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Smoke machine to locate vacuum leaks?

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Well, at the time BuickGN was the only GN vendor selling it and to be honest, I would spend the extra $12 with him even though they are the same.
 
I hear ya' Doc. I only posted that as I happened to run across it while I was looking for some silicone turbo hose... and the picture looked 'stangely' familiar. Not trying to stir the pot. I know Mark is a great vendor.... I am however wondering which came first, the chicken or the egg (drop soup)? Those pics are identical. Anyway, while I'm here, I have another question.. :)

I, being the moron I am, still can't figure out how, when using that contraption, how the entire intake side... manifold, vac lines, etc., would be pressurized without a large volume of air escaping thru the engine and out the exhaust via one of the cylinders in an overlap state (both valves open to some degree)... such that one couldn't 'hear' a hissing vac. leak thru a leaking vac connection... and furthermore, if only a small qty. of air squeezes by the closed throttle plate, how could that air be of sufficient qty. so as to pressurize the intake whilst the large volume is leaking out the exhaust?? Clear as mud?? Would it maybe be more likely to work by: 1) pressurize the maf/turbo inlet side w/the tester (throttle closed) to check for leaks at the turbo/IC/TB connections, and then, 2) pressurize the vac lines individually at the block?? and listen for hisses/spritz with soapy water?? I'm thinking outloud.... penny for your thoughts?
 
from the same site....
i like the all stainless THICK flange VBANDs 3" for $40 each!
3.5" and 4" AND 4.5" cool site!

if anyone can find a better price i know i am loved :biggrin:

DS
 
87NAT said:
First thing to do is remove your vacuum block and seal up the TB. Your BLMs should go to 119-120. Then put the vacuum block back on and just plug all the ports on it. See what the blms do again. (Keep resetting ECM as you check each thing.) If vacuum block checks out get a handheld vac pump from a parts store and start checking all 5 of your vacuum lines coming off the vacuum block one at a time. Each one should hold vacuum.

If all 5 lines check out its intake leak most likely.
Click to expand...

+1 that's what I did. You can also T in a vacuum gauge and pinch off lines at various points. I use an old surgical clamp but needlenose will do. I think another area that may be overlooked is the throttle plate shaft bushings, a little water, powder, smoke, etc, on each side should show a leak. good luck
 
I bit the bullet and took the car to the mechanic. His smoke machine found: (1) missing cap on turbo bell where the factory had it connected to the passenger side valve cover
(2) gasket slipped out of position on new EGR valve
(3) leak from new PCV valve, either from valve or rubber grommet that the valve slides in to

After he fixed (1) and (2), BLM dropped to 145 (from 160). The smoke did not find leak #3. He sprayed something on the PCV while we watched the numbers on the scan tool drop to 128. So when I got home, I replaced the PCV valve again but BLM stayed at 145. I used an AC-Delco PCV valve. I ordered a new grommet from the dealer ($8:eek: ) and it will be here later today. Hopefully this will fix the problem for good. Also, I have another problem- 5 degrees of knock at 10 psi boost. I hooked up a mechanical fuel pressure gauge and the fuel pump is good- fuel pressure increased with boost. Would the vacuum leak be causing the knock issue?
 
You can get those grommets at Poop Boys in the "Help" section for a couple bucks. What's the fuel pressure at 10lbs of boost?
 
The missing cap on the turbo inlet bell is a big no no.. that would have screwed up your MAF readings.. hence the high bl's.

Next is adjust fuel pressure and reset the chip.
 
I have a 237 regulator. Non adjustable. I checked it recently and it was around 40 psi so I think it is ok. I know O"Reilly's sells those grommets but I wanted to make sure I have the right one on hand when I remove the old one. Not sure if the old one will come out in one piece. I'm sure I paid more than the grommet is worth but now if I ever sell the car I can say it has a GM grommet ;) I'll take the grommet to the parts store and match it up with the $2 variety so I'll have a few spares.
 
