OK I just swapped in the TPI to my 79 Camaro. Runs great except the throttle is very stiff right at very beginning, and only when running. If the car is off the throttle feels fine, but if the car is running it's extremely stiff to crack the throttle. Once it starts to open it's fine again. I'm going to get a ticket. I keep spinning the wheels off the line because I end up mashing the throttle from a stop.

Can any one measure their pedal from the pivot to cable clip? That's the only idea I have.

Any suggestions, theories, or experiences you guys will share would be greatly appreciated.


Dave

 

It is possible that the throttle shaft is worn enough to allow the plates to bind in the bores once there is vacuum. You may be able to adjust the minimum air position stop screw enough to crack the throttle plates open a bit more (and allow a little less IAC air) to prevent this binding. As long as the IAC still has some control over idle RPM, you can get away with a slightly wider minimum air opening.

If you disconnect the cable at the throttle bellcrank and start the engine, you can verify this condition by trying to open the throttle by hand to check for the same sort of binding under vacuum.

If this is the case, you can live with the slightly higher minimum air position and readjust the TPS to compensate, or remove and repair the throttle body.

 

I'll try that. I did a fairly decent inspection on the throttle body when I put it together, but I certainly could have missed some thing. Will I feel the movement in the throttle shaft?

 

Vader, I do have a decent amount of movement in the throttle shaft itself. Your idea is the only thing that can make sense. No mater what the throttle body issue needs to be addressed. So who do you suggest for a replacement? The only ones available that I know about are BBK and Holley. What would be a good price?

Is there anyone that rebuilds these things?

 

Mine did this after I adjusted my "minimum air". I think the throttle plates were too far closed. I did exactly what Vader said, i cracked the blades just a littttle bit and then adjusted the TPS accordingly.

Everything is fine now.