TNutcher

hey I installed a HPFP 150 awhile back and it'll build pressure just under 20 when the truck isnt running. before i would start it and it would idle at 18 and wouldnt go below 13 WOT. I thought it would be a little more solid pressure but it was ok. I put jammer 5 injectors in about a month ago and now i can drag it down to 8psi and it idles at 14. it was fine for a week or two after the injector swap (wouldnt drop below 13-14) but now its down. I Figured the 150 pump would suffice.... is it a wussy pump or do i need to do something to the fuel lines?? i've heard of a different pickup or modifying the pickup but dont know much about it... Help me out here guys =D
Thanks,
TNutcher

SilverSootXpres

8psi under WOT is plenty of pressure to supply the VP44.

It won't provide any more volume of fuel at 8psi vs 14psi.

Does the truck runs strong and smoth under WOT?

I have a FASS 150 w/ DD Stage 3 (100hp), and I drop to 9-10psi under WOT, whether it's in front of an eliminator or drag racing. Idling I get 17psi. 15psi down the highway at 72mph/9psi of boost/2200rpms.

You shouldn't have anything to worry about until you get below 5psi under WOT.

WildBill

Reading fuel pressure at inlet of VP? When did you last change the fuel filter?

Diesel-Dan

When we see large pressure drops under WOT on trucks, its usually 3 things:

1. Restriction (OR sucking air) on the feed line to the pump or any restriction before the gauge Tap. (IE: Filters, internal hose flaps (Rare but happens), pick-up in tank clogging up or cracked)

2. Debris in the pop off regulator in the pump. I see the main reason for this being WAY too much thread tape was used or hose debris from when it was cut on install and the line was not flushed.

3. AND the most common issue: Gauge not reading correctly. Especially if you have an in-line isolator or electric gauge (Edge Juice is one that tends to read low under WOT from what i have seen). Check the gauge and confirm its reading correctly. This one happens all the time.

There could be other factors as well...but this will get you started.

TNutcher

thanks all.
Its an isspro mech gauge with no isolater only a needle valve and i opened it to make sure it wasnt the gauge. I'll check the filter and the pickup. would a draw straw or anything like that help?? The gauge is also tapped in the post filter 1/8" ntp port on the filter housing. The reason i'm concerned is because i've seen the pump put out only 19-15 psi as its lowwest in the form i currently have the truck... only recently did it start dropping for no reason and i assumed the HPFP is a good pump that wouldnt tend to do that. Thanks for the replies i'll check back when i check the filter/pickup.
TNutcher

Diesel-Dan

Try Pulling fuel from a 2L Coke Bottle or something similar.....its an HPFP so you wont drain the bottle like you would with a FASS. See if the pressure improves or not. If is does, this points towards your tank. If it doesn’t, it takes the tank out of the equation.

Also, opening a needle valve all the way on a gauge that is possibly reading incorrectly won't help you out. I would suggest getting a known working gauge and double checking its operation to eliminate the gauge completely.

I would also contact you dealer with your SN info and have them get in touch with me.

thellums

i had a similar problem recently with my Glacier pump. After alot of pocking around I finally found out that I had gotten a bunch of bad diesel and it clogged the pump inlet filter. Just removed the pump, sprayed it out good, installed an in-line filter and now it's all good.

TNutcher

Well i changed the fuel filter. that gave me back about 1psi so i took off the hoses and blew them out and blew air into the tank. that helped out a little more.

Now it wont go any lower than 11 or 12 but it still seems low and drops easily. I'll see if i can try a different gauge ASAP.

About the pump pop off regulator... is there anyway to check that myself or would that void the warrentee??

Also, what is everyone elses pressures with this pump (HPFP 150)?? and type of setup power wise??
Thanks, its gettin better!!
TNutcher

Diesel-Dan

Anything new?