I have a high idle problem I am still troubleshooting. I have rebuilt the carb and even tried a different carb and I still idle around 2000 in park. I have read several post which state to look for vacuum leaks. What is the best way of going about that?

Can I hook up a vacuum gauge? If yes, what places and what readings should I get?

86 z28 305H/ rochester quadrajet/Automatic/

Any help would be greatly appreciated.

Thanks,

Rob

Pinch off vacuum hoses one at a time with a pair of pliers. If it's a leak somewhere far from the engine this will find it. Otherwise, spray around here and there with carb cleaner and see if the idle picks up. If there's a vacuum leak it'll rev up when you spray near the area of the leak.

2000 RPMs is awful high for a simple vacuum leak (unless it's the power brake booster hose leaking). Sounds more like the choke isn't getting all the way open and is hanging on the choke's fast-idle cam.

I think I have multiple problems. I believe the choke was bad also. But I have the identical problem with 2 different carbs. When I close the choke manually the idle decreases but shouldn't the engine die with no air? Thats why I believe their is a vacuum leak. When choke is closed the engine runs like crap but its still getting air somewhere.

Having to much fun.

Thanks,

Rob

Could very well be. If you manually shut the choke plate all the way it should go so rich it dies.

The choke could be good on both carbs but if it's not getting 12V to the single wire that supplies voltage to the choke heater on the pass. side of the carb (check with key in "on" position) it won't warm up, the choke won't open and the idle will remain high.

Thanks for the help.

I found a leak on the Vac line coming from the pcv to the carb. Capped one end off and idle dropped to around 1000. I drove car around for awhile and it seems ok. Have to drive around for a litttle longer to verify though.

Again thanks for the info.

Rob

You can check for vac leaks by spraying carb cleaner by the suspected leaks. If you spray an area and the idle changes you can be sure the leak is also there. Good trick.