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

Fuel pump issue?

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Old 10-07-2007, 06:31 PM
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Default Fuel pump issue?

I think I am expieriencing issues from my fuel pump starting to crap out. I was driving down the road and it just died out for no reason to speak of (didn't want to start back up right away either), gets 200 mi to a tank of gas after a tune up but it may need a computer tune after the OR LTs and Y, and the performance is not where it should be for whats been done to the car! If the fuel pump was going out, then it would get poor performance and maybe mileage due to low fuel pressure and possibly cause intermitten hesitation under full throttle in higher rpms (3800-4500), and die out unexpectedly when crusing down the road at 50, right? What do you all think?
Old 10-07-2007, 07:24 PM
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I replaced my stock fuel pump at around 155k miles. At decent rpms in 5th and 6th the car would stutter out at very light throttle for me. For instance if I wanted to go from 75 to 80 it would fall on its face at very light throttle, where as when I first got the car you would have no issue doing such a thing. It would occasionally miss int he upper rpms at WOT and I had to wonder if I was getting the fuel I needed or cooking the #6 wire again. I have a fuel pressure gauge in the car, after the Walbro/racetronix goodies were put in I noticed even at idle my fuel pressure was up higher and steady, I had a noticeable drop with the stocker when first taking off from a stop and it would wobble a bit at idle.
The racetronix wire is supposed to keep pressure steady at WOT, well the pressure was higher at idle, so I'm assuming my unit was tired.
Old 10-07-2007, 08:30 PM
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Hopefully it's not your Opti..

I have a Walbro 255..haven't had a problem with it..
Old 10-07-2007, 09:26 PM
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I hope its not my opti too! Its got probabaly about 2500mi on the Billet MSD unit. It was the first time it ever just shut down on me. I had the stereo up and my exhaust isn't loud(but maybe not for long) so i didn't hear or see it stall out but I think it just cutout suddenly. I tried turning it over a bunch of times and it didn't even pop or anything. It didn't help that my starter is crapping out on it too (has a spot on it that when cranking it, it suddenly sound more like Im grinding it). I sat there on the side of the raod for a minute or so and it fired up like nothing happen! I don't get it but my feeling is that its fuel related only because if the opti were to go bad suddenly why would it start back up?
Old 10-07-2007, 10:20 PM
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could be the pump, could be the opti. my guess is probably the pump, hell you will prob need one eventually (IMO i felt more secure to swap out to the walbro before mine left me stranded) i am really doubting the opti, usually they would cause a miss more than just cut off. put a gauge on it and try it out all around
Old 10-07-2007, 10:56 PM
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Originally Posted by SLawson86
could be the pump, could be the opti. my guess is probably the pump, hell you will prob need one eventually (IMO i felt more secure to swap out to the walbro before mine left me stranded) i am really doubting the opti, usually they would cause a miss more than just cut off. put a gauge on it and try it out all around
Yeah that will have to be my next step... Its still the original so I would expect it to crap out on me, and I pray that thats what has been my problem with it... and holding my car back topend and making it run high 14s/ low 15s!
Old 10-08-2007, 09:01 PM
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If you have to mess with the fuel pump Ill have to recommend cutting a hole in the trunk to get access to it. I know, I know, cutting holes in cars is forbidden, but in this case I think anyone else that has gone through the trouble of dropping the rear end, taking the shocks loose disconnecting the whole tank, and swearing alot will agree. To be honest, the time it took to make the hole and make it look good was the same time it took to go through all the Bull__it of doing it the right way, BUT, anytime I need to get to my fuel pump, I can do so in under a minute. Already came in handy two times.

Last edited by REBORN Z28; 10-08-2007 at 09:02 PM. Reason: wrong wording.
Old 10-08-2007, 09:05 PM
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By the way, B4CZR2, If that was YOU taking the pic of your car doing over 150 while driving, you got some *****.
Old 10-11-2007, 10:38 AM
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Originally Posted by REBORN Z28
By the way, B4CZR2, If that was YOU taking the pic of your car doing over 150 while driving, you got some *****.
Haha! Yeah that was fun!
Originally Posted by REBORN Z28
If you have to mess with the fuel pump Ill have to recommend cutting a hole in the trunk to get access to it. I know, I know, cutting holes in cars is forbidden, but in this case I think anyone else that has gone through the trouble of dropping the rear end, taking the shocks loose disconnecting the whole tank, and swearing alot will agree. To be honest, the time it took to make the hole and make it look good was the same time it took to go through all the Bull__it of doing it the right way, BUT, anytime I need to get to my fuel pump, I can do so in under a minute. Already came in handy two times.
I kinda already planned on making a nice trap door to the fuel pump but yeah I know what you mean about cutting holes in the car. I just swapped in a new fuel tank for my grandfathers 1997 Grand Marquis and I know that was a shitty job. But I need to replace more torque converter and I was thinking of swapping the extra rear I have and go back to 3.23s... yeah I know what people are thinking going smaller is the wrong way! Yeah Yeah, I don't think the 3.42s are doing anything except buring up more gas! My 96 B4C had everything stock including the 3.23s and ran 2.0s 60ft times all day long.

Anyways here is the update:
I narrowed the issue I had with the monetery stumble at 3800-4000rpm down, it was happening at WOT in 3rd gear. I changed out the computer to a PCM4less that has a tune for pretty much the same set up with the LTs ORY Blocked off EGR and AIR pump removal. Car seems to run better, doesn't smell like its running rich. Not any smoke out the back under WOT to mention... drove it about 40 miles total and when I pulled into a parking space later that night when I got home, it stalled out on me again! I didn't really try to fire it back up but did turn it over a few seconds and it didn't fire. So I just went inside and went to bed since it was 1AM. Now I haven't been able to check fuel pressures yet, but does this sound more like the fuel pump? I am going to be replacing it as soon a I get a 100 bucks to throw at it since they are on sale the NewEra (local speed shop) and will need one eventually anyhow...
Old 10-11-2007, 09:25 PM
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sounds like it to me, i dont want to steer in the wrong direction. put a gauge and drive it until it acts up. good luck with it
Old 10-12-2007, 06:34 AM
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Originally Posted by SLawson86
sounds like it to me, i dont want to steer in the wrong direction. put a gauge and drive it until it acts up. good luck with it
Yes, get a FP guage, put in on the windshield and tape it, do some WOT runs and if it drops more then 2 psi then the pump is ****. Racetronix make a great unit, a fairly easy install, I cut the trunk lol.



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