms I am not sure where to go. I would like to start with swapping out the ICV.

[Kalevera]

Nobody else mentioned that it only happened when it gets cold.....did they?
If they did I apologize. I saw one that mentioned a supercharger that was close but still, with the intermittent and seasonal presentation of my cars symptoms I am not sure where to go. I would like to start with swapping out the ICV.


;) Unlikely that it's the ICV.

This happens seasonally. Just look at all of the current threads on the same topic :D

Inspect and replace all compromised intake plumbing; pull the intake off of the engine to do it (and I've only actually done these with the engine OUT of the car, so I couldn't tell you how to do it with the intake IN the car):

- Rubber boot between MAF and throttle body
- Throttle body gasket
- PCV plate, rubber caps, O ring on the return line, gasket.
- Intake gaskets. Originals will be one piece (a good indication that they haven't been changed since it left the factory); newer are two piece.

Do all of that, reset the adaptations, and enjoy the car ;)

best, whit

[540Dave]

;) Unlikely that it's the ICV.

This happens seasonally. Just look at all of the current threads on the same topic :D

Inspect and replace all compromised intake plumbing; pull the intake off of the engine to do it (and I've only actually done these with the engine OUT of the car, so I couldn't tell you how to do it with the intake IN the car):

- Rubber boot between MAF and throttle body
- Throttle body gasket
- PCV plate, rubber caps, O ring on the return line, gasket.
- Intake gaskets. Originals will be one piece (a good indication that they haven't been changed since it left the factory); newer are two piece.

Do all of that, reset the adaptations, and enjoy the car ;)

best, whit


I don't mind putting some $$ out if I am doing what needs to be done. The ICV was just too easy as I can get one for $220cdn (bimmerspecialist.com) and could do it in about 20 minutes in my driveway. Off to my handy local garage I go. I'll let you know the result. Thanks for keeping me from spending money on the wrong part!

[632 Regal]

Hi Jim,

I know the answer cause I frequent the roadflea borad frequently, the problum widh your dards is caus the fiel pumb bolts have shag on them.

really I dont know **** so im wasting your time man...

http://www.bimmer.info/forum/showthread.php?t=15686

[ra_pro]

I had the same problems in Canada mostly in winter for 3 years on my 95 540i. Finally it got so bad over the summer that the car was almost undrivable. It's vacuum leaks. Had the the intake manifold seals and plate replaced, everything has been fine since then.

[540Dave]

I had the same problems in Canada mostly in winter for 3 years on my 95 540i. Finally it got so bad over the summer that the car was almost undrivable. It's vacuum leaks. Had the the intake manifold seals and plate replaced, everything has been fine since then.


Well...I got it back last night. You were all of course correct. Intake gaskets. When they got into the motor though they found that the centre plate in the middle of the V was also leaking coolant. THEN they saw as they were getting into that mess that all 4 knock sensors had been cracked, probably due to the moisture/heat etc that resulted form the coolant leak. THEN when they put it all back together the CEL came on again....MAF sensor was out. Thankfully they had a good used one in the shop. By the time I got it back I was up to almost $2K in repairs. I love my car I love my car I love my car...I'll keep saying that until I once again believe it.

[632 Regal]

well I'm glad it's finally back to normal, did you reboot the computer to clear the codes?

[540Dave]

They probably did at the shop......All these guys will work on are BMW's. When I rolled up there was a newer M5, two Alpina's and a very nice 740 on their way in for whatever they needed. The guy who owns the place hasn't put a wrench on anything but a BMW for 26yrs. At least they better have reset for almost $2K!!!! Thanks again for your advice.