Adjusting Idle on TBI

[blazer_87]

I have 87 TBI. It seems to be running rich and idling high. cant find an idle adjustment. Is there one? Any advice??? thanks in advance

 

[TrcksR4ME]

All I know is that the idle is computer controlled on TBI, you cannot manually adjust it. I think there is some sensor right in the throttle body that impacts how it idles.

 

[kd7kmp]

The idle on a TBI truck cannot be manually adjusted. Idle speed is controlled by the Idle Air Control (IAC) valve which is in turn controlled by the computer. Sometimes the passage used by the IAC gets gummed up. Clean the throttle body with carb cleaner. That should help.

Kevin

 

[spearchucker]

Most of the time the throttle body gasket at the base is leaking. Spray some carb cleaner around the base and check if the idle increases slightly. If it does then just replace the gasket, simple fix.

 

[Emmettology 101]

Not sure about on a stocker, but on my holley there is a throttle stop screw that allows you to adjust the idle. It on the front of the TB right in front of the trottle bracket..... According to their directions you are supposed to unhook the IAC and then set it.

 

[dyeager535]

Instructions for setting idle are over on thirdgen.org in the tech section. IAC/TPS article IIRC

 

[blazer_87]

Thanks for the info on thirdgen.org. The passenger side of the TBI has two connectors, which one is the IAC? Thanks

 

[odee1]

the square on with four wires in it is the iac plug.

 

[Emmettology 101]

The IAC is towards the back of the TBI on the pass side. The connector in the middle is the TPS.