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

wtf is going on?

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Old Nov 12, 2010 | 02:31 PM
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Default wtf is going on?

I have a lt1 from a 95 z28 and we swapped a walbro 255 pump in it and it was all fine til about a week ago. The buzzing sound it makes with the key ''on'' would buzz than stop like usual, than when i fire it up it buzzes all the time. And i know they are supposed to be running all the time but it has never buzzed this loud. I have super 44s no cats on the truck so its pretty loud andi hear it as much as hte exhaust. Well we put a gauge on it and it read, 20psi key on, 38psi idle and reving it would go up to 50+psi than drop to 30psi to than even out at idle again at 38psi. Well we replaced the FPR with a OEM replacement and it read 42 psi at the key ''on'', 39psi at idle and when we rev'd it it never dropped below 39psi coming back down on rpms.


Well test drive it seemed fine, pulled hard and all. Well just now i drive it and it feels like my 300 hp is now 100 hp. It feels like it hits a wall. This is what it was doing before we swapped the fuel pressure regulator in it for a OEM. And now its doing it again. I dunno what it could be. THe fuel filter isnt a year old, and we swap a new one in every year and i dont put more than 10k on the truck a year so its not alot of miles.

Someone help me out!
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Old Nov 12, 2010 | 06:18 PM
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When did you install the Walbro? Who did you get it from?

This sounds like it could have been one of the foreign knockoffs that fail pretty much immediately.
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Old Nov 12, 2010 | 10:23 PM
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Originally Posted by qc97z
When did you install the Walbro? Who did you get it from?

This sounds like it could have been one of the foreign knockoffs that fail pretty much immediately.
January of this year I got it installed and it was from Auto Performance Engineering. Or APEusa.com. Its pissing me off bc i was going to take it to the track and i spend 100 bux on a part that didnt fix the issue
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Old Nov 14, 2010 | 07:44 PM
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bump?

Well we put a gauge on it and it read, 20psi key on, 38psi idle and reving it would go up to 50+psi than drop to 30psi to than even out at idle again at 38psi. Well we replaced the FPR with a OEM replacement and it read 42 psi at the key ''on'', 39psi at idle and when we rev'd it it never dropped below 39psi coming back down on rpms.


Well test drive it seemed fine, pulled hard and all. Well just now i drive it and it feels like my 300 hp is now 100 hp. It feels like it hits a wall. This is what it was doing before we swapped the fuel pressure regulator in it for a OEM. And now its doing it again. I dunno what it could be. THe fuel filter isnt a year old, and we swap a new one in every year and i dont put more than 10k on the truck a year so its not alot of miles.

somebody help me out! I am going to try some fuel injector cleaner and see what that does hopefully its just a clogged injector.
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Old Nov 14, 2010 | 08:01 PM
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Originally Posted by qc97z
When did you install the Walbro? Who did you get it from?

This sounds like it could have been one of the foreign knockoffs that fail pretty much immediately.
are you talking about those walbro pumps they sell on ebay for like $100?
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Old Nov 14, 2010 | 08:10 PM
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Originally Posted by rg501
are you talking about those walbro pumps they sell on ebay for like $100?
are the walbros stamped with the name on the pump at all? The place i got it from didnt have a photo of the product so if they dont than this is alittle concerning to me.

actually i see alittle engraving on the picture in the link, but this is what i got as my kit

http://apeusa.com/html/lt1_kit.html

woudl i be producing too much power for this pump to handle?
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Old Nov 15, 2010 | 08:50 AM
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That pump should easily support your power. Your new fuel pressure doesn't seem to be a problem, but if you still suspect fueling to be an issue, tape that fuel pressure gauge to the hood and go for a WOT romp.
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Old Nov 15, 2010 | 09:41 AM
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Do you know if the fuel pump bucket was reused? Reason I'm asking is if it is not reused the pump is not submerged in fuel at all times and will run hotter than it should. Enough dramatic heat cycles and the pump may have a premature death.
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Old Nov 15, 2010 | 03:49 PM
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Originally Posted by RamAir95TA
That pump should easily support your power. Your new fuel pressure doesn't seem to be a problem, but if you still suspect fueling to be an issue, tape that fuel pressure gauge to the hood and go for a WOT romp.
yea i was hoping that the pump would handle the power i have. And thats what we are going to do on friday, probably take the hood off and WOT it with a gauge on it. It didnt feel this bad when I had a stock pump in it and it felt like it was holding back, but to me it seems like its gotta be the pump.
Originally Posted by SS RRR
Do you know if the fuel pump bucket was reused? Reason I'm asking is if it is not reused the pump is not submerged in fuel at all times and will run hotter than it should. Enough dramatic heat cycles and the pump may have a premature death.
honestly I am not sure, the guy that helped do the swap for me did it one day when I was at work so this is one thing I am not sure what he did, lol
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