Need help ASAP, fuel pumps and pressure questions
 

So, I'm not the first guy to lose a vp44. Lift pump went, bought a raptor 150, by then the damage was done, within 2 months, the vp quit. I bought an hr vp44 from iis, installed, and cannot get my truck to fire, and when it does have fp issues. Had the truck idling, set the psi on my raptor to read about 17-18psi at idle @ the vp. All was looking well... throw it in gear, pressure drops to 10, truck stalls. And when I go to re start it theres nothing happening. Even though I am getting 18psi on mechanical gauge at the vp when raptor runs its cycle. I have my tank out right now to remove the in tank replacement pump installed by previous owner and am wondering if this pump could be messing with my fp? It just seems so strange to me that the truck would stall out with 10psi, and not want to fire back up reading good pressure at the vp while cranking.

go with an air dog to feed that kind of a pump

the raptor is basicly an airdog with no filters so it should be fine it was fine for my cummins. iirc the intank pump doesn't like to flow through itself too well so installing a draw straw or something similar should help. 10 psi is about where you would want it at WOT not idle. did you get a bigline kit for between the filter and the pump?
how is the fuel filter?
you aren't sucking air from somewhere are you?

I did away with the in tank pump, have 1/2" lines from tank to canister (made custom draw tube) and that seemed to do the trick... BUT, I drove about 10 miles to my brothers house, checking stuff out, truck runs great, plug scanner in only to have 1689 and 0216 code. Now I'm puzzled. I notice my fuel pressure fluxuate after I parked it, but that seems to be intermittent. I swear that I hear that breaking up sound (you know it if you've had a truck lose a pump) but no RPM or power change, I'm just afraid I'm running the pressure too low, but I can't tell I only have mechanical gauge under the hood.

I cleared the codes, reset ecm and apps after I installed the VP and had no codes after first test run. I DID NOT DAMAGE OR LOSE THE KEYWAY ON THE PUMP, iis doesn't want to tell me anything other then that, but I am telling you right now I can see the keyway with a mirror and pump nut torqued to 125.

What do you guys read for psi when your pump cycles? Mine seems so be a little over 20psi if I bump starter... otherwise I am getting 18-20 at idle when all is well and about 12 at wot. My VP is under warranty so maybe I should just do what my buddy is saying and stop reading codes, just beat the dog snots out of it, and when it lets up send it back? haha I don't know, vp doesn't even have 50 miles on it, I am a little upset right now to say the least.

that pressure is great, anything over 8 they say is good but on mine i liked to keep it up to around 12 at WOT. mine was also at 19psi at idle and it would fluctuate some when the engine was cold i had decided it was the cycling of the grid heater bringing voltage down in the system. does it fluctate with the voltage?

also the hrvp44 runs a little different than a standard vp so that may be what you need to get used to. did you ever change the factory fuel filter?

Codes will not clear, now getting dead pedal... Installed in cab gauge running 19psi at idle drops to 12 at half throttle, I didnt even want to drop the hammer figuring the pressure would go to 0... Looking like iis owes me a pump, even though they are still hung up on thinking i broke off the keyway

Please educate me, Who/what is iic ?
If I was in need of a vp44 I would only purchase one from a reputable Diesel Bombers member. I just don't think one of our members would ever screw us.
Best of luck with your problem.

IIS = industrial injection. And i dont think they screwed me, the pump is warrantied either way.

Still just trying to figure out why i could have 20psi at idle and drops to 4 at wot...

Did the new pump(HRVP44) come with a new VP44 FUEL OVERFLOW VALVE . That check valve regulates flow.If it is stuck open there goes the pressure down the tube.