3-FE ISC idle speed control valve help please (1 Viewer)

[Mud taxi]

Hello, after first discovering that there was only one screw holding my throttle position sensor on, I adjusted it according to factory spec and put in a second screw. It idled at around 700-950 after that. (Used to sit at around 650). But I'm fairly certain I adjusted that correctly. Thought I'd test the isc valve considering I did have to take it off to access the bottom screw on the tps. (Thought I could have damaged something). The part tested okay I believe. Resistance was within spec and I got the valve to open and close by grounding out the terminals in sequence. But after the test I reinstall it to find that it now idles to around 2200??? I can't figure it out. Any ideas?

 

[red66toy]

When you reinstalled the ISCV did you make sure it sealed well? Maybe the 0-ring is bad and you now have a vacuum leak which is causing the high idle. Also, to get the best setting on the TPS, I found taking the throttle body off the cruiser and onto the bench gave me the best result. But that is just me. I thought I had it adjusted right but when I retested it on the bench it was definitely off by a little bit.

 

[E5corn]

I'm having almost the exact same issue, when I get home it's gonna be vacuum leak test time as mine is desmogged...
Biggest issue that's kicking my butt is the idle is spot on at times and 1500 rpms at times... ugh...

 

[RockDoc]

You could have a break in the wiring to the ISC valve if the valve itself checks out and it's seated. I had a wiring break once.

 

[Prairie Swamp]

To help with troubleshooting (for example vacuum leak versus electrical) do you have a way to see what type of command the idle valve is getting from the ECU? Meaning is it doing exactly what it's supposed to be doing.

For example if the water temp sensor is flaky it might be incorrectly telling the ECU that it's really cold outside forcing a fast idle. Just a thought.