I just took my car to the track today and for some reason my car would fall flat on its face when I floor it in first gear around the 6250 rpm shift point I have set on the shift light. Then I would shift it into 2nd and as far as I can tell it runs great.

At first I thought that it was a fuel issue. I was spraying 2nd and third gear progressively so I thought that maybe the added fuel from the nitrous was making up for it and it was going lean at the top of first gear. So I thought I will spray first to see if it still happens with the shot of wet nitrous, but it still did it.

My revlimiter is set at 7000 in the computer and ignition so its not hitting the rev limiter, it more like the engine just drops out for a second then I shift into second. I also ran a scanner while racing and came up with no codes.

I am running the stock 24lbs LT1 injectors at ~50psi with a 255lph fuel pump, so I tryed adjusting the pressure up for the hell of it but now the regulators seems messed up.

What do you guys think is it fuel related? Should I go with a new fuel regulator and bigger injectors?

Thanks

 

hmmm sounds familiar. get a good fuel pressure gauge on it. go for a drive and flat foot it, see if your pressure drops.

it should stay the same or go up no drop at all if you see pressure drop the pump can't keep up with the fuel needed and should be replaced with a quality 255lph pump no smaller.

could be a coincidence but i just put lt1 injectors on also.

stock pump can't keep up the flow, walbro pump comin will be here tuesday.

 

24lb injectors on a 383? I say do the fuel pump and 30lbs injectors and you'll be fine

 

i agree he can go with bigger injectors.

on a side note drperformance what pump do you have and did you remove the pulsator from in the gas tank when you replaced the pump? if not drop tank and do so that will mess with the afpr.

the added flow of the fuel from the bigger pump messes with pulsator and causes pressure issues.

do a search on walbro install, you will find the info. only reason i know is the research i did when ordering mine. good luck

 

What is the pulsator? And I am running a 255lph fuel pump but I might of messed up I bought one from grannelly motor sports and I am unsure if it is a walbro, but it has bin in the car for three years.

I agree my injectors are small, I have a 12.8:1 compression 383 LT1. but I ran this motor last year, very same set up but I did not spray the nitrous and it ran ok. I remember a little break up off the line at part throttle but that cleared up when I floored it. The only thing I changed on the motor is the coil, I went with a promaster Malory coil to match my Hyfire ignition.

I got no code on a scanner and I think it is a fuel issue, should I go with bigger injectors, a new fuel pressure regulator, and see what happens?

I have a gauge mounted on my fuel pressure regulator and it ran at ~50 psi, but when I went to adjust it higher at the track yesterday it would not go any higher and the internals (spring) seemed to bind up and it no longer feels like it wants to adjust. The second I would shut the car off the pressure would drop to 0 but its always done this, should the pump hold pressure, and slowely bleed off?

 

the fuel pressure regulator should hold that pressure for several minutes, sounds like it has ruptured.

 

The regulator should hold the pressure, or the pump? Since day one with the pump and regulator the pressure dropped to 0 the second the car is shut off.

 

regulator

 

https://www.thirdgen.org/forums/tpi/...light=pulsator


that is a ctually not a good link just search the word (pulsator) you will see

 

I am not sure because I replaced my pump three years ago, but it did come with a length of fuel line shaped almost like an "s" and two hose clamps, was this to replace the pulsator?

 

yeah thats the hose.

some cars didn't have the pulsator some did.
but it can go bad and cause lack of pressure and quick bleed off.

 

Ok I do not think that it is the fuel pump. But I know that I have been pushing my 24# stock LT1 injectors with my 383 12.8:1 compression LT1, so I just bought a set of Ford racing cobalt or blue top 36#. My aeromotive afpr is also jacked up from when I tried to adjust it last Saturday at the track, now the internal spring seems bound up and does not want to adjust properly. So I am also sending that in for repair. Aeromotive also told me that their pressure regulators are not designed to hold fuel pressure for 20 minutes after shut down like stock ones and immediate fuel bleed off at shut down is expected with their unit. And the last thing I will also get an other tune for the new injectors.

I hope this fixes my problem