So I shimmed the FPRV on my LB7.
It was a pain in the ass to get to.
Found a good write up on how to do it and went for it.

So now the truck feels totally different.
It has a bit more pep and more responsive throttle.
I’m still getting a P1093 CEL but not as easily I think.
The trucks power is much better than before tho.

Anyone have an idea of why it’s more responsive?
Its more responsive down low.
Talking in town type driving.
Off the line power and rolling power at 30mph.
I’m not even talking about it being better at WOT.

what is the fprv?

fuel pressure regulator valve. have been thinking about doing that to mine. how long did it take you?

Fuel Pressure Regulator Valve

lol we must have posted right at the same time. as soon as i clicked reply i got an email saying you responded. how long did it take you?

Took me about 2 hours

what other mods are done to your truck that you noticed a large differnce with this one?

Washer OD needs to be smaller than .370
Standard M4 washers worked very well.
They are about .03 thick
I read one post where the guy only used 2 washers and another where the guys use 4, I used 3. LOL!

I can PM you a link to the write up I found if you want?

if you don't mind that would be nice. thanks.

It’s the first true mod I have done myself to the truck.
It came with a Hypertech programmer but I put it back to stock because I’m having a P1093 CEL. I bought EFI Live to diagnose the problem and am in the process of either changing the CP3 or injectors in the near future.


EDIT... The truck is stock no exhaust or CAI

Hey joeracer01 have you noticed any change in mpg? Can you post the link for the shimming?

Hey joeracer01 have you noticed any change in mpg? Can you post the link for the shimming?


Have not checked yet.

http://xxx.dieselbombers.com/lb7-bombs-aftermarket/34726-lb7-fprv-shim-mod.html

Change XXX to WWW
Not sure if they get mad here if you post live links to other forums.

This isnt necessary unless you have either updated your CP3 or modded your CP3 so you can produce over 24K psi. I have been playing with the max commanded fuel pressure on my truck and I am yet to pop the FPRV. Its more or less there to protect the fuel system when you go from full load to no load and the is a bit of lag between the amount of fuel being injected and the about of pressure your CP3 is producing. As a result of this you get a spike in the fuel pressure (your engine is no longer injecting fuel, but your pump for that split second is still producing all that pressure) and its this valve that helps reduce the spike.

JMHO

joeracer01 could you pm me the link if you still have it wasnt to do it to my truck.

why you have more power is do to less fuel being sent back to the tank and keeping more fuel in the rail

Even with a higher spring tension your valve could still be leaking by. Not leaking out but leaking by. Just a guess but you do need to perform a bottle test at this point.