Vacuum Leak?

[05_GTO]

This issue has been getting worse and worse. It's an 89 with the carbed motor. The car has always idled like crap, if you give it a little gas it smooths out. However with the AC on it gets worse, to where it almost dies when the compressor kicks on and off.

Now I'm thinking this could be a vacuum leak, what is the easiest way to check for these... just looking for cracks in the lines? Another thought is that it could be the carb? Either the idler screw needs to be adjusted up or it needs to be cleaned/rebuilt.

[TonkaTom]

First things first look for hoses that have disconnected, maybe you have taken something off in the past. Also the idle could be set too low.

[eage8]

usually with vacuum leaks it makes it idle higher.

I would first clean your carb really well with carb cleaner if you haven't recently. Then adjust the idle screw and if that doesn't work you can adjust the idle mixture screw.

[toyotaspeed90]

maybe the a/c Idle up isn't working?

you can generally find vacuum leaks by spraying some sort of brake cleaner around vacuum lines -- if the idle bumps up you have a leak (the fluid is combustible and acts as if you added fuel)

[90 GP]

The idle boost up when the a/c kicks on is adjustable. I can't remember if it's the throttle positioner ( dual vac unit) on side of carb that controls it or a separate cam on same side of carb . Try checking with engine running and a/c off and have someone switch it on and look and listen to see if a cam or vac unit link moves as well as listening for vac leaks. There should be an adjustment screw on the cam and there is one on throttle positioner. I don't have a pic to reference and it has been 20 yrs. since I had the carb setup so going by memory.

[05_GTO]

Well I know nothing about carbs, so this shall be interesting lol.

[eage8]

Originally Posted by 05_GTO

Well I know nothing about carbs, so this shall be interesting lol.

If you get fed up with the stock carb... I have a Weber 38 DGES kit for sale