92ehatch

Ive wanted to do a vacuum leak check with smoke on my truck for a while now since I've been trying to track down some odd idle issues since my rebuild. I've tried the water, carb cleaner etc and never found anything useful. I was sitting on the couch vaping and thought to myself, hell i have all the stuff i need right here.

For those of you who do not know, vaping is an alternative to smoking. It's essentially a fog machine, using a heater coil, wicking, vegetable glycerin, propolyne glycol, flavoring and nicotine.

From all of that you really only need the vape and vegetable glycerine. You either already vape or know someone who does and can probably do this yourself.

what you need (what i used):

air compressor
regulator
​​​​​​blow nozzle
flash light
vape
plastic film (needs to be somewhat strong)

your blow gun needs to have a rubber tip like this harbor freight guy




First step is disconnecting the air intake tube from the throttle body (I'm not explaining or showing this)

next take the plastic you have and wrap the throttle body with it (one piece, unfolded) put your intake tube back on, over the plastic, and tighten.

I used shrink plastic from my work (we are a bottle facility) if you buy bottled water, you have this or can get it easily
next you need to set your air compressor regulator really low (like .5 psi)

So low it wouldn't even register, i used my ear to tell me i had flow

Now disconnect your air line (mine is 50ft) from the air compressor, push the lever on your blow gun, and using your vape (or friend, or fog machine) fill the air line until it comes out of the other end. The longer the hose, the better.
​​​​​
attach the line back to your compressor and then put your blow gun on the valve cover vent tube. You may have to repeat this several times to get the fog thick enough inside the intake
​​​​​​




Now just push the lever on the gun. You will barely hear the pressure release from the gun but since you know you have a very low pressure flow (you tested it with your ear right? ) it will slowly fill into the intake manifold and pressurize it. You will also hear your plastic bubble out. To much pressure and it will rupture.

now take out that nice bright flashlight and watch carefully.

Oh looky there, a leak. Fixed with new o ring. Picture does not do this justice, it was a steady stream
The only other place i had it coming out was through the crank case breather port. I have a new oem pcv valve so either it leaks slighly, valve guides, or rings leak a hair but i don't know how bad that would be.



hope this helps someone, enjoy

Co_94_PU

iTrader: (-1)

Less work to just pump the air through the "fog machine", think ziploc and some tape would do.

PCV doesn't look like my all metal Toyota part, from here.

Other wise sweet effort glad you found some problems you could fix without having to pay 120$/hr

92ehatch

I ordered that pcv through 22re performance with a few vacuum lines grommets t stat etc. The pictures on their site shows a silver metal but mine is black metal. Came in a yota box.

to follow up, i performed a leak down test on all cylinders. All 4 had 98psi (or 2%) leak down with the only air escaping at the valve cover. Cold engine test. So chances are the fog coming though the crank case breather was just flowing passed the rings.

Melrose 4r

Very cool. I am familiar with the old cigarette smoke method. Vapor clouds seem to be more concentrated than cigarette smoke. Where was your leak- it looks like the cold start injector, maybe?

92ehatch

Small o ring on the ac idle adjustment screw.

coryc85

eHatch - pretty cool way to find vac leaks. I was reading your other thread and I wondered "How did he find a small vac leak" and then I stumbled on this thread, glad you explained it, gotta love the ingenuity. I was not aware that idle up adjustment screw had an o-ring on it, I might have to change mine just for the heck of it.

Melrose 4r

i read in another thread and wrapped mine with some teflon tape.