BBK 58mm throttle body idle issues
 

Well ive search numerous other threads on this and have also found plenty of helpful info but Im still having issues.

Ill start with the problem first.
Car starts with NO issues and drops idle to about 800-1000 rpm (cold start) quickly. Throttle response and blips of the throttle is NO problem for the first 15-30 seconds. Then when it hits a specific time frame idle climbs to approx 3000rpms and hangs there. It will not drop.

Now the basics.
- intake mani was gasket matched and there is no throttle blade interference.
- I set the TPS to .50 vdc as stated in multiple threads I read. (some I read .5 and some I read .54 but its plus or minus .07 so either way Im in the clear.)
- Checked all my vacum conections and made sure that everything is nice and buttoned up.

Oh yeah and I just went out to the car real quick and just noticed. The throttle blade arm that attaches to the throttle cable isnt touching the throttle stop? Is that normal? Is there a way to adjust the length of the throttle cable?!!?!?!

http://i41.photobucket.com/albums/e2...an/intake1.jpg

http://i41.photobucket.com/albums/e2...an/intake2.jpg

http://i41.photobucket.com/albums/e2...an/intake3.jpg

http://i41.photobucket.com/albums/e2...an/5vdcbmp.jpg

What am I missing? Anyone with any experience with this issue?

Thanks

Oh yeah 1993 lt1 6spd.

Need to scan it and get the IAC counts and what the computer thinks the throttle position is at idle. If it thinks the throttle is part open, it will command the IAC to open further. I used to reset the TBI trucks by unplugging the TPS, turning the key on, then off. Plug the TPS back in and start the car. Might work on a 93 LT1 since that has the old style ECM.

Ill give it a shot thanks.

Yeah if you can see what the IAC counts and TPS volts are when the problem occurs, it should help. The big problem is they don't isolate the idle air from the plenum air. Your idle issue sounds like something else is going on as well.

It was because the throttle cable is too short. I disconnected the throttle cable. re-adjusted the TPS and fired her up. Idled reved and acted completely normal.

Is there an adjustment on the throttle cable length!? If not I am just going to ovlong the holes in the throttle cable bracket and move it closer to the TB...

The black plastic thing in the middle of the cable that goes to the traction control unit is the adjuster.

I dont possibly see how the cable would be adjusted from there I just went out to the car to take it apart and the cable just runs through it. I think there is a procedure in the FSM but I dont have one... Ill have to do a couple more online searches...

Just looked it up on alldata you are right. It adjusts the length of the plastic "sheeth" that the cable is in.

Cool thanks for your help man!

Hope this fixes it! Ill have to try it after work when I get home.

Thanks again!

Just got home and now I got the cable adjusted so the fulcrum hits the stop!!!! But now........ Pedal at WOT the blades only open about 75-80%............... Seen someone else say something like this and saw the way they fixed it. Seemed a bit shade tree but it worked. I may atempt a similar idea but with a little more thought behind it...

Are you sure you bought the correct throttle body for your vette? There are a few different part numbers out there.

Yes I had the wrong one at first. Then sent it back to jegs and recieved the right PN TB! :D