whats the best way to search for a vacuum leak
08-27-2007, 12:23 PM
#1
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whats the best way to search for a vacuum leak sometimes when i back the car out of the garage the rpms hang at 2200 rpms for 3 seconds or so, then they come back down to 1100rpms for idle- which i think is way to high to idle at 1100rpms all the time. if had had a vacuum leak, wouldnt the rpms hang every time i backed up? also when i start the car it goes right to 1500 rpms for a few seconds before it settles down to the 1100rpm idle. so whats the best way to search for a vacuum leak?
p.s. i pretty much had it nickel and diming for 5 hp here and 5hp there with the ls1. its time to move on. or i might do nothing. or i might sell the beast for a viper or drop a 454 lsx in the car. any suggestions? what would you do?
p.s. i pretty much had it nickel and diming for 5 hp here and 5hp there with the ls1. its time to move on. or i might do nothing. or i might sell the beast for a viper or drop a 454 lsx in the car. any suggestions? what would you do?
08-27-2007, 02:20 PM
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Originally Posted by AutomagicLS1
Get a can or starter fluid and spray around the base of the intake/the back/throttle body everywhere else the motor will ramp up if there is a leak
08-27-2007, 03:10 PM
#5
Hes talking about diesel cold starting spray. I don't think I would want to spray ether around a running motor. I 've always played it safe and just sprayed some WD40 around the suspected leak and see if it causes any smoke to come out the exaust.
08-27-2007, 04:08 PM
#6
Use a can of carb cleaner.. what happens is that if you spray on the leak.. the carb cleaner will seal the leak for a second two and the engine will richen up for a moment and the RPM will change and then back again. Just spray a bit at each point and wait a second or two and listen or watch a tach. If nothing happens, move to another spot or fittings. check around the base of the Intake, T/B, PCV and any fitting that could cuse a leak.
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08-27-2007, 04:48 PM
#8
Smoke machine or propane. WD40 is highly flameable as are other solvents. Using these methods needs to be done with a high degree of care and if you are the accident prone type have a fire extinguisher handy or don't do it. You might be better off hiring a pro.
08-27-2007, 06:50 PM
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Originally Posted by bczee
Use a can of carb cleaner.. what happens is that if you spray on the leak.. the carb cleaner will seal the leak for a second two and the engine will richen up for a moment and the RPM will change and then back again. Just spray a bit at each point and wait a second or two and listen or watch a tach. If nothing happens, move to another spot or fittings. check around the base of the Intake, T/B, PCV and any fitting that could cuse a leak.
