Hi idle and surging

87 m20 2.7, Engine idles hi when started cold then surges when warm. The problem is working out if its the idle solenoid or the power supply to it thats at fault. We do have 12v at the plug to the solenoid but the valve doen't operate. When i pinch the hose to the valve the idle speed can be mantained. I have checked all the sensors and they all test up o'k. I have tryed to measure current draw to the valve but cannot get a reading. Has anyone had this problem and cured it. Are there any other tests i can do on the wiring side to diagnose either the valve or the computer. Have spent hour trying to find a vacuum leak to no avail. any further ideas would be great. cheers.

Have you removed the idle valve and cleaned it thoroughly? Sometimes that's all that's needed.

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Archeo-peteriX
Have you removed the idle valve and cleaned it thoroughly? Sometimes that's all that's needed.

When your motor is warm does it race when you first start up?

Alot of shops replace the idle control valve and the module that controls it that's located over the glove box, the guys here don't usually go along with that theory though.

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rkj

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Archeo-peteriX
Have you removed the idle valve and cleaned it thoroughly? Sometimes that's all that's needed.

When your motor is warm does it race when you first start up?

No it doesn't and it shouldn't. If the ICV or the control module are not working it might do that.

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Alot of shops replace the idle control valve and the module that controls it that's located over the glove box, the guys here don't usually go along with that theory though.

We don't advocate replacing parts to solve problems; we troubleshoot them down to one or two items then repair or replace as necessary.
Simply chasing a problem by replacing parts is costly and unnecessary.

In the case of the Idle Control Modules; there were some issues with bad solder joints. Many simply resoldered the boards and the problem was solved while others replaced the modules...all after establishing that this was the problem

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Archeo-peteriX

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rkj

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Archeo-peteriX
Have you removed the idle valve and cleaned it thoroughly? Sometimes that's all that's needed.

When your motor is warm does it race when you first start up?

I was asking that because the cause of this condition is the coolant temp switch on the head on the eta

No it doesn't and it shouldn't. If the ICV or the control module are not working it might do that.

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Alot of shops replace the idle control valve and the module that controls it that's located over the glove box, the guys here don't usually go along with that theory though.

We don't advocate replacing parts to solve problems; we troubleshoot them down to one or two items then repair or replace as necessary.
Simply chasing a problem by replacing parts is costly and unnecessary.

In the case of the Idle Control Modules; there were some issues with bad solder joints. Many simply resoldered the boards and the problem was solved while others replaced the modules...all after establishing that this was the problem

Most people won't go through the trouble of opening these units Peter, I don't think- That's for techs like you, and the more advanced guys here I look forward to your letters



Edited 1 time(s). Last edit at 03/06/2011 05:30PM by rkj.

Rick, didn't you take your toys apart when you were a kid?



alan

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alanrw
Rick, didn't you take your toys apart when you were a kid?



alan

God yes. but that was before solid state

Rick,

Soldering a circuit board is the equivalent of putting another turn on a bolt/nut...different tool; same result

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Archeo-peteriX
Rick,

Soldering a circuit board is the equivalent of putting another turn on a bolt/nut...different tool; same result

Peter, Thanks for that. I've just never felt comfortable in there. If I could just fix one and have it come out right I might get over it!

Cheers

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rkj

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Archeo-peteriX
Rick,

Soldering a circuit board is the equivalent of putting another turn on a bolt/nut...different tool; same result

Peter, Thanks for that. I've just never felt comfortable in there. If I could just fix one and have it come out right I might get over it!

Cheers

Think about it this way...if it's broken, you can't make it any worse and you might fix it. Worst case scenario is that you end up replacing it

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Archeo-peteriX

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rkj

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Archeo-peteriX
Rick,

Soldering a circuit board is the equivalent of putting another turn on a bolt/nut...different tool; same result

Peter, Thanks for that. I've just never felt comfortable in there. If I could just fix one and have it come out right I might get over it!

Cheers

Think about it this way...if it's broken, you can't make it any worse and you might fix it. Worst case scenario is that you end up replacing it

And there you are; prospective and context. I'm set!

Hi
Just thought I would say that I had the very same problem and it took me for ever to finally track it down. After changing all kinds of things including the ECU. The air idle control valve and its computer.
!
!
!
!
!
Thought I would keep you hanging for a min.
It finally turned out to unmonitored air feed from the intake manifold gasket. The tiniest air leak caused me a major headache, but once I changed that thing my car started to run just
GREAT. No problems since.
Peter L
PS I Own a 1986 BMW 325e



Edited 1 time(s). Last edit at 05/27/2011 05:40PM by lawford1.

Had the same problem, turned out the oil dipstick wasn't seated!!!!! Seated it, problem solved.

alan