LLY: pressure limit for stock FPRV?

[thunder550]

What pressure does the stock LLY FPRV release at?

 

[mike diesel]

I can't say exactly but before I shimmed mine, 100 horse tune would pop mine every time. I'm sure my spring was weak to begin with. I shimmed it and have since never once popped it even with dual cp3's and holding 26100 psi.

 

[LBZ]

I think the lly lets go at 26 000 psi.

 

[S Phinney]

You can get maybe 24000 if you are lucky. It is one that you have to shim for sure.

 

[thunder550]

Ok. I'm chasing a surging issue with the truck, whenever the power cuts out the fuel pressure spikes to almost 26k, and occasionally drops to 10k after. My theory was that the FPRV was opening sometimes when the pressure spikes. Sounds like that's a plausible explanation.

 

[mike diesel]

Usually when the FPRV pops it limits the truck to 2000rpm.

 

[02greysixer]

Usually when the FPRV pops it limits the truck to 2000rpm.

The code can be set to "not reported" and engine protect mode changed to no default with the tuning. Then you'll never know.

 

[Harbin_22]

Bottle test it.

 

[LBZ]

X2. Do a bottle test.
Or just shim it as you should anyways and see what happens.

 

[thunder550]

Shim would probably be good. Does the LBZ FPRV fit the LLY? It's going to be a little bit before I can do this, I think I lost the HGs again yesterday doing some testing. Can't wait to do that job again. :nana3: