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SCrazy
11-05-2010, 10:06 AM
I want to spend so time trying to determine if there are any vacuum leaks on the car.

Is it possible to pressurize the entire intake, blower, IC, manifold, exhaust systems. Something like making up an adapter with a shrader valve and install in on the MAF then block of the tail pipes and put 40 or so pounds of air pressure on the entire system.

If anything I would think the header ball flanges would be leaky as hell but everything else should be tight.

Is there any chance something like this could work???

HOW THE HECK DID I PUT THIS IN THIS FORUM>>>>>DANG IT!!!!!!!

fturner
11-05-2010, 11:43 AM
Move post to Technical.......

Fraser

XR7 Dave
11-05-2010, 11:58 AM
The best way to test for a vacuum leak is with a smoke machine. If you do use pressure, I do not recommend exceeding 20psi as you may blow out or damage seals etc.

S_Mazza
11-05-2010, 12:12 PM
I want to spend so time trying to determine if there are any vacuum leaks on the car.

Is it possible to pressurize the entire intake, blower, IC, manifold, exhaust systems. Something like making up an adapter with a shrader valve and install in on the MAF then block of the tail pipes and put 40 or so pounds of air pressure on the entire system.

If anything I would think the header ball flanges would be leaky as hell but everything else should be tight.

Is there any chance something like this could work???

Yes, definitely. I recently tested for and found a vacuum leak on my car with a similar setup. It was pretty easy once I found the right parts and fittings. What I did was to buy a vacuum / pressure hand pump, used for testing HVAC systems. Then I bought a tapered rubber plug of a size that approximately fit the IC tubes and throttle body. The plug had a small hole in the middle. I bought some 1/4" OD copper tubing. It fit nicely through the hole in the plug and made a good seal. At the other end, I used an adapter to mate it to the pump. So then I pumped while holding the plug in place and looked for the leak.

In my case, I believe I found that it was leaking when I pumped air in at the throttle body. But I still couldn't isolate the spot. So I pulled the blower, plenum, and top IC tube off as a unit. I put the plug in the top port of the intercooler and verified that the intercooler, lower IC tube, return plenum, intake manifold, and valves were all sealing just fine. So I knew the leak had to be in the blower section. With the aid of some vacuum caps for the hard fittings and a buddy to pump while I blocked the IC tube end with my palm, I quickly found that there was a leak at the joint of the blower and inlet plenum.

I will try to get some part numbers for you later, when I am at home. I do have this ... Here is a listing for the pump I bought. (I got a better deal by finding it used on eBay, but this price still isn't bad.) http://www.patriot-supply.com/products/showitem.cfm/46171


HOW THE HECK DID I PUT THIS IN THIS FORUM>>>>>DANG IT!!!!!!!

Booze for breakfast? ;)

slowpoke
11-05-2010, 12:27 PM
brake cleaner works pretty good to.

DrFishbone
11-05-2010, 12:42 PM
I made a cap that clamps onto the TB out of a 3" rubber pipe cap (from Home Depot), a large hose clamp, and an old valve stem. If I want to check for leaks, I air up the air compressor (be mindful of pressure - like Dave said), then have someone let air into the gadget and listen/test for leaks. It's real quick, cheap, and works perfect. :cool:

http://www.homedepot.com/h_d1/N-5yc1vZ1xj7/R-100372304/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

TbirdSCFan
11-05-2010, 02:30 PM
Fastest and easiest way I've found to find to locate a vacuum leak is with a mechanics stethoscope. With the engine running, you can probe the lines and actually hear it. I don't know how well it works for a boost leak, but if I can find a problem 75% of the time that way, I've saved hours of troubleshooting.

XR7 Dave
11-05-2010, 02:32 PM
brake cleaner works pretty good to.

Brake clean doesn't work at all for small leaks because the EEC will compensate faster than you can detect any change in rpm. Many a would-be mechanic has been fooled by this technique. Works for carburetors but not for a modern EFI where the EEC has control of ignition timing.

