Lift Pump vs Electric

[LostSoul]

I am very seriously thinking about getting rid of the Mechanical lift pump and replacing it with an electric as I think that the current lift may be causing some of my Fuel issues. Part of the issue I am up against is, the truck is a 95 with the motor from a 93. The Mechanic that did the swap (before I bought it) changed over the Turbo and lift pump, but left the Rotary pump on the motor. I am being led to believe that the lift pump may be weak as we have the Rotary pump turned up with very little power gain and almost no smoke. What was said to me was that with the changes that were made to the pump, this truck should be belching black smoke. I do have another lift pump to swap on, but it is not the same style, it has the lever for priming where as the unit on the truck has a plunger. Worst case the lift pump off the 8.3L I am looking at snagging injectors out of is there and it appears to be the same as mine. What suggestions are out there?

 

[averagef250]

Why in the hell are you swapping parts from so many strange oddball things???

I don't know what you have going on, but a piston lift pump from a 94+ will not work on a VE pump engine. A VE needs 3-10 PSI fuel pressure, a P7100 needs 25-50. A VE has it's own built in lift pump, a P7100 does not.

Don't ask unanswerable internet questions- Get a fuel pressure gauge, install it and see what the hell is going on before speculating what might be going on.

 

[LostSoul]

First let me say this again, I did not do this engine swap. The previous owner thought he was doing a good thing by putting a lower mileage motor into his truck. What he did not know was that the mechanic went and swapped a 93 engine without changing over the P pump from the original. The lift pump mounted on the back of the block has a rubber bush button to prime. Older 93 style trucks I have seen have a lever to prime. The reason I was looking at grabbing the injectors from the 8.3L is they would have been free and would flow more fuel then the ones in the motor. I have not had time to test the pressure and figured if I asked I might get some help, not someone telling me I am asking an unanswerable internet question. If you do not understand what was asked, ask, if you do not have an answer then so be it, but do not give me attitude for trying to use a resource at hand.

 

[ameristar1]

Ok, to eliminate some confusion, going to something like a FASS system or AirDog with an electric pump does not hurt and will give room to grow for future upgrades. Going to 8.3s is unnecessary, there are more than enough injector upgrades out there to flow the fuel, but the airflow must be matched so you don't have a smoky, low performing mess. If you can get the P pump and hardware off the other motor and swap it on that's fine, but the VE can be made to run with a spring kit, turned up settings and more timing. What do you want to do with the truck?

 

[LostSoul]

The adjustments have been made to the VE and that is why I think I have lift pump issues, I am not getting much if any black smoke and have not gained much at all in power. I thought about the P pump swap, but the guy wants way too much for it and I am not looking to make that much power. As for getting air into the motor, I have another turbo for it ,but I want to wait until I figure out the fuel issues before I start adding air.

 

[argve]

I would say check the pressure coming from the lift pump first - let's troubleshoot the heck out her before sealing it's fate...

I'm not too knowledgeable on the older VE systems so that's where I would start.

 

[oly_fab]

Why in the hell are you swapping parts from so many strange oddball things???

I don't know what you have going on, but a piston lift pump from a 94+ will not work on a VE pump engine. A VE needs 3-10 PSI fuel pressure, a P7100 needs 25-50. A VE has it's own built in lift pump, a P7100 does not.

Don't ask unanswerable internet questions- Get a fuel pressure gauge, install it and see what the hell is going on before speculating what might be going on.

You can use the pump from a p7100 but you need a fuel pressure regulator or you can go low pressure piston lift pump.

http://www.dieseltruckresource.com/...q&nr=168&catnr=20&prog=1&lang=en&onlynewfaq=1


Just do a google search for piston liftpump upgrade.

Have you changed the filters? nobody has mentioned that, do the 94+ have a screen in the tank?. If your filters are good check the L/P pressure. I think I remember seeing 5-7 psi is normal.

Stu