Idle Control Unit?

[purrfektrs]

i'm on my last hope for my 87 325es. the idle is all types of messed up.. so i was told to replace the idle control unit. i know its in the glovebox, but is there anything i need to know when removing it? a friend let me borrow his good one, so im hoping that itll fix the problem.

and what exactly does the damn thing do? ive done google searches and nothing has really been mentioned about the unit.. so, now im asking you guys


any help would be awesome

thanks!

[Andy.B]

If it runs OK other than idle, and you have ruled out vacuum leaks, the most likely culprit is the idle temp switch (a coolant sensor that controls the isle circuit) or a faulty module. The module itself is green, and held in with one 10mm bolt next to the DME. There is a list of tests in the Bentley for the idle system. I recommend doing them until you find the problem.

[Andy.B]

Afaik, some of the earliest modules were likely to be faulty, but were most likely replaced years ago. I believe that if it's a green unit, than it is the update version, but I'm working from memory on that.

[Andy.B]

And finally, if you determine that the middle itself is the problem, I have a recently tested and known good unit for sale.

[purrfektrs]

Dme Is what ? In full word terms

[Andy.B]

The DME is the Bosch term for the engine control computer, or, ecu.

[Andy.B]

It is the larger, silver box above the glove box. The isle control unit is the smaller green one.

[Andy.B]

It sounds like you don't have the Bentley manual. I cannot stress enough how helpful it will be to read it, and follow the diagnosis steps for the idle system. The manual is available online for free as a PDF. You really should buy one, but the PDF is out there...