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03-19-2007, 06:05 PM | #1 |
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vacuum leak?
ok, so I put in a crate 350 last october with an Edelbrock intake/carb and the only way I can get it to idle well is if I richen it up, otherwise it idles like crap. Its like the more rich it is , the smother and lower the idle can go , but if I try to lean it up, it has to idle at like 1k just to stop shaking. any ideas?
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03-19-2007, 08:17 PM | #2 |
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Re: vacuum leak?
What is your vacuum gauge doing? Have you checked the plug in the bottom back and the manifold port for loose connections. Have you had any backfires lately that might have knocked off a hose somewhere.
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03-19-2007, 08:22 PM | #3 |
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Re: vacuum leak?
also check the timming to, and spray some carb cleaner around the base of the carb and if the idle changes you have a leak there if not keep checking around, pcv if you have it, power brake booster also and just a thought but make sure youre not leaning it out to much
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-steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME |
03-19-2007, 09:34 PM | #4 | |
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Re: vacuum leak?
Quote:
kaboom car on fire !!!!!
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is it fast ? it has a lighting bolt donut? B___H please, I can remove 90% of your so called "beauty" with a kleenex |
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03-19-2007, 08:25 PM | #5 |
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Re: vacuum leak?
well, i dont have a vacuum guage and i think all the hoses are secure but i can double check. I noticed that the intake gaskets looked a little greasy and was thinking that it was an indicator that the leak might be there.
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69 shorty w/ 67 front clip |
03-19-2007, 08:54 PM | #6 |
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Re: vacuum leak?
I'm no expert but how many miles do you have on this motor? Also is it a mechanical choke or a electric?
I assume you have a aftermarket cam? I'm wondering about the cam when you mentioned the shaking.
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03-19-2007, 10:03 PM | #7 |
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Re: vacuum leak?
yea Ive heard of people using carb cleaner but I've always been kinda leary about using it because of the afore mentioned "ka-boom". BTW this is a brand new GM crate 350/ 260hp, its got the stock cam. ALSO how would I use propane? The only kind I have is hooked up to my grill.
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69 shorty w/ 67 front clip |
03-19-2007, 11:23 PM | #8 | |
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Re: vacuum leak?
Quote:
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is it fast ? it has a lighting bolt donut? B___H please, I can remove 90% of your so called "beauty" with a kleenex |
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03-19-2007, 11:06 PM | #9 |
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Re: vacuum leak?
was the carb recommended for the motor? Sometimes guys get to many cfm's and have to run rich......600 cfm is plenty for a 260hp motor.
Do not go thru life without a vacumn gage....go pick one up at parts store, itll save you years of wrenching time. |
03-20-2007, 01:04 AM | #10 |
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Re: vacuum leak?
thanx for the help everyone. I was just out listening to the engine and I can hear it hiss, and when I have the hood up I can hear the hissing sound gradually fade away when I turn off the engine, is that normal?. It sounds like its coming from the drivers side but all I could see is the booster hose and I'm pretty sure it's not leaking.
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03-20-2007, 06:24 PM | #11 | |
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Re: vacuum leak?
Quote:
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03-20-2007, 01:16 AM | #12 |
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Re: vacuum leak?
Short69, its real common to have a leak in that little plastic elbow that plugs into the booster, or in the grommet around it. Seen it many times.
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03-20-2007, 06:38 PM | #13 |
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Re: vacuum leak?
Carfull with the plastic connector it is a check valve that is suposed to keep vacuum in the booster after the engine stops. When it is finished hissing push the brake pedal and if it is that the brake pedal will travel before you feel pressure. But it looks like you found your problem just narrow it down to the booster, check valve, rubber line or the carb connection. but it really is heading to checkvalve or booster or the grommet that goes into the booster.
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72 longhorn c30 502BB/th400/fact air/4.11rear/ custom camper 72 bug(the better half's) under reconstruction 2009 HHR aqua blue 71 GMC k20 350/sm465 2009 Chevy hd3500 6.6 Victory Red crew cab dually Dave & Jeanne |
03-20-2007, 08:51 PM | #14 |
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Re: vacuum leak?
Take the hose off the booster and plug it---that will tell right away if there is a vacuum leak there. Your engine should now run smooth--you can do the same process with each vac line till you find the leak.
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03-20-2007, 10:41 PM | #15 |
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Re: vacuum leak?
Did you use RTV on your intake gaskets around the ports? If you did-rut-o. RTV and gas don't mix.
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