vacuum leak?
August 17th, 2012, 3:45 PM
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vacuum leak?
using a combustion tester to test for a head/gasket failure, but for some reason the vacuum on the engine is weak, it will not suck hard enough. do not have a smoke detector so cannot find leak that way.
what hose would be best to blow smoke into? hopefully not brake booster
98 5.7L vortec
guess i could use a sack with a hole cut out and tied to intake tube
phewww, talk about out of breath
what hose would be best to blow smoke into? hopefully not brake booster
98 5.7L vortec
guess i could use a sack with a hole cut out and tied to intake tube
phewww, talk about out of breath
Last edited by chevyguy1523; August 17th, 2012 at 4:06 PM.
August 17th, 2012, 8:56 PM
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get a few spray cans of carb and coke cleaner. when the engine is running spray every gasket and line, and when the motor starts to bog, you have found your vacuum leak the 5.7 vortecs are notorious for intake/throttle body leaks... let us know what you find
August 17th, 2012, 9:39 PM
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i used a whole can of carb cleaner. found nothing.. also the haynes manual says the egr valve must be tested by a professional. i wonder what them guys use to test them. i thought it was a multimeter, but that is for something else.....
it was trying to stall all during the winter at idle, but it would always revv back up.. but all summer it has been ok..
i found a vacuum that was so strong it sucked antifreeze from deep down in the radiator up in the test tube, so i changed test liquid and allowed it to barely suck 1-2 bubbles a sec. waited for 5 minutes guess it has no combustion leaks.. but small amount of antifreeze disappears, also read a bad egr valve could cause antifreeze to go in the exhaust, ....
guess 1st thing to do next is check the codes
it was trying to stall all during the winter at idle, but it would always revv back up.. but all summer it has been ok..
i found a vacuum that was so strong it sucked antifreeze from deep down in the radiator up in the test tube, so i changed test liquid and allowed it to barely suck 1-2 bubbles a sec. waited for 5 minutes guess it has no combustion leaks.. but small amount of antifreeze disappears, also read a bad egr valve could cause antifreeze to go in the exhaust, ....
guess 1st thing to do next is check the codes
Last edited by chevyguy1523; August 17th, 2012 at 9:48 PM.
August 17th, 2012, 10:08 PM
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i used a whole can of carb cleaner. found nothing.. also the haynes manual says the egr valve must be tested by a professional. i wonder what them guys use to test them. i thought it was a multimeter, but that is for something else.....
it was trying to stall all during the winter at idle, but it would always revv back up.. but all summer it has been ok..
i found a vacuum that was so strong it sucked antifreeze from deep down in the radiator up in the test tube, so i changed test liquid and allowed it to barely suck 1-2 bubbles a sec. waited for 5 minutes guess it has no combustion leaks.. but small amount of antifreeze disappears, also read a bad egr valve could cause antifreeze to go in the exhaust, ....
guess 1st thing to do next is check the codes
it was trying to stall all during the winter at idle, but it would always revv back up.. but all summer it has been ok..
i found a vacuum that was so strong it sucked antifreeze from deep down in the radiator up in the test tube, so i changed test liquid and allowed it to barely suck 1-2 bubbles a sec. waited for 5 minutes guess it has no combustion leaks.. but small amount of antifreeze disappears, also read a bad egr valve could cause antifreeze to go in the exhaust, ....
guess 1st thing to do next is check the codes
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August 22nd, 2012, 8:17 AM
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Matco Leak down Tester - http://www.matcotools.com/catalog/pr...EAKAGE-TESTER/
i have this one and i am very happy with it - http://www.matcotools.com/catalog/pr...GE-TESTER-KIT/
Last edited by GM_tech92; August 22nd, 2012 at 8:31 AM. Reason: added link to leak down tester
August 25th, 2012, 11:07 PM
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have not performed a leak down test,
however, the check engine light showed
p1345
p0161
p1345 {do not know why it read twice}
maybe since the intake gasket and distributor gear was recently replaced, the cam is advanced or retarded
should i use a scanner to see the readings, and while the idle is above 1,000 try to move the distributor gear until the correct reading shows up?
also which oxygen sensor is p0161?
i know this post has nothing to do with a vacuum leak, unless that is the reason for p0161?
however, the check engine light showed
p1345
p0161
p1345 {do not know why it read twice}
maybe since the intake gasket and distributor gear was recently replaced, the cam is advanced or retarded
should i use a scanner to see the readings, and while the idle is above 1,000 try to move the distributor gear until the correct reading shows up?
also which oxygen sensor is p0161?
i know this post has nothing to do with a vacuum leak, unless that is the reason for p0161?
Last edited by chevyguy1523; August 25th, 2012 at 11:11 PM.
August 27th, 2012, 5:57 PM
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have not performed a leak down test,
however, the check engine light showed
p1345
p0161
p1345 {do not know why it read twice}
maybe since the intake gasket and distributor gear was recently replaced, the cam is advanced or retarded
should i use a scanner to see the readings, and while the idle is above 1,000 try to move the distributor gear until the correct reading shows up?
also which oxygen sensor is p0161?
i know this post has nothing to do with a vacuum leak, unless that is the reason for p0161?
however, the check engine light showed
p1345
p0161
p1345 {do not know why it read twice}
maybe since the intake gasket and distributor gear was recently replaced, the cam is advanced or retarded
should i use a scanner to see the readings, and while the idle is above 1,000 try to move the distributor gear until the correct reading shows up?
also which oxygen sensor is p0161?
i know this post has nothing to do with a vacuum leak, unless that is the reason for p0161?
Check the following items:
• A loose CMP sensor causing a variance in the sensor signal
• Excessive free play in the timing chain and gear assembly
• Incorrectly installed distributor - 1 tooth off in either advance or retard positions
• A loose distributor rotor on the distributor shaft
• A loose or missing distributor hold down bolt
i have also seen burred gears on the cam and distributor cause this... if you have this code and any of the following are to blame, you will see a fluctuation at idle... up too twice of desired idle speed... after re-reading your previous posts.. is your cat clogged? a clogged cat causes a serious drop in engine vacuum... so does jumped timing.. any time the car is running poorly you will lose vacuum.. what happens if you open the throttle up while its idling? does it stumble and eventually rev? does it pop and backfire through the throttle body? is it trying to die at idle? how did you perform a compression test? was it with a gauge? what was your reading?
Last edited by GM_tech92; August 27th, 2012 at 6:12 PM.