jruthven

In order to plumb the fuel line to the new pump, you have to remove the fitting from the old pump inlet, and put it on the new pump at location one. Use some pipe dope on the installation to the new pump considering that it is not a flare type fitting, and go from there.

boeingguy

The new pump inlet appears much larger

jruthven

The fitting that connects the fuel line to the lift pump will fit perfectly in the inlet of the new pump. Once that fitting is screwed into the inlet of the new pump, connect your fuel supply line to the fitting.

gcliburn

I have read where the diaphragm pump is about 5 psi. But how do the piston and diaphragm compare in flow rating. Seems like that would be more important than pressure even though pressure is part of flow. My 91 runs fine but i wonder if insufficient supply is why i have slow acceleration at higher speeds especially when loaded.

jruthven

Well, in short, there are two different types of piston pumps you can get. There is an actual low pressure model, and there is a high pressure model in which you can put a lower psi regulating spring. The higher psi pump with the regulating spring produces higher flow due to larger piston diameter as opposed to the actual low pressure pump. My diaphragm pump saw psi as low as about 3psi at WOT, and since installing the piston pump I have seen nothing below 12psi. The truck is a lot more peppy in general, but the power is right there at higher speeds.

gcliburn

So 2 more questions. How likely is the ve pump to leak when the supply pressure increases on the current seals in it. And any advice on where to get the pump i should need. I am not trying to build a hot rod or anything. Just a good reliable truck to tow and haul on the farm.

jruthven

The VE pump can handle a maximum inlet pressure of 18 psi if I'm not mistaken. As long as your pressure doesn't break that threshold, the seals will be fine. I would recommend installing a fuel pressure gauge if you don't already have one, as it allows you to keep an eye on these pressures. As far as where to get the pump, check out "the hungry diesel". They sell a complete kit that includes all genuine Cummins parts, and they are really nice people to do business with. The pump that they sell you is the true high volume low pressure pump, which is ideal in my opinion. I hate the idea of hot-rodding my truck, and am only after reliability as well. Installing the piston pump has made a huge difference in the overall responsiveness of my pickup.

jruthven

I forgot to mention that you can choose to have a 12 psi regulating spring put into the pump, or a 15 psi regulating spring. This way, you should never see pressures high enough to blow any seals in the VE pump, but a fuel pressure gauge is a nice thing to have.

gcliburn

Thanks for the info. Really appreciate it

jruthven

Absolutely! I can't take too much credit, as all of the guys who commented on my initial thread have taught me so much.

CrabWalker