1992 BMW E36 318i M42 idle at 2000 when warm

[Dooscoop]

I need help diagnosing a high idle on a 92 318i. Its a manual 5 speed M42 1.8 4 banger and the idle is resting at about 2-2.2k. I have replaced the ICV, MAF sensor, coolant temp sensor, Intake boot, intake boot clamps, and ive put new temporary sealed hoses running from the boot to the ICV and from the ICV to the upper intake manifold. The car idles at 1100 (normal) when the MAF sensor is unplugged. It also idles normally when the ICV is unplugged, until i rev it, after that it rests at 2000 like it has been. The coolant temp sensor's wiring is quite shoddy if that makes any type of difference. I cannot run a stomp test due to a bad gauge cluster/ computer (im not sure because i have not bought a new cluster yet, im assuming its the cluster although all of the other gauges work properly except for the engine temp sensor which does not move from the left most position.) Any ideas or questions are appreciated!

[Eric93se]

Well when you unplug the IACV and then rev the engine and then notice the idle is higher, this is probably a normal reaction because the valve inside the IACV probably swung open.

So other possibilities, test the throttle sensor (TPS throttle position sensor) check the resistance and that it varies across it's range (look up the values). Also, with the car off, pull the throttle valve open and let it slam shut (spring loaded), check by pushing on the throttle valve that it is in fact shut. If it's not closing then it could be a bad throttle cable, they wear out because of the plastic jacket, and lubing it may or may not help.

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Other possibilities, you might want to pull your DME and open it up, check for oxide tracks.

[Dooscoop]

I don't think the TPS is the problem because the idle does not really vary too much and the car isn't stuttering at all. I think a bad BME is possible and i plan on replacing it soon. What is a good tell for a bad throttle cable, it seems to be sitting like it should and reacting to the pedal well.

*edit* How can i diagnose a bad DME?

[Eric93se]

Open up the dme, get access to both sides inside, check for oxide tracks. You can post high res pics here if your not sure. You don't have enough posts here on the forum so you can't use the forums host, but you can use another free pic hosting site.

[Dooscoop]

Is there anyway to reset the DME i have? if its the DME that is causing a high idle i could take it out and reset it if possible.

[Eric93se]

For your year you can unplug the neg on the battery and leave it off for 10 min. You can search the forum for better instructions. I doubt that will fix anything though.