The car sometimes runs great and other times I get lots of knock and no power I bought a hood mounted fuel pressure gauge and now I know why. the fuel pressure sometimes will rise 1:1 and other times it does not. The pressure never drops it just doesn't rise so I'm thinking that the accufab regator I have isn't working properly? Is there a way to clean it or to check the regulator to see that it's working properly? Or any other ideas as to why my car does this?
Fp not rising 1:1 under boost
- Thread starter 1quickfrc
- Start date
captflash
Old and Bold
- Joined
- May 10, 2009
I had the same thing happening to me and it ended up being the fuel pump. It could also be a voltage drop at the pump, 1 volt drop is NOT good. Check your voltage at the wiring harness at the pump and if it's less than 12.5 volts start tracing out the harness. Also do you know what fuel pump you have and how old is it. A new walbro pump and hotwire kit is a cheap up grade and well worth the money.These cars don't react well to low fuel pressure. Good luck.
I wouldn't think it would be the pump because it doesn't lose pressure it just doesn't raise sometimes. It works sometimes which leads me to think it's the regulator... But I will check voltage. It's a walbro pump and it's atleast 3 years old I've only driven it about 200 miles in three years though
Firechaser
V8-2 cylinders=2x the $
- Joined
- Jan 23, 2010
I second pump/wiring...sounds like an occasional voltage drop or the pump is just slowly dying...not uncommon on any fuel pump on any car really.
What size injectors do you have and what duty cycle do they top out at? How much base fuel pressure and how much boost?
42lb injectors no idea of the duty cycle base fuel pressure is around 43-44psi and im running 21-22 lbs of boost... i just double checked the base fuel pressure and decided to give the regulator a few light taps with a brass hammer just incase the diaphram, spring or other internal parts may have sat with bad gas or whatever and gotten a little "sticky" from sitting. i took it up the road after words and it ran great i was trying to keep the car pointed in a straight line but fuel pressure was right around 65-70 as far as i can tell. I will give the car a break double check things later on and hope my problem was infact a screwy regulator. I will probably get a new fuel pump and a hot wire kit for the pump as well as i do not know how old the walbro in it now is.
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