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I have a 2001 Ram 2500 Cummins 4 by 4 automatic and I cannot get my fuel pump to a cycle on relays good fuel pump is new I can run a hot wire to it and it runs but the truck will not start is there a fuel pump shut off switch somewhere I still annoyed or something that I should check and where would it be located

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What kind of pump. Does it plug in to trucks wiring harness where your factory pump was. When starting the truck don't power on your pump, i a VP44 doesn't like pressure on startups. Lift pump needs to run as soon as truck starts. 

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Wait to start light coming on? If not the ECM is not booting up and will not turn on either the lift pump or the VP44.

 

Lift pump should be directly controlled by the ECM. The VP44 is turn on by the fuel pump relay in the PDC.

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I wired this precision inline replacement to the original pumps wires, its not getting power so I ran my own power from toggle switch and it runs holds good 25psi hardly have any fuel coming back on the return,wait to start is coming on and looks normal but tbe truck will not start or run after started with help from fluids im stumped changed cam positioning sensor and pump and relays and was wondering about throttle positioning sensor should I change it but i would like to know what the resistance should be at the pins so i can check it before spending 230.00 which is what I am getting quoted from autoparts

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Your fuel flow back to the tank at 25 PSI should be and the truck not running should be strong.  How is the flow at the injection pump?  check this out to test your fuel flow.

    

The throttle position sensor, also known as an APPS (accelerator peddle position sensor), can be tested with an OBD II scan tool that can read live data.   With live data you can watch the % of throttle opening which should be smooth and not jump when  depressing the accelerator peddle.  Do you have any codes?

The Timbo's APPS for sale in the store here.

 

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2 hours ago, chris1980miller said:

it runs holds good 25psi hardly have any fuel coming back on the return

This does not sound good, approximately 70% of fuel entering the pump is returned to the tank through the overflow valve and fuel return line. :think:

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I have to repeat and ask what is this precision pump? It should be returning fuel to the tank.

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2 hours ago, chris1980miller said:

I wired this precision inline replacement to the original pumps wires, its not getting power

 

Not good. This is why all pump manufactures have moved to relay protected power. This way the load is not place directly on the ECM. Now the excessive load has burned the lift pump circuit on the ECM. This is repairable but for a price of course.

 

2 hours ago, chris1980miller said:

but tbe truck will not start or run after started with help from fluids

 

Excessive high lift pump pressure will prevent starting. Leave the pump off and then start the truck and then turn the pump on. Again the ECM does a 50% duty cycle during cranking to reduced lift pump pressure to about 7 to 12 PSI. This aid in starting. Again it would be a good idea to repair the ECM and then wire the lift pump with a protection relay like AirDog and FASS do.

 

2 hours ago, chris1980miller said:

was wondering about throttle positioning sensor should I change it but i would like to know what the resistance should be at the pins so i can check it before spending 230.00

3

 

 

It's not about resistance. Here you want a live data tool and measure the TPS signal. It's about the voltage that the ECM sees and the ground triggers (IVS switches).

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Thanks everyone for the information im going to send my ecm to get fixed but why cant I just supply fuel to this sucker add pressure and be running somehow i am kinda bummed that the computerized stuff is so fragile

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As you have discovered you can wire around the ECM to power the lift pump but you bypass the safety feature that shuts it down in the event of a wreck. You don't need more fuel pressure, you have more than enough. As far as the electronics any electronics that get bad power, mainly AC voltage, are going to fry. Your charging system needs to be in good shape. If I were you I would get the trouble codes read and see what the truck is trying to tell you is wrong. Throwing parts at these kind of issues can get expensive before you find the real problem.

 

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