and all 3 Dodge service shops I called couldn't tell me what was normal pressure at that location ....one said 8 PSI was fine because it wasn't about pressure but more about volume?? If you have low pressure to the VP44 can the volume be adequate ?? This is really confusing for those of us not highly knowledgeable about our diesels. Wouldn't it seem logical that Dodge would now the normal operating pressure levels.? They seemed to think 8 PSI was perfect...Doc

 

No... most dodge garages couldn't give you an ounce of proper info on these engines. ANYBODY here will tell you, avoid dodge all together. Didn't we give you all this info on another thread? I mean, not being a jerk, but you should buy a Raptor 100 and take it from there. Where are you located? Maybe a nice Cummins guru will be close enough and willing to help

 

With a stock lift pump and injection pump its should be 17psi at idle. if your running 8 you need to replace your lift pump.

---AutoMerged DoublePost---

Note: its going to flucuate with demand of fuel from the injection pump. BUt when you start the truck it should stay aound 17 PSI. Mine sits at 17PSI when it 40 degress and up and falls when its colder, And there different type of diesel, Kerozene, Reqular diesel no anti gels additives. Then winter diesel wich has antigel additives. I sit at 14psi until its warms up out side.

 

I'm pretty sure employee's of Dodge dealerships are told to tell you that is ok pressure for a few reasons. 1, it's all their equipment will produce. 2, They want you to buy a VP44 from them, and pay them to install it.

You are correct with low volume yielding low pressure. Pressure is resistance to flow, pumps DO NOT create pressure, they create flow. With the same resistance, the only way to increase the pressure is to increase the flow. The Dodge factory block mounted or in tank pumps do not create enough flow to get the pressures that are recommended. Recommended by those that know the VP44 system, not the dealerships.

The overflow valve is set to open at 18PSI. Until that is reached, you have minimal fuel flow through the VP44. Fuel flow is not only responsible for lubrication, but cooling as well. The more fuel that can flow through the VP44, the cooler it will run. Heat is the #1 killer of the electronics of these pump. I'm currently looking for an adjustable overflow valve to reduce my pressure.

 

I just bought a Raptor 100 today..I take no offense to your suggestions...I appreciate all that contribute here. I'm not sure I can install this Raptor myself but will check ot the instr. manual when it arrives. I have minimal mechanical aptitude .....it's suppose to be a quick connect but satill must drop the tank I imagine..

 

I did not install my airdog myself but, I'm almost positive they did not drop the tank for the install. On the other hand, when I installed new fuel module & draw straw, i lifted the bed off opposed to dropping the tank. I have a winch setup overhead but it can be done w/ 3-4 guys. The bed isnt heavy, just big. 6 bolts, ground wire, and tail light connections.

 

When you adjust it...it probably doesn't take much to get the 18 PSI I would imagine. I plan on setting it at 18 PSI at idle..under load it should be 16 with the overflow valve open for cooling. Since my pump is in the tank they have to drop the tank to finish the hookup..at least that's what they said at the performance diesel place that I bought it from....Doc

 

The best thing to do would be either remove the in-tank pump from the fuel module and add the Vulvan Draw Straw V, its very simple and easy to install but is one of the best upgrades i have made so far. Or get the whole unit from them, Modifed Liberty Fuel Module. This has the draw straw already in a new fuel module. If the Raptor 100 install is the same as the Airdog 100, the connection for the supply line is on top of the fuel module, so yes the intank pump has to go. Also, the harness that it connects to is needed for an aftermarket pump(Raw, correct me if i'm wrong but i think the dealer fix "intank pump" adds a harness that extends the wiring back to the tank that is not necessary anymore)DrawStraw™ V HiFlow
I still stick by taking the bed off is easier than dropping the tank. You just need a few extra sets of hands to do it. If you are having a shop do it, just be ready for a little extra cost in time/labor for them to do one or the other.

Hope this helps, if you plan on doing it yourself, just post any questions you have or PM me.

 

I spoke with a young man that installed an Airdog 100 2 weeks ago..he is familair with the project and a decent fellow so I will just take it to him. I have minimal tools and my expertise is very dubious I just hope I haven't already smoked the VP 44 Even if I have, I at least know that now i have the proper pump to maintain a new injector and not some junk that lasts 2 years. Thanks for your guidance..Doc

 

You would know if you smoked your VP44 they generally throw a code on there way to retirement. And if you smoked your vp44 your truck wouldent run. or run worth a damn. Im replacing my entire fuell system this summer with FASS and a Airdog. My VP44 just got replaced 50K ago glad the previous owner paid to have it done instead of me forkin money out and doin it my self. Good luck, hope that fixes your problem