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

fuel pump or opti??

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Old Aug 14, 2008 | 07:57 PM
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texastransam96's Avatar
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fuel pump or opti??

ok i was taking a buddy for a ride in my ss when it started to totally stutter badly then it died.. i let it sit for a few seconds then it fired right up. i drove it a little while, and then it died on me again... so the next time i tried to start it i finally got it to start, and when i got onto the higway it started bucking again real badly and this time it backfired like a motha****er... i coasted onto the shoulder where i then let it sit for a few more minutes, and it finally started again and stayed going long enough to make it home..

i have replaced the fpr, icm, coil,iac, and tps on this engine..chasing another gremlin, and now this.. i think my only two choices are the opti or fuel pump.. what yall think??

mike
Old Aug 14, 2008 | 08:32 PM
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ok i just went outside after letting it cool down a bit and tried to start the car .. it started right up .. and i was even able to rev it a bit ... if that helps anyone with my situation ..

would that rule out the fuel pump ??
Old Aug 14, 2008 | 10:01 PM
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What about spark plugs and wires? Fuel filter? It doesn't really sound like the fuel pump... at least that's not how mine went out. Mine stumbled when right when it started, then died, then couldn't even start. My guess would be the opti at this point.
Old Aug 14, 2008 | 10:17 PM
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sorry i have changed plugs and wires, fuel filter, as well as all the sensors mentioned above, including a new wiring harness, and o2 sensors... not to say any of it couldnt have gone bad, but i have been chasing a wondering idle, and some weird moments of it missing while cruising, not to mention the new delco FPR ...

i forgot to mention i replaced all this as well, but having done all this and the idle and driveability not changing, then this happening is what led me to believe it would either be the opti or the fuel pump ..
Old Aug 14, 2008 | 11:31 PM
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My car is having the same issue. Same symptoms as yours. I hot wired the fuel pump and it sounded fine for about 10 or 15 seconds but then got really quitet but I could still hear it. This leads me to beleive its my pump 2 year old walbro 255lph. Well I pulled the pump out and after a couple hours of the car being shut off the pump was still fairly warm. I believe the pump was overheating and not putting out the pressure it should. Mine would run fine when cold but started acting up once the car reached operating temps.
Old Aug 15, 2008 | 11:50 AM
  #6  
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ok i just pulled spark plug #1 on this car, and it is almost pitch black... lots of carbon (not oil) on it, and this is from about 5 days worth of use .... what would that be?

also i pulled plug #3, and plug #4, and they look fairly clean ...

Last edited by texastransam96; Aug 15, 2008 at 11:58 AM.
Old Aug 16, 2008 | 11:45 PM
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So did ya figure out your problem?
Old Aug 17, 2008 | 12:26 AM
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texastransam96's Avatar
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not yet... i know one of the spark plug holes was stripped out and that cylinder was bleeding off compression pretty badly, but so far thats all i have been able to come up with, as i am awaiting my arp headbolts and gaskets to come in to fix that problem before i take it to get it scanned for everything else..

mike
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