Fluctuating Idle on Warm Start?

[W Cole]

Hey guys,

Hoping someone here might be able to point me in the right direction. The car is still under BMW warranty but there is no check engine light so I think its going to be a battle to get the dealer to diagnose and fix the issue.

This problem (coincidently?) started after Crevier BMW replaced the spark plugs, oil, etc. during a routine service.

After a warm start only (usually after the car has been sitting for 45 minutes but could be as little as a couple minutes to maybe an hour and a half) the car will begin idling normally at around 600 RPM and then the idle will violently fluctuate 3-4 times between 400 - 1000 RPM. The car is a DCT and sometimes it will idle fine for several seconds in neutral but as soon as I put it into reverse the idle will begin surging.

Any ideas?

[BPMSport]

I've seen this happen on a bunch of cars. I would suggest a software update first, and if it's not that, it's probably an ICV on the way out (could take thousands of miles to throw a code or fail completely), or a throttle actuator issue in most cases.

[W Cole]

Thanks for the reply. I had the car updated by the dealer to latest firmware right around the time I first noticed the problem. Unfortunately, i can't remember if the problem existed beforehand. Is it possible upgrading firmware caused this issue?

[epbb]

Originally Posted by W Cole

Hey guys,

Hoping someone here might be able to point me in the right direction. The car is still under BMW warranty but there is no check engine light so I think its going to be a battle to get the dealer to diagnose and fix the issue.

This problem (coincidently?) started after Crevier BMW replaced the spark plugs, oil, etc. during a routine service.

After a warm start only (usually after the car has been sitting for 45 minutes but could be as little as a couple minutes to maybe an hour and a half) the car will begin idling normally at around 600 RPM and then the idle will violently fluctuate 3-4 times between 400 - 1000 RPM. The car is a DCT and sometimes it will idle fine for several seconds in neutral but as soon as I put it into reverse the idle will begin surging.

Any ideas?

Just had this EXACT same thing happen to me three weeks ago. Only difference, is my car is a 6MT. Idle would go back and forth between 500 and 1100. Took it to the dealer, and they replaced the Idle Actuator:

Idle regulating valve Permanent malfunction
1 13-62-7-838-085 ACTUATOR:136099
1341550 Replacing idle actuator (after vehicle diagnosis)
FC: 1341011500

Was completely covered under warranty. Take her in!

[W Cole]

Originally Posted by epbb

Just had this EXACT same thing happen to me three weeks ago. Only difference, is my car is a 6MT. Idle would go back and forth between 500 and 1100. Took it to the dealer, and they replaced the Idle Actuator:

Idle regulating valve Permanent malfunction
1 13-62-7-838-085 ACTUATOR:136099
1341550 Replacing idle actuator (after vehicle diagnosis)
FC: 1341011500

Was completely covered under warranty. Take her in!

Is idle actuator another term for the throttle actuator?

[kautiongsr]

Originally Posted by W Cole

Is idle actuator another term for the throttle actuator?

no idle actuator is just for idle.. i had mine go out.. 2011 with on 12k miles.. i would check faults first.. mine also does that idle fluctuation even after i replaced my idle valve..

[epbb]

Originally Posted by kautiongsr

no idle actuator is just for idle.. i had mine go out.. 2011 with on 12k miles.. i would check faults first.. mine also does that idle fluctuation even after i replaced my idle valve..

Just a note that this issue doesn't always throw faults (According to the repair tech who was M-certified, it takes several key cycles for it to throw an OBD error). When this happened to me, it didn't throw an error. Luckily, I was near the dealer when it started happening (~ 5 miles), and drove in to show them while the engine was doing it. They took it in, connected it to their system, and were able to get an error (Not a fault in the car) on their testing system.

Chances are, you'll have to take it in and tell them, have them connect it and run some tests. If they don't find something, then unfortunately, the only sure-fire way to get it fixed is to wait for it to happen again, and then take it to the dealer (Don't turn the car off, as it will reset the actuators).

[Grail05]

it could be as simples as bad gas...

try putting a techron 20 gallons and see if that goes away... but everyone had mentioned could be IA...

i had the same issue several months back and it was due to Fuel Pressure sensor... code is usually P0191 and P0195...

[kautiongsr]

Originally Posted by epbb

Just a note that this issue doesn't always throw faults (According to the repair tech who was M-certified, it takes several key cycles for it to throw an OBD error). When this happened to me, it didn't throw an error. Luckily, I was near the dealer when it started happening (~ 5 miles), and drove in to show them while the engine was doing it. They took it in, connected it to their system, and were able to get an error (Not a fault in the car) on their testing system.

Chances are, you'll have to take it in and tell them, have them connect it and run some tests. If they don't find something, then unfortunately, the only sure-fire way to get it fixed is to wait for it to happen again, and then take it to the dealer (Don't turn the car off, as it will reset the actuators).

i hear about that alot.. most scanner wont see all the codes.. but seriously if the ses light comes on it will store a code.. usually its in the shadow memory...

bad gas usually will always misfire on hard aacceleration..