Guys, smoke machine. It will tell you in 3 minutes every conceivable leak however minuscule. It's worth the money to have a mechanic test the vehicle and as I said, only takes a couple minutes, no rigging of anything required. Call around and find a mechanic willing to do it for you without charging $100.

Pressurizing is ok for some things, but you still have to find the leak. If, lets say the bottom of your supercharger inlet was leaking, how would you find that? Smoke machine will tell you in 3 minutes while you drink your coffee, smoke a cigarette, whatever, no disassembly required.

Ira R.
11-05-2010, 04:47 PM
Brake clean doesn't work at all for small leaks because the EEC will compensate faster than you can detect any change in rpm. Many a would-be mechanic has been fooled by this technique. Works for carburetors but not for a modern EFI where the EEC has control of ignition timing.

Guys, smoke machine. It will tell you in 3 minutes every conceivable leak however minuscule. It's worth the money to have a mechanic test the vehicle and as I said, only takes a couple minutes, no rigging of anything required. Call around and find a mechanic willing to do it for you without charging $100.

Pressurizing is ok for some things, but you still have to find the leak. If, lets say the bottom of your supercharger inlet was leaking, how would you find that? Smoke machine will tell you in 3 minutes while you drink your coffee, smoke a cigarette, whatever, no disassembly required.

Do you mean as simple as if you were checking for exhaust leaks?? What would you hook it up to, the TB?

Ira

BLOWN38
11-05-2010, 05:39 PM
Pump it in the CAI nipple or one of the vacuum lines on the blower inlet.

SCrazy
11-05-2010, 05:48 PM
so if i picked up a leftover 500w holloween smoke machine and make up some ghetto adapter to blow the smoke into the intake pipe somewhere before the MAF the smoke with then work its way throughout the system and leak out of the smallest little leak?? Will the smoke machine pressurize the system? Do I need to block off the exhaust?

Does anybody want to buy a lightly used smoke machine?

edit: Wow those little smoke machines put out about 2500cfm, I'm sure the fan won't do alot of static pressure but it should force smoke through all kinds of stuff.

XR7 Dave
11-05-2010, 06:58 PM
It will fill the engine with smoke and will leak out visibly from any and all orifices. Definitely don't want 2500cfm, more like 10 cfm if that. It doesn't push out very much smoke at all. It won't simulate boost, but it will find all vacuum leaks, guaranteed. It doesn't create any pressure in the system.

S_Mazza
11-05-2010, 11:04 PM
Pressurizing is ok for some things, but you still have to find the leak. If, lets say the bottom of your supercharger inlet was leaking, how would you find that? Smoke machine will tell you in 3 minutes while you drink your coffee, smoke a cigarette, whatever, no disassembly required.

Funny, that's exactly where my leak was. I knew there was a vacuum leak because of testing with starting fluid ... but it was not at all obvious where it was. It just wasn't precise enough. And the pressure test doesn't show you exactly the leak is ... since air is invisible and all. So that is why I had to remove some parts to isolate the leak. If I had a smoke machine or a knowledgeable / willing mechanic nearby, I guess that would have been more convenient. But it all worked out.

Dave, you probably know this already, but your PM box was full earlier. To summarize what I was going to PM you, by mail it is.

SCrazy
11-06-2010, 11:49 AM
I went to I-Party this morning and everything Holloween was 1/2 price. I got a fog machine and a gallon of fog juice for $26.

Gonna see how this goes

RotaryKlown
02-03-2011, 02:31 PM
when testing for vacuum leaks with a smoke machine, should the car be running or off? i hate that i have to ask this lol

90turbo1
02-03-2011, 05:02 PM
Brake clean doesn't work at all for small leaks because the EEC will compensate faster than you can detect any change in rpm. Many a would-be mechanic has been fooled by this technique. Works for carburetors but not for a modern EFI where the EEC has control of ignition timing.

