97c

I have a 97 12 valve that has a low power issue.
Truck has an auto trans, also has 4K gov springs, full forward stock plate, full forward star wheel, afc housing slid full forward as well. I have replaced all filters. Also did fuel pre-filter delete, and have installed a new lift pump as well as a new overflow valve.

truck barely hazes any smoke when punched going on the highway and has minimal acceleration.
truck does have 318k miles. Could the pump be bad? Or may have a fuel restriction inside the tank screen?

AlpineRAM

Or it could be that the shutdown solenoid does not pull up all the way.
(After starting the truck, push the lever up by hand, go for test drive. If it works better rebuild solenoid)
Or it could be that you get aereated fuel because the tank module fittings rusted through.
(Connect long piece of transparent hose to water drain outlet of fuel filter, route into fuel filler neck, start engine and open fuel drain slowly, watch for foam in the hose.)

HTH

97c

i will check the fuel shut down and give an update

97c

i checked the fuel shut down and it is coming all the way up. I guess next I will put a clear hose on the drain. I assume you run the hose to the filler neck?

patdaly

Though you have installed all that stuff, do you know what fuel pressure the P7100 is getting?

Make sure you have at least 22-25 at idle and 32 -35 at WOT under load.

97c

idle pressure is 10-12 in park, and get to about 22-24 under WOT. Also about 24 psi at 2k rpm in park

97c

another update. I suspected overflow valve could've been bad, even though brand new, pinched return line fuel pressure stayed the same. Going to pull the bed and look at in tank screen

patdaly

There you go!

While you are there, also inspect the steel lines coming out of your fuel module, especially in salt climates, they get rusty, and start flaking, after so long, a pinhole can develop and cause air ingestion. After a while, Dodge changed them to plastic and all remanned units started coming with Plastic.

If you want to verify a problem before pulling the bed, just remove the rubber line for fuel feed at the engine and run a 3/8" rubber hose into a 5 gallon can of Diesel, prime and re-check your fuel pressure, that will verify the issue is either at the tank or in the lines leading up to the lift pump. You can leave the return line hooked to your regular tank, you won't be running it long enough to overflow your tank.

97c

well pulled the bed and cleaned the screens. Weren't too bad, put back in and still low pressure. Pinched return line and pressure jumped up over 30. I guess I didn't let it run long enough last time. Going to get a new overflow valve. I road tested with the line pinched and runs a lot better

patdaly

Verify your gauge, if your lift pump is putting out the correct pressure it should have pegged a 60 Lb gauge almost immediately.

Just for giggles, when you say you replaced the lift pump, you do mean a stock, block mounted lift pump not one of the fancy aftermarket electric "performance upgrade" pumps, correct?

Also, do you know you have the right mechanical pump? They do sell a low pressure piston lift pump for the VE guys.

97c

i replaced it with a stock block mounted pump. And it is the correct mechanical pump. And the pressure the highest I've seen at idle was about 50-52 pounds. I guess I should've been more specific. The gauge I have is a Matco 100 psi gauge