How to find a vacuum Leak [Archive] - Chevy Nova Forum

: How to find a vacuum Leak


tnblkc230wz
25th-April-2010, 08:46 PM
I got my EZ EFI installed and I believe I have a vacuum leak. I'm hoping it is the throttle body gasket because I reused the the gasket from my Holley. If it is not, what is the best way to find the leak without using ether?

mrtimstik
25th-April-2010, 08:48 PM
Spray tiny shots of starting fluid in spots you suspect the leak with engine running. Listen for a rev.

tnblkc230wz
25th-April-2010, 09:36 PM
Spray tiny shots of starting fluid in spots you suspect the leak with engine running. Listen for a rev.

I was hoping there was a better way than ether.

infotom
25th-April-2010, 09:40 PM
I have a propane bottle with a 3' hose and a needle valve so you can control flow. just crack it open and point in suspected ares, Or carb cleaner with the straw.

tnblkc230wz
25th-April-2010, 09:47 PM
I have a propane bottle with a 3' hose and a needle valve so you can control flow. just crack it open and point in suspected ares, Or carb cleaner with the straw.

Carb cleaner is a good idea.

D-Man
26th-April-2010, 09:38 AM
A stethoscope works sometimes too.:yes:

And they're CHEAP and don't make a mess!!

3DTim
26th-April-2010, 03:33 PM
Find someone with a smoke machine.

Paul Wright
26th-April-2010, 04:48 PM
Ether is too explosive and flammable to be spraying externally. WD40 works just as good and is a little safer. It will temporarily seal up a leak. A stethoscope is even safer provided you don't get it caught in the fan. I've made one out of some rubber hose and a small funnel. Run it around suspected areas and listen for the whistling sound of a leak.

balljoint
26th-April-2010, 05:40 PM
I got my EZ EFI installed and I believe I have a vacuum leak. I'm hoping it is the throttle body gasket because I reused the the gasket from my Holley. If it is not, what is the best way to find the leak without using ether?

cheap spray bottle with plain water :yes:

Innovative63
26th-April-2010, 05:56 PM
Ether is too explosive and flammable to be spraying externally. WD40 works just as good and is a little safer. It will temporarily seal up a leak. A stethoscope is even safer provided you don't get it caught in the fan. I've made one out of some rubber hose and a small funnel. Run it around suspected areas and listen for the whistling sound of a leak.

Back in the late 90's I processed MSDSs for Chrysler. At that time, WD-40 was mostly heptane (C7) and the propellants were butane/propane. This is from memory, but I believe it is correct (the big 3 require full disclosure of chemical content on MSDSs).

I see that they have changed their formulations, and the propellant is now CO2.

I have a really old can of WD-40 in the garage, and the warnings are quite different than a recent purchase last year. The older can indicates a higher hazard level than the more recent one. :yes:

Just be sure if you are using WD-40 to check a vacuum leak, you are using a recently purchased spray can. :yes:

Paul Wright
26th-April-2010, 10:30 PM
actually, I like the water spray idea. It should momentarily seal the leak and evaporate easily. Just keep it away from high tension wires and the coil.

chevyIIguy
27th-April-2010, 07:47 AM
if you can find a smoke machine to borrow that would be the best way its safe easy and you can see the not just "hear" it

tnblkc230wz
28th-April-2010, 04:57 PM
Looks like three good ideas that won't turn my car into a BBQ. I've got the spacer and new carb gaskets comming today. If that doesn't work, I'll get the water and funnel trick. I've got some WD 40 also, the newer cans.

Seattle_Mike
28th-April-2010, 10:23 PM
I've also turned my compressor output down to 5-7 lbs and pumped some air into the engine and listened & felt for leaks. They become fairly obvious usually. This works on engines that are typically sealed up good and run a vacuum pump.

mikeorwan
29th-April-2010, 07:31 AM
Around here WD40 is also readily available in a trigger spray bottle.
I buy it by the gallon and refill the sprayer. Very cheap that way.