Unstable Idle Revs

commedeschatons · 03-09-2019, 02:02 AM

I've had this issue for a while where after even a very small blip at idle the revs drop below the idle speed for a second and the car vibrates until they rise again and settle, even when up to temp.

sometimes the idle revs will fall and settle back like this even without any throttle input the entire time im stopped, but now in the winter it seems to be less noticeable.

some searching led to the fuel tank breather being implicated, but in those cases it seemed like people had much more flucation of the revs among other things so im not sure thats it

Am i crazy or is this normal for some reason? Anyone have this happening to them?

spazzyfry123 · 03-09-2019, 06:07 AM

Idle control valve ended up being what caused mine. I did a smoke test to verify.

Ram3n · 03-09-2019, 07:49 AM

I had that problem. Idle control valve was replaced. It went away. Only at idle is when it revs. I couldn’t stand it

commedeschatons · 03-10-2019, 02:16 PM

Thanks. I'll get that replaced asap

spazzyfry123 · 03-10-2019, 04:06 PM

I'd say look into having the throttle actuators replaced while you're in there. Free labor!

commedeschatons · 03-11-2019, 03:13 AM

Quote:

Originally Posted by spazzyfry123

I'd say look into having the throttle actuators replaced while you're in there. Free labor!

TAs have already been replaced so they /should/ be fine for a while, and i could care less about labor charges, this car has a warranty and i dont mind the shop siphoning off a couple more bucks for extra work in the future. keeps them happy.

Jonzny · 03-12-2019, 02:49 PM

Quote:

Originally Posted by spazzyfry123

Idle control valve ended up being what caused mine. I did a smoke test to verify.

Smoke test?

commedeschatons · 03-12-2019, 07:19 PM

Quote:

Originally Posted by Jonzny

Smoke test?

duh, i keep my cartons of cigs right next to my hex sockets

spazzyfry123 · 03-12-2019, 07:23 PM

Quote:

Originally Posted by Jonzny

Smoke test?

Yeah man

WA///M · 03-13-2019, 11:27 AM

Does the issue seem more pervasive after fuel fill ups? What’s you gas level like? My thoughts are fuel tank breather valve.

Good luck.

WA///M · 03-13-2019, 11:29 AM

Check out the conversation happening here:
https://www.m3post.com/forums/showthread.php?t=1592647

commedeschatons · 04-24-2019, 11:46 PM

update: after replacing both ICV and FBV this issue is still persistent.

Erickuokwa · 04-25-2019, 05:13 AM

Quote:

Originally Posted by commedeschatons

update: after replacing both ICV and FBV this issue is still persistent.

Does the car still vibrate when the revs drop?

Wally1552 · 04-25-2019, 05:59 AM

Quote:

Originally Posted by commedeschatons

update: after replacing both ICV and FBV this issue is still persistent.

Did they replace the icv hose when they replaced the icv?

commedeschatons · 04-25-2019, 10:31 PM

Quote:

Originally Posted by Erickuokwa

Does the car still vibrate when the revs drop?

yes

Quote:

Originally Posted by Wally1552

Did they replace the icv hose when they replaced the icv?

yes

Erickuokwa · 04-26-2019, 06:16 AM

Quote:

Originally Posted by commedeschatons

Quote:

Originally Posted by Erickuokwa

Does the car still vibrate when the revs drop?

yes

Quote:

Originally Posted by Wally1552

Did they replace the icv hose when they replaced the icv?

yes

Auto or manual? I think that sound may be a normal thing. Mine is manual and it drops like yours but not as much.

Drifter2090 · 04-26-2019, 10:06 AM

I had something similar and spark plugs just fixed it

Wally1552 · 04-26-2019, 10:36 AM

Quote:

Originally Posted by Drifter2090

I had something similar and spark plugs just fixed it

Maybe now is the time to take it to an indy to get scanned to pinpoint the issue before throwing more money at replacement parts.

My idle bounces as well and it throws an idle control code. took it to an indy and they used ISTA (i think? ) was able to test specific components. My idle control device came back faulty and but my TA were fine. So now I know what to replace.

commedeschatons · 04-26-2019, 11:48 AM

Quote:

Originally Posted by Wally1552

Maybe now is the time to take it to an indy to get scanned to pinpoint the issue before throwing more money at replacement parts.

My idle bounces as well and it throws an idle control code. took it to an indy and they used ISTA (i think? ) was able to test specific components. My idle control device came back faulty and but my TA were fine. So now I know what to replace.

Sadly there are no codes from this being thrown and we already did this process. Not sure what to do next.

flipmeraz · 04-26-2019, 01:17 PM

Quote:

Originally Posted by commedeschatons

Sadly there are no codes from this being thrown and we already did this process. Not sure what to do next.

