LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Engine Wont Rev Help!

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Old May 22, 2003 | 04:15 AM
  #1  
jasonlt1's Avatar
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Engine Wont Rev Help!

OK heres the deal...blew up my first 6speed so i let the car sit about a month before i put another one in it...cranked up car runs fine and shifts fine...but all of a sudden i didnt wanna start and then once it started it just would not rev kinda like i had no timming at all...but heres the odd part about it, it idles perfectly fine...and once you get about say 3/4 to full throttle it snaps in and feels like it will run some good 12.20s but otherwise around half throttle it will barely pull itself outta burgerking parkinglot...i changed the ignition module first cause the car does have really high miles and thats one thing that has never been changed, i know everyone is gonna say its the opti but its fairly new 30K or so on it...it has a code that stays on, but why so crappy at half throttle and then it kicks in hard like you started sprayin it or soemthin...i mean it cant be opti or wires/plugs you would thing it would run bad under high load, and sometimes this bad running will start and then just all of a sudden stop and all the cylinders seem to fire evenly...its odd, also just a lil backfire thru the intake (which tells me timming)...what other sensors could cause this and could it be the PCMFORLESS computer jsut taking a dump in general...? it generally does it when the car first started, sometimes it goes away soemtimes it dosent, but say you go in a store to get ciggaretts and it was runnin fine when you shut it off you get back in and you might have trouble getting it to rev enough to get outta the parking lot...but if like i say you can get it above 2500rpm or so and get into WOT it will run like a rapped ape??? someone help me this car was jsut too fun to drive 3 months ago

throttle possistion sensor reads .54 volts at idle and around 8volts at WOT? dont know what its suposed to be
i dont have any scan tools i jsut measured that voltage cause i thopught it was goin out...

car has new coil/plugs/fuel filter/ignition module fairly new wires...i pulled a couple random plugs and the were a lil reddish but they didnt look bad at all(replaced the 2 i pulled)

anyhelp here?? i was thinkin maybe the fuel pump but it has the stock pump (170Kmiles) and a helper pump cause i used to spray the old motor, it has bout 40psi idle and round 48 at WOT but thats not underload considering i have a mechanic type gauge not the kind you have in the car
Old May 22, 2003 | 02:19 PM
  #2  
jasonlt1's Avatar
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ttt
Old May 22, 2003 | 03:32 PM
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it has a code that stays on, but why so crappy at half throttle and then it kicks in hard like you started sprayin it or soemthin...
Get it scanned, so you know what the code is. The pcm is trying to tell you something-listen to it.

but say you go in a store to get ciggaretts and it was runnin fine when you shut it off you get back in and you might have trouble getting it to rev enough to get outta the parking lot
It's trying to tell you to quit smoking.

throttle possistion sensor reads .54 volts at idle and around 8volts at WOT? dont know what its suposed to be
TPS should be .3v-.9v closed and as much as 5v at WOT. Don't know how you are getting 8v when the pcm only supplies 5v to it.

Your description of the problem makes it sound like the TPS is a good suspect.
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