Fluctuating Idle/ Rough Idle on Warm Start?

woody888 · 10-17-2021, 09:35 AM

Hi guys. Any recommend strongly apreciated. When i start my car cold, it works perfect no problem at all.
All 8 cylinders start fastly. however, when the engine is hot, it feels like engine would'nt run on all 8 cylinders, sometimes even don't keep idle or even shut off (like the video attatched below).
I need to start the car with throttle pedal, let it run higher over 1500 RPM, than sometimes come easy to all 8 cyl.., sometimes not. Need to restart again.
I try in my opininon all possible. Main ground on the bottom, valve cover grounds, injectors new, spark plugs new, coils new, throttle actuators new, O2 sensors new.
Checked pipes for air leak, couldn't see by my eyes any problem.
Once running all 8, its working perfect with no issues, no problems.....
the only problem is that warm starting up. I'm really upset.
This issue really makes me crazy.

M3 hacker · 10-17-2021, 08:03 PM

Are any fault codes coming up?

My car seems to be doing the same (no fault codes showing) at the moment and I can’t sort it out either…

I’ve replaced the fuel breather valve and the ICV with no luck.

woody888 · 10-17-2021, 08:08 PM

Quote:

Originally Posted by M3 hacker

Are any fault codes coming up?

My car seems to be doing the same (no fault codes showing) at the moment and I can’t sort it out either…

I’ve replaced the fuel breather valve and the ICV with no luck.

Same as mine. I did not get any code. I replaced fuel breather valve. What is your symptom?
Exact same issue as the video i attached?

M3 hacker · 10-18-2021, 12:01 AM

Yep, pretty much the same as in your video.

Wally1552 · 10-18-2021, 06:53 AM

I've been through and currently still going through similar idling issue so feel your pain. I strongly recommend before throwing more parts at it, go to an indie/dealer and let them run ISTA on it or get ISTA yourself. It will allow you to see more info about any errors OR allow you to test individual parts such as the ICV, TA, sensors so you can start the process of elimination.

Sorry I can't be more direct help. Here is what I have learned thus far:
1) start with simplest/cheapest solutions which are usually things like FBV or trying different gas. Check all hoses, intake,, and plenum for any leaks. Check Engine ground cable is intact.
2) check all.sensors related to air and idling: intake sensors, vacuum sensors, O2 sensors, MAP sensors
3) lastly, check or pay a shop to test the expensive stuff like TA, ICV.

Goodluck

woody888 · 10-19-2021, 09:03 AM

Quote:

Originally Posted by M3 hacker

Yep, pretty much the same as in your video.

How's your m3 now? still same problem on warm strating?

Quote:

Originally Posted by Wally1552

I've been through and currently still going through similar idling issue so feel your pain. I strongly recommend before throwing more parts at it, go to an indie/dealer and let them run ISTA on it or get ISTA yourself. It will allow you to see more info about any errors OR allow you to test individual parts such as the ICV, TA, sensors so you can start the process of elimination.

Sorry I can't be more direct help. Here is what I have learned thus far:
1) start with simplest/cheapest solutions which are usually things like FBV or trying different gas. Check all hoses, intake,, and plenum for any leaks. Check Engine ground cable is intact.
2) check all.sensors related to air and idling: intake sensors, vacuum sensors, O2 sensors, MAP sensors
3) lastly, check or pay a shop to test the expensive stuff like TA, ICV.

Goodluck

For sure, I'll let the shop to check them. Have U solved your problem now?
what's your symptom on? same happen on warm starting?

Wally1552 · 10-19-2021, 04:48 PM

Quote:

Originally Posted by woody888

How's your m3 now? still same problem on warm strating?

For sure, I'll let the shop to check them. Have U solved your problem now?
what's your symptom on? same happen on warm starting?

Symptoms was idle dropping during warm idle. And fluctuating idle after reversing out of driveway after cold start. Then it simply went into limp mode one time.

I ran ISTA and both the bank 1 TA (30K miles) and my ICV failed all of the function tests within 1 week of each other. Just drove about 300 miles and so far so good. Idle is rock solid at 600 to 700 RPM. I will keep you guys updated.

M3 hacker · 10-20-2021, 06:27 AM

[QUOTE=woody888;28158264]How's your m3 now? still same problem on warm strating?

Sorry - I haven’t driven it again yet. It’s not my DD.

woody888 · 10-20-2021, 09:26 AM

Quote:

Originally Posted by Wally1552

Symptoms was idle dropping during warm idle. And fluctuating idle after reversing out of driveway after cold start. Then it simply went into limp mode one time.

I ran ISTA and both the bank 1 TA (30K miles) and my ICV failed all of the function tests within 1 week of each other. Just drove about 300 miles and so far so good. Idle is rock solid at 600 to 700 RPM. I will keep you guys updated.

Do you know what you specific have done? ICV?
and, your idle drops when it is warm "start"?

Wally1552 · 10-22-2021, 09:56 AM

Quote:

Originally Posted by woody888

Do you know what you specific have done? ICV?
and, your idle drops when it is warm "start"?

My situation may have been badluck in both TA and ICV going bad at Sametime. So replaced both. Just got back from 1K mile road trip. The car was rock solid.

woody888 · 10-24-2021, 08:16 AM

Quote:

Originally Posted by Wally1552

My situation may have been badluck in both TA and ICV going bad at Sametime. So replaced both. Just got back from 1K mile road trip. The car was rock solid.

