How much hp can that 255 supply? Does your psi drop instantly or slowly while u run through the gears?

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94 Z28 M6 [R.I.P.] ( stupid stupid snowplow)
97 Corvette. MN6. All the goodies.
00 ZR600EFI Arctic Cat

 

ok i sprayed it last year with a stock 125 shot no prob
then this year i put in a walbro255 gss340
fuel pump hit it again with 125 shot this year and as i got to 3rd gear it fell on its face so i put in a 150 shot and it fell on its face sooner ...more nos and more fuel making the pump work harder make sense .. but it runs fine on motor pressure stays the same ,,no big load, like from a fuel solinoid opening to push fuel through..
i put the stock pump back in and the same thing so no pump prob ..no it must be a powerlose or a short,,,,,,,,,,,,,,,,,,,,,,,,,,,,

 

What is your fuel pressure set @??

raise it by 5-10 psi....you do have an adjustable regulator right??

 

just a thought...have you checked your fuel filter? My car did the same, ran fine through 5th gear w/o N2O, but on the juice pressure fell. I replaced the fuel filter even though I could blow through it easily, and the problem is gone. Now, if I could only get traction.....but that is a different story

 

the rilter is new but i'll try a new one

 

I'm telling you its your fpss!! Mine did same thing, ran fine w/o n2o, fall on its face with it. Bottle press. ok;fuel press.ok;wiring ok; I guess the fpss somehow got out of range(?). Adjusted it down just alittle below what I thought was safe and had no probs. since. If ya feel "ballsy" bypass it and see what happens, might want to run a smaller shot for the test. JMO

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96Z M6, 12 bolt Moser(3.73),NX wet kit(all the goodies),MSD 6AL,tayor spiro-pro,NGK tr-6,Star stage 2 kevlar,pcmforless programing, SLP CAI,!maf,LT4 NM,Flowmaster,Hurst roll control,BFG DR's,Pro 5.0,BMR DS loop...
13.52-103.8 mph
60ft. 1.99
no n2o times yet

 

ok heres what i did
i put the stock a.f.p.r back on and it droped for a second but then came back up and stayed at 36psi insted of a non stop drop all the way to 19 psi

and i dont have a fpss on the car but thanks for the help

final result
bad adjustable fuel pressure regulater

thanks guys for all the help

jeff