91 E34 525i Help - Car Revs High when Heat or AC is on.

miniata · Post by **miniata** » Fri Dec 29, 2006 6:11 pm

Every time I have either the AC or the Heat on, my car revs are high as I push the clutch in and shift through the gears, and when I'm coming to a complete stop, it takes a few seconds for the car to stop reving. Does anyone know what might be the cause.

ThumpersGP · Post by **ThumpersGP** » Fri Dec 29, 2006 8:24 pm

Of course there could be several reasons for that such complaint. for that vehicle with a NON vanos engine , i've change quite a few ICV's(idle control valves) . they generally build up with carbon and get stuck. sometimes removing,cleaning,and reinstall does the trick. it is also free.
any ECU codes(check eng light on?) ,check to be sure the floor mat is not resting on the gas pedal , throttle position switch could be faulty are other possibilities

HTH

miniata · Post by **miniata** » Fri Dec 29, 2006 9:03 pm

ThumpersGP wrote:Of course there could be several reasons for that such complaint. for that vehicle with a NON vanos engine , i've change quite a few ICV's(idle control valves) . they generally build up with carbon and get stuck. sometimes removing,cleaning,and reinstall does the trick. it is also free.
any ECU codes(check eng light on?) ,check to be sure the floor mat is not resting on the gas pedal , throttle position switch could be faulty are other possibilities

HTH

No ECU codes appear and the floor mat is stationary. My floor mat is in excellent condition and dosen't glide like on my Mom's 5. I'll have to look into the ICV's. I believe I changed them once before. I'll have to look through my records.
Thanks

victory1auto · Post by **victory1auto** » Mon Jan 01, 2007 8:19 am

Mini,

Given that you only experience the problem with the AC or heat on, I would suspect the idle-control valve [ICV], as they are fairly problematic on your E34. As Ray suggests, it could be other things, but the first place I'd look would be the ICV.

Regards to 'Liv....

-Vic

miniata · Post by **miniata** » Tue Jan 02, 2007 3:27 pm

victory1auto wrote:Mini,

Given that you only experience the problem with the AC or heat on, I would suspect the idle-control valve [ICV], as they are fairly problematic on your E34. As Ray suggests, it could be other things, but the first place I'd look would be the ICV.

Regards to 'Liv....

-Vic

The problem has temporarily disappeared. The car has not been driven in over a year, and perhaps it needed to get some kinks out as I recently started to drive it again.

Where is the ICV located? I tried looking it up in my Bentley Manual and couldn't find it!

Liv sends her regards to you as well.

ThumpersGP · Post by **ThumpersGP** » Tue Jan 02, 2007 4:24 pm

the ICV is located just below the 3rd and 4th intake runners. look thru the small rectangular openings and you'll see the black/silver valve.to get to it,removing the air box,intake boot,and for some people remove the throttle body to make it easier to access.

due to a older car,be prepared to replace the inlet/outlet hoses to the ICV along with a stubborn adaptor located between the intake manifold and the upper(outlet) hose to the ICV.

sorry ,i do not have any pictures at the moment. maybe someone in the club has pics(Vic??) .

HTH

miniata · Post by **miniata** » Tue Jan 02, 2007 4:47 pm

ThumpersGP wrote:the ICV is located just below the 3rd and 4th intake runners. look thru the small rectangular openings and you'll see the black/silver valve.to get to it,removing the air box,intake boot,and for some people remove the throttle body to make it easier to access.

due to a older car,be prepared to replace the inlet/outlet hoses to the ICV along with a stubborn adaptor located between the intake manifold and the upper(outlet) hose to the ICV.

sorry ,i do not have any pictures at the moment. maybe someone in the club has pics(Vic??) .

HTH

Yes, I did read about the hoses when I was doing the research on the ICV. I also saw a very small picture of what it looks like but a Diagram would be extremely helpful.

Was not aware about the adaptor

thanks Ray for advising me about this.