Mine was doing the same thing a couple years back. Took it too the dealer under warranty and they did a software update on the DME and the problem went away.

Wally1552 · 04-27-2019, 05:58 AM

Quote:

Originally Posted by commedeschatons

Sadly there are no codes from this being thrown and we already did this process. Not sure what to do next.

Hmm if you took it to a reputable shop and they scanned it, misdiagnosed the issue aka you paid them to replace a part that was not the issue, maybe they will work with you to continue diagnosing at a fairly significant reduced rate? Good luck

nycplumber · 04-27-2019, 11:02 AM

How old are your engine mounts?

03-09-2019, 02:02 AM	#1
commedeschatons Second Lieutenant 134 Rep 216 Posts Drives: '11 335d, '03 Jetta Wagon Join Date: May 2018 Location: dfw iTrader: (4)	Unstable Idle Revs I've had this issue for a while where after even a very small blip at idle the revs drop below the idle speed for a second and the car vibrates until they rise again and settle, even when up to temp. sometimes the idle revs will fall and settle back like this even without any throttle input the entire time im stopped, but now in the winter it seems to be less noticeable. some searching led to the fuel tank breather being implicated, but in those cases it seemed like people had much more flucation of the revs among other things so im not sure thats it Am i crazy or is this normal for some reason? Anyone have this happening to them?
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03-09-2019, 06:07 AM	#2
spazzyfry123 Lieutenant Colonel 4359 Rep 1,913 Posts Drives: Here and There Join Date: Jul 2013 Location: North Georgia Mountains iTrader: (1) Garage List 97 Toyota Land Cruiser [7.50] 16 Toyota Land Cruiser [10.00] 11 BMW E90 M3 Stripper [10.00]	Idle control valve ended up being what caused mine. I did a smoke test to verify.
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03-09-2019, 07:49 AM	#3
Ram3n Private First Class 42 Rep 167 Posts Drives: 2008 e93 M3 Join Date: Mar 2016 Location: Gaithersburg Md iTrader: (0)	I had that problem. Idle control valve was replaced. It went away. Only at idle is when it revs. I couldn’t stand it
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03-10-2019, 02:16 PM	#4
commedeschatons Second Lieutenant 134 Rep 216 Posts Drives: '11 335d, '03 Jetta Wagon Join Date: May 2018 Location: dfw iTrader: (4)	Thanks. I'll get that replaced asap
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03-10-2019, 04:06 PM	#5
spazzyfry123 Lieutenant Colonel 4359 Rep 1,913 Posts Drives: Here and There Join Date: Jul 2013 Location: North Georgia Mountains iTrader: (1) Garage List 97 Toyota Land Cruiser [7.50] 16 Toyota Land Cruiser [10.00] 11 BMW E90 M3 Stripper [10.00]	I'd say look into having the throttle actuators replaced while you're in there. Free labor!
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03-13-2019, 11:27 AM	#10
WA///M New Member 3 Rep 6 Posts Drives: BMW M3 Join Date: Mar 2019 Location: Midwest iTrader: (0)	Does the issue seem more pervasive after fuel fill ups? What’s you gas level like? My thoughts are fuel tank breather valve. Good luck.
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03-13-2019, 11:29 AM	#11
WA///M New Member 3 Rep 6 Posts Drives: BMW M3 Join Date: Mar 2019 Location: Midwest iTrader: (0)	Check out the conversation happening here: https://www.m3post.com/forums/showthread.php?t=1592647
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04-24-2019, 11:46 PM	#12
commedeschatons Second Lieutenant 134 Rep 216 Posts Drives: '11 335d, '03 Jetta Wagon Join Date: May 2018 Location: dfw iTrader: (4)	update: after replacing both ICV and FBV this issue is still persistent.
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04-26-2019, 10:06 AM	#17
Drifter2090 Colonel 910 Rep 2,091 Posts Drives: E90 M3 \| E92 335i \| E90 335d Join Date: Jul 2015 Location: Ontario, Canada iTrader: (1)	I had something similar and spark plugs just fixed it __________________ MGM F82 M4 DCT / MPerformance / Swift / CSF / IND / Turner / BimmerWorld BSM F87 M2 6MT / Fabspeed / MPerformance / Turner / AutoID - SOLD JB-NB E92 M3 6MT / IND / RTD / Alpine / KW / ActiveAutowerke / 360Carbon - SOLD SS2-FR E90 M3 6MT / IND / AFE / ActiveAutowerke - SOLD AW-FR E90 M3 DCT / ACM / IND / AutoTecknic / K&N / H&R / Bilstein - SOLD
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04-27-2019, 11:02 AM	#22
nycplumber Major 686 Rep 1,230 Posts Drives: slow Join Date: Apr 2016 Location: nyc iTrader: (0)	How old are your engine mounts?
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