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LT1-LT4 Modifications
1993-97 Gen II Small Block V8

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Old 07-31-2007, 03:54 PM   #1
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Default how to know when fuel pump is going out?

ive been having a weird problem with my 95 T/A the last few weeks.... sometimes it will start up and immediatly die... then when i restart it, it will be fine, or it'll start up, die, restart and be idling really bad, then ill shut it down, restart it and it'll be fine...

its like a crap shoot, sometimes it doesnt have any issues at all, somtimes it'll do the misfire thing or stall, but then on a restart most of the time its fine.. its like its not getting enough fuel on the startup? could it be a clogged fuel filter? i put a new one in it about 2 years and 16k miles ago but i had the car in storage for 4 months this past spring...

i added some fuel injector cleaner about 50 miles ago and it seemed to help but then today it did it again.... i just filled it up with a full tank so hopefully it was just bad gas, however its done it on different tanks of fuel so i dont think thats the case...

not sure if its related or not but i just had it emissions tested a few weeks ago and it failed.... it had 2.7 NOx and needed 2.5 or less, and the HC's were about 2x what they should have been... i had it tested 2 years ago and the car tested fine, and i havent really done anything to it since then other than an msd cap/rotor.....

the plugs/wires have 16k on them and the cap/rotor has about 10k, when it doesnt do the misfire thing it runs fine, so its not an "all the time" misfire, nore does it die on startup every time... oh and FWIW when i first got it out of storage it took 3-4 cranks to get it to fire for some reason... it had 3/4 tank of gas and plenty of fuel stabilizer in it when i stored it....

im throwing no SES lights of any kind....
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Old 08-01-2007, 01:03 AM   #2
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TTT

I think I have the same problem.
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Old 08-01-2007, 04:06 AM   #3
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test with a fuel pressure gauge
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Old 08-01-2007, 02:32 PM   #4
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Testing with a pressue gauge would be the best thing... I just replaced my fuel pump recently and for the longest time I couldn't even hear the pump prime when I turned the key on, so it was going out for a while. Prior to that, I could definitely hear the pump, and I can hear it once again with the new Walboro pump. If you can't hear it prime, yet the car still runs, it's probably on it's way out.
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Old 08-01-2007, 11:05 PM   #5
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Quote:
Originally Posted by jb442
Testing with a pressue gauge would be the best thing... I just replaced my fuel pump recently and for the longest time I couldn't even hear the pump prime when I turned the key on, so it was going out for a while. Prior to that, I could definitely hear the pump, and I can hear it once again with the new Walboro pump. If you can't hear it prime, yet the car still runs, it's probably on it's way out.

i "think" i hear the fuel pump prime....

what i dont get is sometimes it will fire right up, or other times (like it did 3x in a row tonight) it will start and run for <2 seconds and die.... or it will start up and run like **** and then ill shut it down and restart it and it'll be fine..

once its running fine, its fine, it hasnt ever stalled out or started misfiring after its been running, only on the initial startup... and it seems like if its been sitting for 2-3 days (its not my DD) it fires right up, but if i take it out and drive it and then it sits for 3-4 hrs (like tonight at a car show) it will give me problems... like tonight it started right up and immediatly stalled 3-4 times, and then ran fine.....

FWIW i filled it up yesterday with a full tank of 93 octane (or 92, i dont remember, but it was one or the other, different stations here have differnt octanes for "premium" but regular is always 87 and mid is always 89. go figure, lol) so i dont think its bad gas
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Old 08-03-2007, 02:31 AM   #6
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Can you borrow a FP gauge? ... or buy one? (Can't have enough tools if this is a long-term hobby for you). It'll save you some time if you think it's fuel related.
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Old 08-03-2007, 07:16 AM   #7
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Go to a parts store, spend the 20$, put it on the fuel rail, tape the guage to the window, go for a ride w/ a few WOT blast, if it moves siginifgantly, meaning more then 5 psi then the pump is dying.
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Old 08-03-2007, 07:16 AM
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