Motor revs to 3500k on startup, HELP!
02-15-2005, 08:00 PM
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Motor revs to 3500k on startup, HELP! Hey gang, I am in the process of rebuilding a 2003 ECSB Silverado with a 5.3 that was in a pretty nasty accident up front. I have it all back together now but when I tried to start it up, it wants to instantly rev to over 3k!? I have checked everywhere for vac leaks but cant find any. The only thing I have done to this is have the PCM sent off to a tuner to get the efans turned on and a few other tweaks that would not effect my gas mileage while I did the body work. Anyone have a clue as to what could cause this? Thanks in advance...
02-17-2005, 02:16 PM
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Well i wouldn't be worried about iac, drilled holes, or linkages...in the 03's they have throttle acutated control which means fly-by-wire setup all idle is controled by pcm and TAC module. First things first, start it while looking in the TB and make sure it is not open and you are not setting any ses lamps for tac module performace reasons. If it is a vac leak big enough to idle at 3500 that it should be easy to find(i.e. brake booster hose)
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02-17-2005, 02:19 PM
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You DEFINIETELY have a vacuum leak. I battled this problem for 2 weeks before I found a hole in my intake.
Please triple check all hoses and such, the hole will have to be of big size. My camaro would rev to 3500, then fall and die. Vacuum leak fixed and my problem went away.
Please triple check all hoses and such, the hole will have to be of big size. My camaro would rev to 3500, then fall and die. Vacuum leak fixed and my problem went away.
02-17-2005, 02:50 PM
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Originally Posted by MrXerox
Hey gang, I am in the process of rebuilding a 2003 ECSB Silverado with a 5.3 that was in a pretty nasty accident up front. I have it all back together now but when I tried to start it up, it wants to instantly rev to over 3k!? I have checked everywhere for vac leaks but cant find any. The only thing I have done to this is have the PCM sent off to a tuner to get the efans turned on and a few other tweaks that would not effect my gas mileage while I did the body work. Anyone have a clue as to what could cause this? Thanks in advance...
the TPS on my truck sliped on the throttle shaft just a little, and it caused the same thing.
because the TPS was out of adjust ment the throttle blade was open a little more than the PCM thought.
hope that helps.
02-17-2005, 02:57 PM
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Originally Posted by CamaroCain
Well i wouldn't be worried about iac, drilled holes, or linkages...in the 03's they have throttle acutated control
