high idle when engine is in traffic - The Unofficial BMW M5 Messageboard (m5board.com)

Grannyshift · 30th October 2009, 04:39

Hello Gentlemen,

you guys have been a golden resource, cant thank you guys enough

Toronto's traffic is a mess - no matter what day or time - it's always a nightmare.

When my car sits in traffic for quite sometime - the oil will get to about 90 degree's Celsius [and the engine temp stays at center] and after driving it and bringing it back to idle it will rest at 1250 rpm - to about 1500 rpm.

If I give it a good rev - usually 3000+ it'll come back down to 1000 rpm or just slightly less.

does anyone know why this happens? I use sunoco 94 premium...

Blitzkrieg Bob · 30th October 2009, 04:55

My wife had the same problem with her Touring....Check your floor mat to see if it has creeped up against the pedal.

Konfused Pete · 30th October 2009, 07:57

Throttle bodies linkages might be sticking and could need a clean. or perhaps the same with your idle control valve. Have a friend with a E36 M3 and it used to idle at about 1500rpm also until we took out the ICV and gave it a clean.

mottati · 30th October 2009, 16:26

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Does it matter if ac is on? I had a bad throttle switch (at the front of the engine/ throttle linkage) which kept the revs up near 2k when hot with ac on.

91e34M5 · 30th October 2009, 16:49

I tend to agree with previously mentioned sticking throttle linkages. Check your cables that they are working freely and that your mechanical linkages are not binding.

davidoli · 31st October 2009, 18:07

As Mike mentioned , Throttle Position Sensor ( TPS ) is a possible suspect .

Are you able to get a diagnostic check done ?

D

ramsing · 31st October 2009, 18:37

Quote:

Originally Posted by Konfused Pete

Throttle bodies linkages might be sticking and could need a clean. or perhaps the same with your idle control valve. Have a friend with a E36 M3 and it used to idle at about 1500rpm also until we took out the ICV and gave it a clean.

+1 on this. I was having the same problem as Grannyshift, I just cleaned the linkages with WD-40 and its gone away. Revs up and down nicely now. Try cleaning first, before looking at the ICV. I just changed mine about 3k km's ago.

Adjusted the AFM against the CO2 readings, and its so much smoother now.

Grannyshift · 2nd November 2009, 20:20

Quote:

Originally Posted by ramsing

Adjusted the AFM against the CO2 readings, and its so much smoother now.

whats the AFM and how do you adjust it?

and I'm gonna give her a good spray tonight - you see, she's fine all the time, except traffic and when the oil is 90 degrees c.

on my way home from a long road trip, I was driving at 140 km/h and the oil stayed at a cool 70 degrees c.

would it be safe to run to red line when the oil is at this temp?

Lantz · 2nd November 2009, 21:56

Your engine runs very cool (assuming that your oil temp meter is working).

Mine usually sits at around 90-100 regardless of how I drive.

Grannyshift · 2nd November 2009, 22:30

could it be the cold weather and high speed?

i only ever reach 90 degrees IF im stuck in traffic - i dont ever remember seeing it go up to 100...