Pronto said:
You can get those grommets at Poop Boys in the "Help" section for a couple bucks. What's the fuel pressure at 10lbs of boost?
Click to expand...

Fuel pressure was about 50. It was hard to see the gauge. I tried taping it to the windshield but it was "clocked" kind of crooked. Fuel pressure definitely went up as I gave it gas, unlike a couple of other pumps I had which caused fuel pressure to decrease with more boost :eek: Those pumps are in the garbage now.
 
Just use your God given ears. Get a long 3/4" OD hose and listen all over the place. At the base of each injector is most important. Listen along the base of the intake manifold, the vacuum block, the TB flange, upper lid...if there are any leaks, you WILL find them with this...unless you're deaf. Even tiny leaks are as loud as a tornado. If you have that steel shim stock intake gasket, dont even both with the test. Just pull that POS out and replace with a good Fel Pro 1 piece pan style gasket.
 
GNRick said:
I have a 237 regulator. Non adjustable. I checked it recently and it was around 40 psi so I think it is ok. I know O"Reilly's sells those grommets but I wanted to make sure I have the right one on hand when I remove the old one. Not sure if the old one will come out in one piece. I'm sure I paid more than the grommet is worth but now if I ever sell the car I can say it has a GM grommet ;) I'll take the grommet to the parts store and match it up with the $2 variety so I'll have a few spares.
Click to expand...

237 reg is suppossed to be 45 line off. If its 40 then pressure is too low and your BL's will go up.
 
It could have been 45, just don't remember for sure. I'll check it and let you know. As for the stock intake gasket, my low mile GN still has it (as far as I know) and blm's are right on the money. Only has 25,000 miles though. My mechanic also recommended the stethoscope/hose test. So I'll get this thing figured out sooner or later. Picked up the PVC grommet today.
 
Replaced the PCV (AC/Delco), and grommet and hose. BLM starts out at 128, then stayed at 135 for 5-10 minutes. Went for a drive, came back and blm was 140. Tried listening for leak with vacuum hose and couldn't find any. So I may be on right track. Forgot to check the valley pan gasket for leaks, but will so. Any other ideas?
 
Did you check the fuel line pressure like Razor suggested?
 
Pronto said:
Did you check the fuel line pressure like Razor suggested?
Click to expand...

Fuel pressure is 45-47 line off. Integrator is 123-133. I sprayed WD-40 all over, including around the intake manifold, throttle body, IAC valve, doghouse. BLM seems to like 141.
 
VadersV6 said:
Just use your God given ears. Get a long 3/4" OD hose and listen all over the place. At the base of each injector is most important. Listen along the base of the intake manifold, the vacuum block, the TB flange, upper lid...if there are any leaks, you WILL find them with this...unless you're deaf. Even tiny leaks are as loud as a tornado. If you have that steel shim stock intake gasket, dont even both with the test. Just pull that POS out and replace with a good Fel Pro 1 piece pan style gasket.
Click to expand...

I tried listening with the hose. No luck. Also sprayed WD-40 around the injectors, no luck. I should mention that I also have an LT-1 MAF and translator, if that matters.
 
87NAT said:
First thing to do is remove your vacuum block and seal up the TB. Your BLMs should go to 119-120. Then put the vacuum block back on and just plug all the ports on it. See what the blms do again. (Keep resetting ECM as you check each thing.) If vacuum block checks out get a handheld vac pump from a parts store and start checking all 5 of your vacuum lines coming off the vacuum block one at a time. Each one should hold vacuum.

If all 5 lines check out its intake leak most likely.
Click to expand...

I'd try this next.
 
Update.....took car back to mechanic. He located a leak at injector #4 (middle of passenger side). So I replaced the O rings on all injectors, blm came down to 139. Then I removed vacuum line at FP regulator and plugged it with my finger. BLM came down to 131. So looks like the FP regulator is bad. I hope so because I just ordered Kirban's off his website. Thanks for everyone's help so far. Should I keep looking or is 131 ok? Can I still get it down to 128?
 
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