engine revving on its own

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Stevie64
Joined: Tue 24 Feb, 2009 19:04
Posts: 8

  Z3 roadster 2.8
Location: Derby

engine revving on its own

Post by Stevie64 »

Moved to correct forum - please read the instructions on the Knowledgebase! MF

Hi all, my engine on my 2.8 Z3 has just starting to rev on its own between 1750 and up to 2750 revs. Any ideas please. When warm it ticks over normally then goes into a mind of its own, up to 2750 and back down to 1750 revs. any help will be appreciated. Cheers
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Justin Time
Joined: Thu 22 Jun, 2006 20:34
Posts: 2183

  Z3 roadster 2.0
Location: Kent

Post by Justin Time »

Hi and welcome to the forum.

I suggest you try the search engine above as this is a well documented problem. Type in "unsteady idle", "cam position sensor", or "ICV" and click search for all terms.

Good luck.
BMW Z3 2.0L Velvet Blue Individual Edition
Stevie64
Joined: Tue 24 Feb, 2009 19:04
Posts: 8

  Z3 roadster 2.8
Location: Derby

Post by Stevie64 »

Thanks for reply. I think first port of call will be cleaning ICV
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SpunkyM
Joined: Mon 08 Mar, 2004 18:26
Posts: 1142

  M roadster S54
Location: Harrogate

Post by SpunkyM »

1) Clean ICV
2) Check for split hose / leaks
3) Replace cam position sensor.
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Gazza
Joined: Tue 04 Oct, 2005 20:58
Posts: 9521

  M roadster S54
Location: Romford Essex

Post by Gazza »

If all that fails.............................Exorcism !











:lol:
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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Ballie
Joined: Tue 16 Jan, 2007 19:03
Posts: 137

  M roadster S50
Location: walsall

Post by Ballie »

I had the same problem. Turned out to be my injectors. I had them replaced under warranty. Try some redex injection cleaner. Might help.
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Stevie64
Joined: Tue 24 Feb, 2009 19:04
Posts: 8

  Z3 roadster 2.8
Location: Derby

Post by Stevie64 »

Sorry for placing in wrong forum.
Just an add on to my original question, most of solutions seem to be for cold running problems, my Z3 runs perfect until it gets up to running temperature, and then the revs go crazy, I dont wish to sound ungrateful for responses, but i'm not to knowledgeable on mechnics of a car. Cheers
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Jonttt
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Joined: Sun 28 Dec, 2008 16:32
Posts: 6554

  M roadster S54
Location: Liverpool

Post by Jonttt »

Stevie64 wrote:.....but i'm not to knowledgeable on mechnics of a car. Cheers
Join the club :wink:

to quote Benjamin Disraeli "to be conscious that you are ignorant is a great step to knowledge". :rtm:
Happiness is not around the corner........happiness is the corner
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Robert T
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Joined: Mon 12 Jun, 2006 10:35
Posts: 10170

  Z3 roadster 1.9
Location: Cheshire

Post by Robert T »

Also have a check to make sure that the throttle is closing off properly - you should be able to operate the throttle linkage from under the bonnet (mind your fingers!) - if it is properly closed off, then I would expect to start looking at all the components that supply fuel air mixture - ICV, MAF, Lambda, injectors, and ECU. Cam position sensor would seem unlikely if it is running smoothly - this tends to cause uneven running (at best) and non-running (at worst).

The reason I suggest the throttle itself is as having had the carb and other ancillaries off my other car, I eventually found my sticking throttle was due to the extra bit of throttle cable catching and stopping the throttle returning to the fully closed position - the simplest things often cause the most head scratching... :head:

Cheers R.
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Stevie64
Joined: Tue 24 Feb, 2009 19:04
Posts: 8

  Z3 roadster 2.8
Location: Derby

idle

Post by Stevie64 »

thanks for responses. Cleaned ICV and TB No better. So I got Z3 on machine today. Came up 2 faults. 1 coolant temp sensor. 2 ICV. Recommended to try CTS first so ordered from BMW. Here's hoping!
phb10186
Joined: Sun 16 Sep, 2007 07:18
Posts: 383

  Z3 roadster 2.8
Location: London and Bournemouth

Post by phb10186 »

If it's not the ICV, then check it could be one of the leads running to it, or the airbox sensor.

Is the air intake ducting all ok? I had a 2 inch hole in mine when I took it out, and made the car run terrible.

ICV is the correct area to look


'Replace cam shaft sensor' the generic 'Fix-all' for BMW's
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Stevie64
Joined: Tue 24 Feb, 2009 19:04
Posts: 8

  Z3 roadster 2.8
Location: Derby

Post by Stevie64 »

WEY-HEY, BINGO, JOBS A GOOD-UN. Fitted coolant temperature sensor (less than £12 at BMW) 10 minute job. Had Z3 back on diagnostic, showing no faults, running sweet as a nut.
Thanks again for all responses, I was expecting a lot more than £40 and a bit of time to get it sorted
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