Vacuum leaks
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Supreme Member
Joined: Jan 2001
Posts: 1,411
Likes: 3
From: Rock Hill, SC
Car: 1999 Pontiac T/A Firehawk
Engine: ***'s Engine
Transmission: T56
Vacuum leaks
Question #2 for the day.
I've found what appears to be several vacuum leaks (or possible one big one) on my Qjet. Either all of the vacuum hoses in the front leak, or the air horn gasket is leaking.
I used a shop rag to cover the primaries lightly, and the motor sped up and smoothed out. If I pressed down on the towel enough to completely seal the primaries off, the motor sputtered for about 5-6 seconds before stalling.
The car responds to carb cleaner sprayed at the airhorn gasket starting at the air valve and moving all the way around the front of the carb to the beginning of the airhorn on the other side. I'm going to remove and plug all the vacuum lines in the front tonight and try it again (MAP/VAC sensor is in the back and there's no leak there).
If it's the air horn gasket, aside from the airhorn being warped (which it isn't, I checked it with a straightedge), how could I fix that? I thought about using two gaskets, and one person suggested coating the gasket in vaseline. I don't have any other airhorns I can try, since the other two I have are junk because the the TPS adjusting screw is screwed up.
I've found what appears to be several vacuum leaks (or possible one big one) on my Qjet. Either all of the vacuum hoses in the front leak, or the air horn gasket is leaking.
I used a shop rag to cover the primaries lightly, and the motor sped up and smoothed out. If I pressed down on the towel enough to completely seal the primaries off, the motor sputtered for about 5-6 seconds before stalling.
The car responds to carb cleaner sprayed at the airhorn gasket starting at the air valve and moving all the way around the front of the carb to the beginning of the airhorn on the other side. I'm going to remove and plug all the vacuum lines in the front tonight and try it again (MAP/VAC sensor is in the back and there's no leak there).
If it's the air horn gasket, aside from the airhorn being warped (which it isn't, I checked it with a straightedge), how could I fix that? I thought about using two gaskets, and one person suggested coating the gasket in vaseline. I don't have any other airhorns I can try, since the other two I have are junk because the the TPS adjusting screw is screwed up.
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Joined: Feb 2002
Posts: 438
Likes: 5
how about some rtv sealant. Just a recommendation, but I would just replace all your vacuum lines, I just bought 10 ft, and it was only like $4.50 for all of it. I replaced all the vacuum lines, leaking or not. Now they are all new and I don't have to worry about it.
Thread Starter
Supreme Member
Joined: Jan 2001
Posts: 1,411
Likes: 3
From: Rock Hill, SC
Car: 1999 Pontiac T/A Firehawk
Engine: ***'s Engine
Transmission: T56
The vacuum lines ARE all new. They were replaced when I did the engine swap in Dec '99. Some have even been replaced since then.
Doesn't matter, really. I found the vacuum leak. Turns out the large vacuum fitting at the top center of the carb was not pressed in very well. I pushed it in by hand but I don't trust it. I'm considering tapping it in with a hammer, and if that doesn't work, I may seal it with JB weld or something.
Doesn't matter, really. I found the vacuum leak. Turns out the large vacuum fitting at the top center of the carb was not pressed in very well. I pushed it in by hand but I don't trust it. I'm considering tapping it in with a hammer, and if that doesn't work, I may seal it with JB weld or something.
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