[JcKore]

Hi guys,
Need some help. 94 Astro 4.3 Vin Z 106000 miles.
Fast idle issue and whistle or squeel noise. Replaced 3 vacuum lines. no change... Sprayed wd40 around TBI base gasket as much as I could get to, no change in idle but, inside of van facing engine. when I sprayed on right side of TBI I heard a change in pitch of whistle. Tend to think TBI base gasket is bad. Heard these were easy to replace. Question: Any explaination on the procedure to change gasket would be much appreciated.... Thanks guys.. Youv'e always been a huge help in the past! So little room to work with. Don't quite know how to proceed... Jack

 

[wmjwhite]

Shouldn't take more than 45 minutes to remove the throttle body and replace the gasket. I have an '87 but I think they are the same. You have to take off the air cleaner by loosening the wingnut, remove the air filter lid and rotate the z shaped rod that the wingnut tightens down on until it comes off, set the air filter and housing aside, and pull off the spacer that goes around the throttle body. Loosen up the two fuel lines on the back (use two flare nut wrenches and you won't round off or break anything) and disconnect the vacuum lines, throttle, cruise control, and tv cable linkage Check the fuel line O-rings, if they are bad, change them now. After that you need to unplug the IAC and TPS sensors. You should see three bolts (10mm I think) on the throttle body. One on each side and the third is dead center in the front. Loosen those up and the throttle body pops up and off. I stuff a rag into each side of the intake to keep junk from falling in and you can clean up the surface for the new gasket. With the TBI off, take a can of TBI cleaner and spray the underside to clean out those passageways in the throttle body. If they are clean, driveability improves dramatically. On the reinstall, the cleaner the intake the better and always use a new gasket, I usually add a drop or two of medium loctite to the TBI bolts and don't overtighten. (15ft-lbs max) I also would also check the PCV valve and its connections for leaks. The plastic on the tube and the elbows get brittle over time and can crack leaking vacuum.

Good Luck!

 

[JcKore]

Sorry took so long to get back on forum.
The TBI gasket did the trick! Thanks for all the help. You guys are the best...

Jack

 

[astro355]

Glad to hear everything worked out ok.