Idle Problems

[Riry Jetta]

I have a problem with my E30 M20 idle. I changed my ICV to the new one but the idle position on the 1.800 rpm with 23 degree firing angle (using ECU computer monitoring). When I remove the ICV, the idle comes down to 700 rpm. Any idea to sets the opening ICV ? such as reprograming the ECU? :( :(

[SRR2]

Are you saying that the idle is high and out of control? If so, it's probably not the ICV, it's the Throttle Position Switch. You can check it with an ohmmeter.

Take the intake duct off the throttle body. Unplug the connector from the TPS. Connect your ohmmeter between the center terminal and the terminal to its left (Terminals 18 and 2, respectively. Yes, 18.). It should show continuity. Slightly open the throttle plate, and the switch should open. If you don't get continuity between those two terminals, you found the problem. To be thorough, check for continuity between the center terminal (18) and the one to its right (3). It should be an open circuit everywhere but WOT.

If you have a high-mileage car, especially with a manual trans, there's a good chance this switch will have worn out. The other thing that wears out and that can cause idle problems (but it's usually stalling and low idle, rather than high idle) is the AFM.