My My apologies, Could you please tell that "TA" is??

sorry

Wally1552 · 10-24-2021, 04:00 PM

Quote:

Originally Posted by woody888

My My apologies, Could you please tell that "TA" is??

sorry

TA= Throttle actuators

woody888 · 10-28-2021, 10:39 PM

Quote:

Originally Posted by Wally1552

Quote:

Originally Posted by woody888

My My apologies, Could you please tell that "TA" is??

sorry

TA= Throttle actuators

OK, thanks man.
I'll replace brand new TA and will keep updating for the result.
The shop did tell me the Old TA may have issue. will keep updating

woody888 · 11-25-2021, 08:01 AM

Quote:

Originally Posted by Wally1552

Symptoms was idle dropping during warm idle. And fluctuating idle after reversing out of driveway after cold start. Then it simply went into limp mode one time.

I'm curious one thing, you mentioned idle was dropping during warm idle?
It means "warm"idle or "warm"starting(which means start engine when the car is warm)"
Is your issue was like the video I attached above?

I ran ISTA and both the bank 1 TA (30K miles) and my ICV failed all of the function tests within 1 week of each other. Just drove about 300 miles and so far so good. Idle is rock solid at 600 to 700 RPM. I will keep you guys updated.

How many miles when you found the TA and ICV were going bad?
I did replace the both brand new TA, it looks a bit better, buy still same issue if the car on warm starting.

[QUOTE=M3 hacker;28162101]

Quote:

Originally Posted by woody888

How's your m3 now? still same problem on warm strating?

Sorry - I haven’t driven it again yet. It’s not my DD.

I can't believe there are other owners have same issue. I think it's unusual.

woody888 · 11-25-2021, 08:03 AM

Quote:

Originally Posted by Wally1552

Symptoms was idle dropping during warm idle. And fluctuating idle after reversing out of driveway after cold start. Then it simply went into limp mode one time.

I ran ISTA and both the bank 1 TA (30K miles) and my ICV failed all of the function tests within 1 week of each other. Just drove about 300 miles and so far so good. Idle is rock solid at 600 to 700 RPM. I will keep you guys updated.

I'm curious one thing, you mentioned idle was dropping during warm idle?
It means bad "warm"idle or "warm"starting idle(which means start engine when the car is warm)"
Is your issue was like the video I attached above?

10-17-2021, 09:35 AM	#1
woody888 Private First Class 55 Rep 195 Posts Drives: E92 & F80 M3 Join Date: Nov 2014 Location: CA iTrader: (0)	Fluctuating Idle/ Rough Idle on Warm Start? Hi guys. Any recommend strongly apreciated. When i start my car cold, it works perfect no problem at all. All 8 cylinders start fastly. however, when the engine is hot, it feels like engine would'nt run on all 8 cylinders, sometimes even don't keep idle or even shut off (like the video attatched below). I need to start the car with throttle pedal, let it run higher over 1500 RPM, than sometimes come easy to all 8 cyl.., sometimes not. Need to restart again. I try in my opininon all possible. Main ground on the bottom, valve cover grounds, injectors new, spark plugs new, coils new, throttle actuators new, O2 sensors new. Checked pipes for air leak, couldn't see by my eyes any problem. Once running all 8, its working perfect with no issues, no problems..... the only problem is that warm starting up. I'm really upset. This issue really makes me crazy. Last edited by woody888; 10-17-2021 at 09:40 AM.. Reason: video added
	Appreciate 0 Tweet Quote

10-17-2021, 08:03 PM	#2
M3 hacker Private 71 Rep 98 Posts Drives: M3 e92 Join Date: May 2019 Location: Canberra Australia iTrader: (0)	Are any fault codes coming up? My car seems to be doing the same (no fault codes showing) at the moment and I can’t sort it out either… I’ve replaced the fuel breather valve and the ICV with no luck.
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10-18-2021, 12:01 AM	#4
M3 hacker Private 71 Rep 98 Posts Drives: M3 e92 Join Date: May 2019 Location: Canberra Australia iTrader: (0)	Yep, pretty much the same as in your video.
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10-18-2021, 06:53 AM	#5
Wally1552 First Lieutenant 122 Rep 334 Posts Drives: 135i Join Date: Jun 2009 Location: HI iTrader: (0)	I've been through and currently still going through similar idling issue so feel your pain. I strongly recommend before throwing more parts at it, go to an indie/dealer and let them run ISTA on it or get ISTA yourself. It will allow you to see more info about any errors OR allow you to test individual parts such as the ICV, TA, sensors so you can start the process of elimination. Sorry I can't be more direct help. Here is what I have learned thus far: 1) start with simplest/cheapest solutions which are usually things like FBV or trying different gas. Check all hoses, intake,, and plenum for any leaks. Check Engine ground cable is intact. 2) check all.sensors related to air and idling: intake sensors, vacuum sensors, O2 sensors, MAP sensors 3) lastly, check or pay a shop to test the expensive stuff like TA, ICV. Goodluck
	Appreciate 1 M3 hacker70.50 Quote

10-20-2021, 06:27 AM	#8
M3 hacker Private 71 Rep 98 Posts Drives: M3 e92 Join Date: May 2019 Location: Canberra Australia iTrader: (0)	[QUOTE=woody888;28158264]How's your m3 now? still same problem on warm strating? Sorry - I haven’t driven it again yet. It’s not my DD.
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