redneckandy

whats the best way to find vacuum leaks?

camo31_10.50

take some carb cleaner and spray it allll over the vacuum lines and anywhere ya like..if ya got a leak..then your idle will stumble a little bit..or in my case it will idle up a bit?

you can also use starting fluid..lol

shaeff

Yep, that's what I do. When you find the leak, the idle will raise because you're essentially giving the motor more fuel.

camo31_10.50

well i think it works more along the lines of you're simply "closing" the hole for a second or 2.....cuz if ya spray a little carb cleaner into the carburetor..then it stumbles.YA DIGG!?!? lol

sorry.....had a little..uhm..moment there..HAHAHAHAHA

DupermanDave

I took a lot of water and just poured it over the engine. You'll hear hissing when you find it.

shaeff

Maybe on your carb'd truck. Though on my old '71 Chevy (carb'd) I used the same trick with great success. On an EFI vehicle, when you spray carb cleaner or any variant thereof on an intake leak, the idle will smooth out and raise as if you're pressing the accelerator pedal.
Yeah, don't do that. LOL.

DupermanDave

Pouring water over mine was the only thing that worked. The carb cleaner/propane/wd-40 ideas don't work too well. If it's a vacuum leak, it's only going to get sucked in and burned off.

shaeff

That's the whole point! When it gets sucked in and burned, the idle speed changes. I've NEVER had a problem locating a vacuum leak in this manner. Ever.

broncbob

Best way I have found is propane or map gas. Turn the lil torch up ALL the way and start moving it around to the places that can leak. Don't move it to fast, give it some time to get into the the works and speed up the idle. Don't forget to check where shafts go through the carb/throttle body and the base of witch ever you have.

jimep

I've tried the carb cleaner, propane, buetane, map gas, starting fluid methods before and usually got mixed results. Way more often than not they didn't work. The way that worked 100% of the time but is a little more dificult is to cap off ur intake and exhaust and pressurize the whole system w/ 5 to 10 lbs of air pressure. Spray everything down lightly with soap and water and look for the bubbles, just like checking for leaks in a tire. Works great at finding every leak including exhaust leaks.... some garages are capable of using smoke to check for them, not sure how good it works, haven't seen that done... mayby next time I'll just borrow the vacuum leak finder from my work and test it out. It does a decent job finding vacuum/air leaks on our evaporators.

shaeff

^ Smoke machines work great too. They've got one at my friend's shop.

buckz6319

X2 on the smoke machine what a Great Idea and well worth seaking out one