Reversed idle problems: 88 GL SPFI. hates me.

[PadreScout]

I'm back! I have been slowly whittling away at my new/old GL and have hit a bit of a wall, I replaced to the temp sensor and IACV because it idled MUCH too low when cold. I have created an interesting problem in doing so.

 

The situation:

 

When cold, the car idles low, around 500-700 RPM, wont start/ stay running without me keeping a toe on the gas pedal to raise the revs.

 

Once warm the car idles high. Like... 1500-2000 RPM high.

 

 

Now, by my reconning the car is doing exactly the opposite of what it should be doing. Do you guys have any idea what would cause this? I checked the search, but saw nothing that fits my circumstances. Thanks!

[dennyt]

My car used to do this ('94 Loyale SPFI). I fixed the low idle with the "sacred do not touch this" limit screw on the throttle body. I fixed the high idle by putting a restrictor plate in the IACV inlet line. I took a dime, drilled a 3/16" hole in it, and stuffed it in the 1/2" air line going into the valve. Now the IACV can't bump the idle up above 1100 no matter how hard it tries

[AKghandi]

Check the Intake piping for cracks or leaks if it's leaking it'll cause the low idle you may also want to check the Maf if it's acting funny it will cause this

 

Also check the timing it sounds like a timing advance problem explains why it runs crappy then idles too high

 

If you plug the test connector together it will stop the disty from advancing.

[AKghandi]

Oh I forgot to mention the coolant temp sensor connectors get corroded and give the ecu the wrong readings when I replaced my cts I had a cts code for a while till I fixed the corrosion and checks the wires