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long term fuel trim and vacuum ?

Old 09-01-2012, 12:32 PM
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Default long term fuel trim and vacuum ?

Installed ls6 cam and 241 ls1 heads with studs and mls gaskets in prep for turbo kit.

Long story short is now only have 15lbs vacuum at idle and the long term trim on drivers side is +9.38. I cant find vaucuum leak anywhere think i have to pull the head and get the valves checked on the drivers side? The long term trim on the pass side is around zeroish.

Any help would be great.
Old 09-01-2012, 01:04 PM
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Swap the O2 sensors and see if the trim follows. Spray around the intake real good for leaks. Are there any exhaust leaks at all?
Old 09-01-2012, 06:20 PM
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Originally Posted by Gadgetized
Swap the O2 sensors and see if the trim follows. Spray around the intake real good for leaks. Are there any exhaust leaks at all?

Sprayed every possible place 3 different times. Hooked 3 diff. vacuum gauges ect.... Cant find the slightest lest. Swapped O2 sensors and still no change. I think maybe I will tear her back down and redo the Head gaskets....I cant really think of anything else at this point????
Old 09-01-2012, 06:36 PM
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Drag your laptop around to the engine bay while uour spraying. Log/watch the STFT when it changes you have foumd your leak.
Old 09-03-2012, 06:19 AM
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Originally Posted by Bigschwerm
Sprayed every possible place 3 different times. Hooked 3 diff. vacuum gauges ect.... Cant find the slightest lest. Swapped O2 sensors and still no change. I think maybe I will tear her back down and redo the Head gaskets....I cant really think of anything else at this point????
If you still cant find a leak after doing what BlackGMC suggested, swap injectors from bank 1 to bank 2. See if the problem follows. Also check the injector wiring.
Old 09-03-2012, 07:00 PM
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Tryed everything swapped injectors ect..... ended up swapping in a diff. Maf just for ***** and that was the culprit.
Old 09-03-2012, 08:00 PM
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Good to hear.
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