Do FP regs go bad?


Lone Wolf
May 24, 2001
I was setting the FP and per my gauge, could not get it below 43 psi. Chip says to set at 38 with line off.

I could get it to climb up but never drop lower.

Do FP regs go bad? It is an accufab reg. I wonder if sitting for months wihout fuel flowing through can cause them to 'stick'. It seems the FP was dropping as when I lowered it and got on the gas I got lots of knock.

I am betting it is the gauge but it has only been used twice.

I don't have another FP gauge so if I can't borrow one I need to take a chance and replace the reg, hopefully not to find out the gauge is bad.

Are the gauges that mount to the fuel rail good? Are they safe?
Like any other manufactured part, they can fail. The Accufab's have been noted as one of the better FP's and are usually very reliable and consistent.

Depending on how old it is, where you bought it, etc. you may want to disassemble it and inspect the diaphram.
It is two years old with approximately 5k miles on it.

Are the FP gauges that mount directly to the fuel rail accurate and more importantly SAFE?
Hey Bill...I've had my Accufab on my car since fall of 2001 and haven't had fuel pressure probs...I would bet it's your gauge...FPR's don't have failures quite often...hook up a gauge to the fuel rail and see what you hood-mount gauge connects to the rail and there's no leaks whatsoever...just use teflon tape around the threads...
Gauges on the rail are fine. Lots of people have them, but get a decent quality one. Some are real junk. I know the ones that Jegs sold were decent. Some of us like a "regular" gauge with braided line so you could tape it to the windshield for verification under boost if required. Plus.... some of us are now having trouble seeing gauges that small :)

BTW - John Spina (Casper's Electronics) had a nice fitting for the rail-end that let you mount a FP gauge and still keep a tap for other things (like using fuel injection cleaner from the rail). There have periodically been other posts on the board of places with good quality fittings.
These ae some that I have found that look OK:

Question - if the FP goes higher than the gauge under boost will that damage the guage? I am just looking to set the FP at idle so I don't know if I need one that goes up to 100.

Or I can just purchase another hand-held one on a hose but to be honest those are a pain in the butt and I would like something that is always there for quick checks.
The FP should go up in direct correlation with the boost, so if you have 42 base and 15lbs boost, you should see 57 FP.
So yes, you need one with some "headroom" but not necessarily 100. However, as you see, 60 could be too low and the next step up may only be 100 in the gauge you like.

Even though mine leaked out, I like the liquid filled ones. That are not a "must", but these engines move a lot and I like the vibration buffering you get.