Help setting idle! At witts end!

[dimeified]

I've jumped the test sockets to center the ICV throughput after i pulled it from the car and cleaned it real well. As i have the test sockets jumped, i set the idle to 880. This is with the car fully warmed. Once i remove the jumper, the idle drops below 750. Good news is that the hunting idle is gone, but the bad news is i can never get the idle to match with and without the jumper in place. The idle is ALWAYS lower with the jumper out, no matter what i set it to when its in! Please help. Am i forgetting something?

[ZOA NOM]

CO mixture must be correct before any other settings are adjusted. Get the mixture set with a gas analyzer.

[john walker's workshop]

how about setting it to 880 and forget about the jumper?

[ZOA NOM]

The jumper bypasses the ICV, so leaving it out causes his problem. Can you feel the ICV valve rock back and forth in your hand if you remove it? It should move very freely. When it's connected, it should hum slightly.

[dimeified]

I would not think the icv is damaged. Once i cleaned it, and set the idle with the jumper method, it doesn't hunt anymore on cold startup. By the way, the arrow on the icv is supposed to point DOWN, correct? It's beyond me, why if i I set the idle at 880 with the jumper in causing the icv to return to it's neutral position, that when i pull the jumper, the icv would try to bring the idle down? To be in the ballpark of 880rpm, the tach needle needs to sit about half way between the 750 and 1k tach lines, correct? I dont mean to sound like a moron, but i always assumed the tach lines under 1k were 250 500 and 750. If i'm wrong about that, it could be a simple mistake of misreading the tach and i could be causing my own problems.

[ZOA NOM]

Yes, the arrow points down. I suppose the only way to be sure about the tach is to use another method of seeing rpm, but mine idles just below 1k, so I think you're in the ballpark. The ICV is only a metered air device, so it's apparent that it is closing off some of the air when you remove the jumper. I'm still not convinced that your CO mixture is correct. The CO mixture screw is also a simple air metering device located on the AFM, and should allow you to compensate for the change in the ICV.

[dimeified]

i am going to look into the co mixture... good idea.