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Old 05-05-2021, 02:45 AM   #7
Otto Mattik
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Join Date: Dec 2015
Location: Upper Midwest more or less

Originally Posted by ITA View Post
I just changed the coolant temp sensor (fuel injection sensor) and the coolant temp sender sensor. I had a constant idle of 1500 rpm regardless of whether the engine was cold or warm and my temp gauge was not working.

I removed the intake manifold and cleaned the TB and replaced gaskets. After I put it all together, it surges terribly at idle, going to to 1500-2000 rpm and dropping until it almost dies and up again. Each interval lasts about 2-3 seconds. I do not understand what is happening. I checked all the hoses, sensors, and grounds I undid, and I didn't miss any. I did mess up the ignition coil wire (the wire came out of the boot on the distributor end; I can stick it back in, but I don't think it should be that way). What should I be looking at? Bad IAC all of a sudden? Bad TPS (it seems adjusted correctly)?
In your initial post you mention a constant idle of 1500, and the surging began after replacing the CTS ?

My only experience with a bad LH 2.2 IAC was one that idled too high, and it was worse when the engine was hot. Like I mentioned on mine, it was within spec, cleaning made no difference and the problem only went away after replacing the unit. It's also very possible the issue has nothing to do with your IAC, mine never surged, it only idled high.

The video shows how do a resistance test on the IAC(it's a good place to start).

I assume you have not changed the timing ?

Also not sure if you're aware of this detail, but do not disconnect computer related components with the ignition on. Turn engine off, turn key off prior to disconnecting/connecting electronic components.

Desperate need of elf assistant for interior work - Cash/Beer option $

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