giosoccer20

I just isntalled a 65mm TB on my 95 GT 5.0, and after starting it, when it heated up, the idle went up to 2k and a little over, and the revs were hanging during gear changes. The car was running flawlessly beforehand, and now when i put on the Professional products TB it started doing this. I need help diagnosing the problem.

mattdel

Clearly its a vacuum leak, or the throttle plate is sticking.
Did you replace the gasket?

giosoccer20

gasket for what? i replaced the TB to intake manifold gasket and the IAC gasket. I dont know why there would be a vacuum leak all of a sudden, it was working fine with my stock TB. I think I might just have to adjust the idle adjustment screw? It's idling at 1500, then i unplugged the MAF sensor while running, and the car started idling at 600, almost stalling, then i plugged it back in, and it stayed at 600, until i gave it some gas again, and then it went back up to 1500.

mattdel

Try this:


Base Idle Reset Procedure

1. Clean TB with carb cleaner and nylon brush (toothbrush size). Engine off, fully open TB blade and spray/brush TB until all gunk and oil residue is cleaned.

2. Allow to dry, or close TB blade and start engine until it clears all carb cleaner fumes/liquid.

3. Let engine idle...if it doesn't, increase idle speed via TB stop screw until engine stays idling on its own.

4. Disconnect IAC valve, if engine dies repeat 3 with IAC disconnected.

5. Set idle speed to the lowest setting possible between 650-850 rpms with IAC disconnected. It is key to use the lowest possible to prevent idle surge, rolling, etc once the IAC is connected as follows.

6. Turn engine off, and reconnect IAC

7. With Ign On Eng Off, check TPS voltage output....if it's between .8vdc - 1.0vdc, it's OK. This voltage check should be done between the Green and Black wires at the TPS side connector as shown in the pic below (FYI: Green = TPS Signal, Black = SIGRTN, and Orange = VREF)....(-) terminal of the DVOM on the Black wire and (+) terminal on the Green wire.



8. Disconnect battery (-) for 3-4 minutes.

9. Reconnect battery, start engine, allow it to idle for 2-4 minutes to confirm setup,

10. If idle speed falls too low or stalls, increase idle speed via the TB set screw a little at a time.

11. Turn engine off for 20 seconds, re-start engine and repeat 9 - 11 if required.

12. Reconfirm TPS output is within the .8vdc - 1.0vdc range optimum range.

NOTES:

1. No need to reset ECM KAM (reset computer), the TPS minimum value used for idle control, is reset automatically by the EEC-IV every time the ign is cycled on-off for 20 seconds-on.

2. If the TPS output is within 6vdc - 1.1vdc, it's still acceptable, since no TPS failure codes will be generated, and it falls within the EEC-IV .5vdc - 1.19vdc working range.

13. Allow a 10-20 minute "relearning" period under normal driving conditions (drive cycle).....you're done!

giosoccer20

thanks a lot! car runs flawlessly now