Throttle body not working right

[hpbadger]

Well, I cleaned the dirty throttle body today and reconnected. Now it stays at high idle and goes back to low idle very slowly after I step on gas. Not sure what I messed up. I am going to reclean and reconnect. Does TPS or IAC have to be recalibrated? Thanks!!!!!!

[Ken]

From the book:

If the IAC valve is disconnected and reconnected with the engine running, the idle rpm may be wrong. In this case, the IAC valve can be reset by starting the engine momentarily and then turning the ignition key "OFF".

When servicing the iAC it should only be disconnected and reconnected with the ignition "OFF". This will keep from having to reset the IAC valve.

[hpbadger]

Originally Posted by Ken

From the book:

The IAC was off when the TB was cleaned. I cleaned the carbon off the TB carefully. Everything reconnected. When engine starts it stays at 1800 rpms and there is no response when gas pedal is depressed.

[Vettefan87]

Is the throttle llinkage bound up anywhere?

[hpbadger]

Originally Posted by Vettefan87

Is the throttle llinkage bound up anywhere?

No. It is responding to the pedal and moving...my mistake. I used wrong cleaner (carb cleaner ) on TB and figured I burned the TPS with the corosive cleaner. Swapped out TPS but that turns out not to be problem. Same high revs as b4 swap of TPS. Cleaned out gunk clogging vac port. Just idling way way to high on startup......Should have left well enough alone I suppose!

[hpbadger]

Originally Posted by Ken

From the book:

thanks Ken! I will reset the IAC tomorrow and see what happens.

[hpbadger]

I recleaned the TB using TB cleaner this time...it was still dirty, especially in the IAC ports. Got a new IAC and TPS. I went through the IAC resetting process and adjusted the idle set screw using a Dollar store screwdriver set that has a torx attachment. It fit perfectly. The IAC resetting process worked perfectly. I did not recalibrate the TPS. What I did wrong for sure was leave the IAC and TPS on while cleaing...won't do that again!

Now for the good news: The car now runs much better than before. Idle is much smoother and better throttle response . Cost me about $90 in parts but the IAC and TPS were probably origininal. I discovered that the old owner had set the idle way way high probably tocompensate for the dirty throttle body and IAC. Although frustrating and a little costly this was a great learning experience. Thanks a lot for all the input!!

[Ken]

[vetteboy86]

Great news, I am glad the vette is better. I am planning a similar project for this spring. I hope all goes well, but if it doesn't I will know who to call on for some help

Craig

[hpbadger]

Originally Posted by vetteboy86

Great news, I am glad the vette is better. I am planning a similar project for this spring. I hope all goes well, but if it doesn't I will know who to call on for some help

Craig

Let me know when you do it. I can definetely tell you what not to do. The plenum was also filthy. I started to remove it but ran out of time and didn't feel like removing the brake power assist fitting. I cleaned it as best I could.

[vetteboy86]

Can you take that fitting off of the brake booster first, to allow more wiggle room to get the plenum off? I am going to take my plenum off, and going to install a new one, that is ported. I still need to clean it, and clean the throttle body. I will let you know, mabe over spring break I will start on it.

Craig

[hpbadger]

Originally Posted by vetteboy86

Can you take that fitting off of the brake booster first, to allow more wiggle room to get the plenum off? I am going to take my plenum off, and going to install a new one, that is ported. I still need to clean it, and clean the throttle body. I will let you know, mabe over spring break I will start on it.

Craig

I think you have to take it off first. Not sure if I have the right tool to take it off...I'll see if I can get a wrench in there and let you know. What plenum are you getting? Is it aftermarket of do they port the stock plenums?