Another lift pump question
 

Well my question is whether or not I need a new lift pump??? I've been reading lots of the threads already posted and it seems that everyone with a bad lift pump has some other problems... The truck runs fine... all the time! Cold weather... everything...
The problem is my fuel pressure gauge reads about 9 or 10 at idle but will drop to 1 or 0.5 lb @ WOT!!:scare2:
I just rented a mechanical gauge from auto zone and it says about 7 @ idle but will drop to 2 just by stopping the throttle in park sittin in the shop... However like I said never have any problems with any shudder or anything... Runs smooth always fires up immediately when starting it! Also had auto zone scan the codes and the only code was 0234... over boost or something weird, only boosts 26 or 27... But anyway thats another discussion...

Money is very tight so I don't want to just buy a 400 to 500 dollar pump if I don't need to...( If I do have to buy a pump it will definitely be an airdog, fass, or raptor cause someday I plan to take it 500hp...) (and i've heard that stock is junk)
Any Advice??? Thanks!!!

If your pressures ever drop below 4psi at anytime you are risking the VP44. This will cost you big money in the end if you wait and still might even if you fix it now. Damage may have already been done.

The stock is only just barely adequate for stock horse powers when everything works perfectly and that's about the nicest thing that can be said about it. Throw it out, fuel lines and all. I would also add the MTUSA belt driven lift pump to your list of pumps to be considered.

Hook up a pressure gauge ASAP that you can see at all times. You can do this for less then $50 for a mechanical gauge and they are preferred anyway over electronic.

order a raptor for a vendor on here and be done and hopefully save your vp but if you don't act soon you will need a vp and a raptor:argh:

i had the same problem, your pressure sould never go below 5psi at WOT. Get a new lift pump(AIRDOG). Unless you want to buy a VP44 and lift pump when it doesent run. Save your self the cost of the VP and upgrade the lift pump.

Thanks guys!
Was afraid thats what i would hear!:argh: Just thought maybe there was another problem since everything worked well!!!
Anyway... Between the the Raptor 150, the Airdog 150, and the Fass 150 which is best?
I am leaning towards the Airdog or Fass cause of the 2 filters and how easy they are to change... Raptor doesn't have those i understand???

Meanwhile i will gingerly drive the truck and try to stay above 5 psi.

Another question... Uncle Bubba u say damage may already b done to the VP?? Is there a way to check that to see if its ok?

Only way to check for sure would be to have the pump bench tested. Your truck will drive just fine with no lift pump at all, this is why the gauge is so important. Your VP could also run just fine if it's goin bad. Some things you may notice is decreased fuel mileage, low on power, hard starting when warm, rough or erratic idle and few hundred other things. The one thing you can count on is that if damage is already done it will get worse with time.

I wouldn't worry to much about the VP right now and focus your funds and time on getting the LP and fuel supply fixed up first.

i have a fass on my first gen...not impressed i just bought a airdog II 165, comes with everything you need, even the stuff for in your tank. and the damage uncle bubba is talking about is a diagham in the VP if the fuel press. goes too low you will strech it and risk putting stress cracks in it which will lead to it breaking.....

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feel free to correct me if i'm wrong i don't know a whole lot about 24v

Well I just got my brand new Raptor 150 put on... And it isn't pumping fuel!!!!!!!!!!!!!:argh::scare2::argh::dang:
Tried pressurizing the hang out of the fuel tank, Can get fuel to go through it then but as soon as I let the pressure off the fuel tank it quits coming!!! :argh::argh:
It seems like it isn't sucking it out of the tank.

ANY HELP???? PLEASE!!!

was your truck fitted with an in tank pump? If so you gotta drop the tank and do a draw straw, or sump it.

Assuming everything's installed correctly (:humm:) sounds like a restriction somewhere. What about the filter?

ditto...if you look at the drivers side of your block, is there a lift pump there? if not, then there's a good chance that your lift pump is in the tank, in which case you need to go draw straw, or get the module to replace your in tank pump...

The in-tank pump is a flow-through design.

not very well though...........very restrictive

here is some good info on the intank pump


https://www.dieselbombers.com/5-9l-2...dont-walk.html

Mine flows pretty good. I can run with it disconnected using my helper pump and maintain 5psi through a dead in-tank lift pump.

helper pump?..........please explain

It's a Walbro FRB-22, 10psi, 40GPH, inline ahead of the stock pump/tank. It's normally switched off:

http://stuff.is-a-geek.net/PhotoAlbu...ics/CRD_27.JPG

I can't figure out why you need all that pressure and GPH. It's just pumping 99% of the fuel back into the tank through the regulator. My truck burns less than 4 gallons/hr. at cruise and needs some more for cooling/return flow. The CP3 needs positive pressure at the inlet, that's it. I run a helper pump as a backup, to help when it gets really cold and to potentially support additional fueling mods. Someday, maybe.

[QUOTE=NadirPoint;477323]I can't figure out why you need all that pressure and GPH. It's just pumping 99% of the fuel back into the tank through the regulator. QUOTE]

80% actually is what it is ^^^^^


A CP3 doesnt need near the flow for cooling and lubricity as a VP-44 does

As long as you maintain a certain inlet pressure it will use whatever it can flow for the engine and self-cooling. What's the 80% excess pumping capacity for?

80% excess flow is for cooling and lubricity of the pump......its paramount for the VP, not so bad for the CP3 since it has no electrical components in there

Thanks guys... I was really startin to get pissed when the raptor wouldn't work... Finally figured out it does the in-tank pump... I can't believe the guy I bought it from was dumb enough to get a replacment pump from the dealer...
Anyway it was very simple to fix cause the bed was off so I could repaint it... I actually just pulled the hose off the inside and put a piece of 3/8 rubber hose down to the bottom of the tank beside the big dumb plastic piece that's in there... I left all the connections on top outside the tank just like they were... Will just have to be careful not to get below about an 1/8th tank or so... Go around a corner or something and it sucks air...
Has been working great!!! 17 psi at idle and 14 at WOT. :tu: