I suspect a vacuum leak on my '86 MAF 305 TPI. I've heard to take a propane torch without igniting it and blow propane around the intake to target the leak when you hear the idle surge, but gee, sounds like a boom boom situation if ya ask me.. Ive used starting fluid at the base of a carb on an old car to find a vacuum leak, but i dont like the mess.

Im wondering if someone can tell me a better way they know of to target the location of a vacuum leak on the TPI. Much appreciated!

Thanks

 

I've used propane before and didn't have any problems. I wouldn't use it for a long period, but for a few seconds, it shouldn't be a problem.

Water in a squirt bottle will work.

A section of hose with one end in your ear will allow you to "listen" for a vac leak near the other end of the hose. I have a hose with a 12" piece of alum tubing on the "probing" end. The tubing can be bent to get around things in tight places and around corners.

I'd stay away from using any flammable liquid to look for vacuum leaks. I watched a buddy catch a customers car on fire using B-12 carb cleaner.

 

ok thanks. maybe the propane isnt as bad as i thought, i was worried about arcing from pug wires or anything like that, although everything should be good and newish.

the sound through a tube is the kind of thing i havnt thought of, its worth a shot tongiht when i get home!

thanks again

 

I've seen fires from using starting fluid and I've seen propane gas flash before, neither of which I'd like to see again.

Use a spray bottle with a mixture of soapy water. It won't harm anything, and its safe.

 

soapy water? are you looking for bubbles or are you looking for the engine's idle to change?

 

if your checking for vacuum leaks, your listening for the idle to change..