[W Cole]

Are there any SIB related to the ICV / actuators? I took the car into the dealer today and mentioned SIB 13 05 08 but my SA could not find it in his system.

[W Cole]

Update: They replaced the ICV but it didn't fix the problem. Back to the dealer it goes..

[W Cole]

Dealer is stumped and says they can't replicate so are unwilling to go any further.

At this point I am pretty convinced the culprit is either a throttle actuator or as a result of the the new software update. The problem started shortly after they updated the software.

[epbb]

Originally Posted by W Cole

Dealer is stumped and says they can't replicate so are unwilling to go any further.

At this point I am pretty convinced the culprit is either the idle actuator or as a result of the the new software update. The problem started shortly after they updated the software.

I seriously doubt it's the software update. It's the actuator, and it's just not throwing codes like mine. Only reason I got it replaced without codes, was because I drove her into the dealership while it was actually happening.

Sent you a PM with more info. Keep us posted!

[W Cole]

So I ended up taking it back to the dealer this past week, the car is still exhibiting the idle problems on start up but I took it in because I noticed that when replacing the ICV they left off a piece of the intake and the engine was just sucking in hot air from the engine bay.

At this point I am 99.9% sure the idle issue is software and a result of them updating my car but they say I already have the latest firmware which may or may not be true and that simply "re-installing" won't do anything to fix the problem. They said they were able to confirm through "checksums" that the software is operating properly.

Any ideas?

[BPMSport]

Originally Posted by W Cole

So I ended up taking it back to the dealer this past week, the car is still exhibiting the idle problems on start up but I took it in because I noticed that when replacing the ICV they left off a piece of the intake and the engine was just sucking in hot air from the engine bay.

At this point I am 99.9% sure the idle issue is software and a result of them updating my car but they say I already have the latest firmware which may more may not be true and that simply "re-installing" won't do anything to fix the problem. They said they were able to confirm through "checksums" that the software is operating properly.

Any ideas?

Bring it to me and ill rule out any software issue for you.

[W Cole]

Originally Posted by Mike Benvo

Bring it to me and ill rule out any software issue for you.

Thanks mike. Ill get in touch with you Monday.

[GrussGott]

Originally Posted by W Cole

At this point I am 99.9% sure the idle issue is software

Any ideas?

Over the course of about 3 months that's what mine did ... then it trended into a rough idle, then more hesitation at low rpms - it would kind of pause, then it died during start up once, then a few days later I got all of the lights.

Turned out to be a failing bank 1 throttle actuator valve - they have to pull the manifold to get at it.

http://www.m3post.com/forums/showthread.php?t=769035

[Longwong]

Just had this problem as well. Random, no cel, no codes. Happened, dropped it off. Dealer replicated crazy idle and checked a number of things. Then said it was my xpipe with HFC lol. So I picked the car up and oddly the problem was gone and idles perfectly. So I am just waiting for it to happen again and hopefully throw a code!

[epbb]

Originally Posted by Longwong

Just had this problem as well. Random, no cel, no codes. Happened, dropped it off. Dealer replicated crazy idle and checked a number of things. Then said it was my xpipe with HFC lol. So I picked the car up and oddly the problem was gone and idles perfectly. So I am just waiting for it to happen again and hopefully throw a code!

That's ridiculous... Let us know if you get it resolved. Good luck!

[Longwong]

Yes especially since I had the x-pipe for 40k miles of trouble free driving lol. But I understand as they are mere sheep. They follow a protocol. With no codes or CEL they are useless.

Kind of like modern medicine where you get some doctors who rely overly on technology or flow-sheet's. If it does not exactly fit into one of their flow-chart's or objective test parameters they are stumped.

The dealer has been decent about me being x-pipe/HFC and have not made it an issue for many other random things so instead of push it I will just wait for a clear code. My car was stalling when I brought it in and they replicated the stall at idle so clearly they will need to see a code as it could not have been any more obvious.

That is life dealing with liking to do mods and going to the dealer! That is why I change my own oil, sparks, filters, sensors and anything else I can do to not haggle with them but some things are beyond my scope!

[RogEphedra]

Sorry to bump an old thread.

If anybody is researching this problem and has the following observations:

• fluctuating idle problem (down to 400 RPM, up to 1100 RPM, back down to 400 RPM, up to 1100 RPM, etc etc continuously)
• you notice or can re-create the problem after filling up with gas and then sitting idle for a few minutes
• also have the problem under other circumstances
• the problem isn’t related to cold starts

Then it is extremely likely your “fuel tank vent valve” aka “fuel tank breather valve” needs replacing. Replacing that fixed the fluctuating idle problem for me and others. See this thread called "E92 M3 Erratic Idle After Fill-Up":

http://www.m3post.com/forums/showthread.php?t=953477

[woody888]

I do have the exact same issue , any updated result with this? thanks