E34 Wild Idle!

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   Hello all
The idle speed on my 1991 E34 520i has progressively become worse over the last few weeks! A work colleague pointed me in the direction of the stabilising air valve(?), indicating that these are often a cause due to coking up. Tried cleaning it, but the problem returns...although it is intermittent, and not continually hunting. When it throws a tantrum, it hunts between about 1500 and 500rpm. Any clues?

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walnut146 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 16-March-2005 Status: Offline Points: 2	Topic: E34 Wild Idle! Posted: 16-March-2005 at 04:25
	Hello all The idle speed on my 1991 E34 520i has progressively become worse over the last few weeks! A work colleague pointed me in the direction of the stabilising air valve(?), indicating that these are often a cause due to coking up. Tried cleaning it, but the problem returns...although it is intermittent, and not continually hunting. When it throws a tantrum, it hunts between about 1500 and 500rpm. Any clues?

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J7 VNK Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Really Senior Member I Joined: 24-May-2004 Location: United Kingdom Status: Offline Points: 450	Posted: 16-March-2005 at 04:46
	Hi, Is the hunting permenant? hot or cold? have a look at this link for a few ideas! http://www.bmwe34.net/e34main/trouble/hunting_idle.htm item 6 is the ICV
	1999 528iA Sport Pack,Aspen Silver,17" MTech's. 1994 525i Sport, Avus Blue,SOLD (BMWCC Member) 1999 323i SE E46, Black, man, Sports Leather. My Cars "BMW's are for life, not just for Christmas"

walnut146 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 16-March-2005 Status: Offline Points: 2	Posted: 16-March-2005 at 05:04
	Hello The hunting is almost exclusively when warmed up, but not permanent. At times, it is rock steady.

J7 VNK Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Really Senior Member I Joined: 24-May-2004 Location: United Kingdom Status: Offline Points: 450	Posted: 16-March-2005 at 05:30
	Check for splits in the intake hose and all rubber pipes, squirt some aerosol around the intake and pipes when the engine is running (carb cleaner is best, you should have some if you cleaned the ICV) if the engine changes pitch (idles better) while squirting around all joints and the pipe itself then you can trace a leak! short term fix, electricians tape, long term, replace part. Just another option.
	1999 528iA Sport Pack,Aspen Silver,17" MTech's. 1994 525i Sport, Avus Blue,SOLD (BMWCC Member) 1999 323i SE E46, Black, man, Sports Leather. My Cars "BMW's are for life, not just for Christmas"

Phantom_Mark Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Senior Member II Joined: 21-September-2004 Location: Lincoln UK Status: Offline Points: 194	Posted: 16-March-2005 at 06:01
	I have just ordered a complete new pipe ( the large pipe from MAF to throttle body item#3 in the pic ) for around 10.75 ex vat from my local dealer, this was all broken and damaged around the lower connection for the pipe to the ICV ( item 12 ), I have taped it up in the mean time and replaced the ICV as a precaution, idle is now fixed on my car, I would strongly advise you check out your pipework first as replacing the ICV is a real pain in the **** due to the constrictive location under the inlet manifold. Mark. Mark, the reason you needed to space that word is the swear filter gets it, if the swear filter gets it you may take it that we don't want to see it ! Edited by Nigel
	<<<<< The only way is up >>>> ( unless your in a 5 series, then sideways is cool too ) 91' 525 24v Sport, Stainless Race Manifolds, PowerFlo Stainless + Decat, Big Bore Throttle Body, Viper 2 Chip + 17's, std BMW Air Filter :D

Jake Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 19-February-2005 Location: East Anglia Status: Offline Points: 82	Posted: 16-March-2005 at 06:15
	I usually go for a base idle and CO reset at the dealer. In the process they'll find problems that need fixing. Call it free troubleshooting. Jake

Phantom_Mark Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Senior Member II Joined: 21-September-2004 Location: Lincoln UK Status: Offline Points: 194	Posted: 16-March-2005 at 06:26
	How much do they normaly charge for that Jake ? And do I litraly just ask for a Base Idle and CO reset ? I think im gonna need some Diag from BMW to cure my current problems - they quoted 40 + vat for a diag session
	<<<<< The only way is up >>>> ( unless your in a 5 series, then sideways is cool too ) 91' 525 24v Sport, Stainless Race Manifolds, PowerFlo Stainless + Decat, Big Bore Throttle Body, Viper 2 Chip + 17's, std BMW Air Filter :D

e34-520iSE Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Really Senior Member I Joined: 22-December-2003 Location: Gateshead, UK Status: Offline Points: 453	Posted: 16-March-2005 at 19:04
	It's also a good idea to check your rocker cover bolts. If they are slack there will be air being drawn in giving a silly sort of brrrrrm brrrrm brrrrm idle. That happened to me when I put my rebuilt engine back in. I had every sensor, air/vac pipe off only to find I never tightened alll the rocker cover bolts - doh! Cheers, Shaun
	Self confessed madman 1990 Brilliantrot 2 ltr M20. Air force definition of explosives: A loud noise followed by the sudden going away of what was once there a second ago.

wildstar69 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 05-March-2005 Location: london Status: Offline Points: 5	Posted: 31-March-2005 at 20:40
	Hi I had the same problem with a E34 1991 518ISE that the idle speed was like a wiper blade going from 300 to 1500 rpm and sometimes the engine would conk out but on a few days it would idle regularly at a lower than normal idle speed with a bit of hunting but this was making driving untolerable. I was doing a lot of short inner city driving but after going full pelt to Scotland and back visiting my parents everything appears to be back to normall so maybe your 520 is a bit clogged up and a long fast drive might solve it.