Throttle body question

[Perseverance 11NW]

Hey all! I have an 87 GN. I recently installed a new iac, iac 45* angle boss on a new 70mm throttle body and a new tps. Im currently trying to get the isc and tps numbers dialed in. I feel like the throttle blade is sticking or something? Up to temp and in closed loop the rpm spins about 1050, if i push the linkage back it moves about 1/32” and idle goes to a nice 850. The adjustment screw is backed out all the way yet the iac still shows zero with the tps at 46. Any suggestions? Wanna get this thing on the road, thanx for any replies.

 

[1986 Buick GX1]

The adjustment screw on the throttle body is to raise or lower the IAC counts.
The engines idle speed is controlled by the ECM with inputs from IAC and TPS.
Here is some good info.

http://www.vortexbuicks-etc.com/basics.htm

Scroll down to IAC and TPS section or tap on the description for auto- scroll.

Here is another good one.

http://www.gnttype.org/techarea/faq/IACresetscan.html

 

[mikestertwo]

Throttle plate may be misaligned in the throttle body. I have seen this problem on a lot of aftermarket throttle bodies among other issues. IMHO unless you are running really fast the larger throttle bodies are a waste of money.

 

[Turbo6inKY]

Throttle plate may be misaligned in the throttle body.

This is probably it. It's crooked in the bore and won't close all the way. Take the throttle body off the car and move it to the bench. Back the throttle adjustment screw all the way out, then loosen the screws holding the throttle plate slightly, then cycle the throttle blade carefully a few times so the blade seats properly. Check it with a flashlight. It should be in contact with the bore all the way around. Then tighten the the blade screws. Put it back on the car and run through the adjustment again.

 

[Perseverance 11NW]

Ok I will try adjusting the blade. Thank u guys.

 

[Perseverance 11NW]

So it was an easy fix. The cruise control cable was adjusted too short (just barely). Lengthened it one notch and shes perfect now.