trust

Can you have to much pressure out of the lift pump? I installed the FASS DDR and new spring and have pretty high fuel pressure, greater than 15 pis on the mechanical gauge way more

To much?

lovinCTD59

I have been running 23-24 psi at the vp44 inlet for years with no issues. I wouldn't go much over 25psi. A buddy with a Fass replacement pump and big line kit runs about 21psi at idle and 13psi at wot with rv275s and edge ez.. personally is get a gauge that reads up to 25psi. I have an Isspro mechanical gauge..

j-fox

You need to talk with people who rebuild them.

I would be skeptical of an answer from the web, even this one.

Many have argued high and low pressures are both ok.
There is a designed pressure.

high bid

The higher the psi the greater strain on the fuel filter canister, thus possible leakes at the canister o-rings. I exp this when running 25psi. IMO, 15 psi @ wot is plenty as the IP relief valve opens at 14psi.

rickf

I see you got your new spring, That is the same pressure I am running and have no problems whatsoever. As far as talking to the manufacturers..............These are the same people that said there were no problems at all with the VP-44!

Rick

trust

Thanks guys, i appreciate the perspective... Yes Rick I did get the new spring and am putting it in tomorrow, the current set up (expanding the original spring coil spacing) was what Geno's suggested as an immediate 'cure' and that sure did boost the pressure!

i am replacing the mechanical gauge under the hood with something greater than 15# max which is what I had in there and was fine before but is now maxed out... The incab gauge is also maxed out

I'll see what the new spring and new gauge tell me

Again, thanks for the insights!

taken5875

I have also been running between 21-24psi since 03 and over 120k miles. I have been told that running too high of a psi can cause some diaphragm to fail. But I am a carpenter so take it for what it's worth.

KATOOM

The pressures you mentioned are not harmful to the VP. But to make something perfectly clear, there is ZERO proof anywhere whereby anyone can definitively show that high fuel pressure harms the VP. And in saying that, "high" to some people is anything over 20 psi, but there are a few guys who've even consistently ran their fuel pressure up around 40 with no issues. As previously mentioned, you can take what I say with a grain of salt too, but my comments come from years of accumulated data.

I've typed so much on this topic that I find myself shorting my responses to the bare bone explanations, so if there's something you have questions to, please ask.

And to debunk the "its the diaphragm" concern, here's a picture of one. Its on the far left.....and its stainless steel over plastic.

supr

FWIW, I have read 20 psi in many threads. Bliss in numbers? My 1 year old
Airtex puts out 19, with the biglinekit.

trust

well with the new spring I'm getting not quite 15 at idle and 7 or 8 under load on the mechanical gauge, about the same loaded on the in cab gauge but on the hi peg under trailing throttle or idle so not to high for sure now it doesnt sound like never yet below 5 on either gauge so I'm feeling ok about it I guess and I dont need a new mechanical gauge

Thanks!!

klcammie

I know this late. according to blue chip that builds vp's 22 - 23 at idle is ok. 30 or more is hard on the fuel solinod in the vp. i'm running 22 to 23 at idle.

KATOOM

I like Chip and I respect his info. Even with that respect, over the years he has told me things which contradict what he had told me in the past. No comment on that though. And.....no, he does not build them. He has suppliers just as other vendors do. Just not all vendors use the same suppliers. Also, I believe that those suppliers build to the vendors specifications, per say.