Guys, smoke machine. It will tell you in 3 minutes every conceivable leak however minuscule. It's worth the money to have a mechanic test the vehicle and as I said, only takes a couple minutes, no rigging of anything required. Call around and find a mechanic willing to do it for you without charging $100.

Pressurizing is ok for some things, but you still have to find the leak. If, lets say the bottom of your supercharger inlet was leaking, how would you find that? Smoke machine will tell you in 3 minutes while you drink your coffee, smoke a cigarette, whatever, no disassembly required.

PLUS ONE ON THIS, THE SMOKE MACHINE IS INVALUABLE TO THE MODERN MECHANIC. THEY ARE EXPENSIVE BUT PAY THEM SELVES BACK VERY QUICKLY. LIKE SAID I FOUND EVERY LITTLE TINY LEAK KNOWN TO MAN WHEN i DID MY 1992 THE BIGGEST CULPRIT BEING THE DIPSTICK TUBE AND THE BYPASS VALVE LEAKING.

LIKE SAID PAY A SHOP A SMALL FEE AND LET THEM SMOKE TEST IT, IF YOU FIND A GOOD SHOP THEY WILL EVEN LET YOU WATCH THEM

S_Mazza
02-03-2011, 06:16 PM
when testing for vacuum leaks with a smoke machine, should the car be running or off? i hate that i have to ask this lol

It should be off. If it was on, the engine would ingest all or most of the smoke and the test wouldn't work well.

whitecl0ver
02-08-2011, 11:30 AM
So where do you put the smoke in at? Could I just rig up some sort of pipe, take of my air filter and pipe in through the intake??

Then it will start puffing from every place with a leak??

Would this one work? Still a bit high at 1500 cfm, but under $40 lol
http://cgi.ebay.com/CHAUVET-HURRICANE-700-FOG-SMOKE-PRO-MACHINE-H-700-H700-/230511061409?pt=LH_DefaultDomain_0&hash=item35ab87a9a1

SCrazy
02-08-2011, 11:39 AM
So where do you put the smoke in at? Could I just rig up some sort of pipe, take of my air filter and pipe in through the intake??

Then it will start puffing from every place with a leak??

Would this one work? Still a bit high at 1500 cfm, but under $40 lol
http://cgi.ebay.com/CHAUVET-HURRICANE-700-FOG-SMOKE-PRO-MACHINE-H-700-H700-/230511061409?pt=LH_DefaultDomain_0&hash=item35ab87a9a1

You got it

whitecl0ver
02-08-2011, 11:43 AM
You got it

Nice!!

I was checking ebay and for the Smoke Machine "Vacuum Tester Tool" $899.99 LOL

SCrazy
02-08-2011, 12:46 PM
Nice!!

I was checking ebay and for the Smoke Machine "Vacuum Tester Tool" $899.99 LOL

You'll be amazed how much smoke that thing pumps out and where the smoke puffs out of on the car. The adapter I made up to attach it to the car was pretty ghetto but it worked like a charm.

rad_al_
02-08-2011, 01:07 PM
Some good info there! I know I have leaks cuz the car runs terrible.
I checked around at work, found out my friend has one he'll sell me... FI'TEEN DOLLA!!!

RotaryKlown
02-09-2011, 11:31 AM
well i purchased a smoke machine last week, tested the car on sunday. NO LEAK! lol....so i decided to check out my IAC. looked pretty crudded up so i sprayed some brake cleaner in it, then some wd40. car is running fine now lol. on the plus side, while i was poking around, i found out that a previous owner installed red top injectors:D though now i have to buy another sampling tube for the c&l before i install it

S_Mazza
02-09-2011, 12:09 PM
well i purchased a smoke machine last week, tested the car on sunday. NO LEAK! lol....so i decided to check out my IAC. looked pretty crudded up so i sprayed some brake cleaner in it, then some wd40. car is running fine now lol. on the plus side, while i was poking around, i found out that a previous owner installed red top injectors:D though now i have to buy another sampling tube for the c&l before i install it

Red tops are stock for 89-93's! They are 30-lber's. Or do you have a non-stock engine?