RPM varies on start-up

DML3.0SI · 05-13-2023, 06:45 AM

Hi all, new owner sorting out a couple issues. 2008 3.0si Stratus gray. My RPM varies at start-up but settles down quickly. Any recommendations would help.
Also had a incident with a 10 point buck, both lost, now looking for a passenger fender and mirror.
Located in NE TENNESSEE
Any help would be greatly appreciated ��

Sterling Roadster · 05-13-2023, 02:53 PM

Hey awesome colour! Sorry about the buck but at least you have some frozen meat for a while. Anyway just my guess here but I had something similar to your start up/rev problem that was solved by going to an upgraded battery. I know it seems unrelated but I've had all sorts of BMW problems sorted by a better battery. On start up my car would go high on revs and then really low and occasionally stall, then once it warmed up it went away. I went to a battery with a little more cold cranking amps and it seems to be gone. I'd start looking into that and give the idle control valve a good clean. Good luck!

Clearancediver · 05-13-2023, 06:36 PM

M54 engines have the idle control valve… but the follow up engines I think don’t…

DML3.0SI · 05-14-2023, 02:32 PM

Thank you, I believe that was the case! Put a tender over night to bring to full charge, seems to have stopped issue. Time for battery upgrade. You’re suggestion is greatly appreciated!

Sterling Roadster · 05-14-2023, 03:00 PM

Quote:

Originally Posted by Clearancediver

M54 engines have the idle control valve… but the follow up engines I think don’t…

I think you're right, the N52 in my 328i doesn't have one either I believe. Back in my day they all had idle control valves I tell ya what!

Sterling Roadster · 05-14-2023, 03:02 PM

Quote:

Originally Posted by DML3.0SI

Thank you, I believe that was the case! Put a tender over night to bring to full charge, seems to have stopped issue. Time for battery upgrade. You’re suggestion is greatly appreciated!

Awesome! Happy to help. I lived with that for years and never could figure it out then one day I decided to upgrade the battery as a precaution and it was gone. I'll always take a simple fix when I can get one!

Our03z4 · 05-14-2023, 08:28 PM

Just fyi if you keep having issues after the battery you may need to replace the MAF connector plug. Easy to do and ECS Tuning sells the kit for like $25. Mine was having the rev issue and 3 codes pointing to the DISA and MAF. Changed the plug and perfection. It's starting to become a known issue that happens over time.

05-13-2023, 06:45 AM	#1
DML3.0SI New Member 3 Rep 10 Posts Drives: 08 Z4 3.0si Join Date: May 2023 Location: NE Tennessee iTrader: (0)	RPM varies on start-up Hi all, new owner sorting out a couple issues. 2008 3.0si Stratus gray. My RPM varies at start-up but settles down quickly. Any recommendations would help. Also had a incident with a 10 point buck, both lost, now looking for a passenger fender and mirror. Located in NE TENNESSEE Any help would be greatly appreciated �� Last edited by DML3.0SI; 05-13-2023 at 06:46 AM.. Reason: Added general location
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05-13-2023, 02:53 PM	#2
Sterling Roadster Second Lieutenant 68 Rep 279 Posts Drives: e85 Z4 3.0i & e92 328i Join Date: Aug 2015 Location: Toronto iTrader: (0)	Hey awesome colour! Sorry about the buck but at least you have some frozen meat for a while. Anyway just my guess here but I had something similar to your start up/rev problem that was solved by going to an upgraded battery. I know it seems unrelated but I've had all sorts of BMW problems sorted by a better battery. On start up my car would go high on revs and then really low and occasionally stall, then once it warmed up it went away. I went to a battery with a little more cold cranking amps and it seems to be gone. I'd start looking into that and give the idle control valve a good clean. Good luck!
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05-13-2023, 06:36 PM	#3
Clearancediver Lieutenant 90 Rep 406 Posts Drives: 2004 Z4 Join Date: Oct 2012 Location: Victoria, BC Canada iTrader: (0)	M54 engines have the idle control valve… but the follow up engines I think don’t… __________________ Sent from my smart phone...
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05-14-2023, 02:32 PM	#4
DML3.0SI New Member 3 Rep 10 Posts Drives: 08 Z4 3.0si Join Date: May 2023 Location: NE Tennessee iTrader: (0)	Thank you, I believe that was the case! Put a tender over night to bring to full charge, seems to have stopped issue. Time for battery upgrade. You’re suggestion is greatly appreciated!
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05-14-2023, 08:28 PM	#7
Our03z4 Captain 1692 Rep 685 Posts Drives: 2008 BMW Z4 3.0si Coupe, Join Date: Nov 2016 Location: USA iTrader: (0)	Just fyi if you keep having issues after the battery you may need to replace the MAF connector plug. Easy to do and ECS Tuning sells the kit for like $25. Mine was having the rev issue and 3 codes pointing to the DISA and MAF. Changed the plug and perfection. It's starting to become a known issue that happens over time.
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