How do you know when VP44 is dead?

[RCotte]

I 've been working in my truck again today trying to get it running. I devised a temporary fuel reservoir for the lift pump with a 3/8" fuel line attached dirctly to the suction fitting. This is giving me inmeddiate primimg for the lift pump. I am getting 10-15 psi during the brief moment the ECM puts it on.



Then, I loosened injector lines no. 1,3,4& 5. Bled all the air from them until I got a steady stream of fuel from each one. I did this 4 times.



No smoke coming out of tailpipe. I suspect the VP44 is not putting the pressure needed to overcome the injectors. Does this thing could fail all of a sudden or gradually? Worst, could it be possible that it works sometimes only? Maybe there is some other component inside it which prevents it from "stroking" the right amount of fuel to star up?



I need ideas or suggestions. I am out of ideas at this point. Fuel is reaching the injectors but the thing won't start.



The lift pump does not enter in the "second stage" after the engine fails to start. Could it be an electronic problem?



Please help me!!

 

[HVAC]

Relay?

You probably wouldn't have found any fuel at the head were this the problem. But there is a fuse in the fuse box and a relay in the relay box that power the VP44. This is what stops the engine when you turn the key to off.



Give it a try anyway.

 

[Lsfarm]

If you are sure that there is no air in the pump and lines, then either the pump has died, or there is an electrical problem.



The injection pump has electronic control. That is how we turn them on and off.



Pumps without electronic control have a pull knob or lever to shut off the fuel to kill the engine. Many farm tractors work this way



You might have an electical problem. If the electric signal is not getting to the pump to open the fuel solenoid, then even if the pump is good, then it can't make pressure. Have you checked your fuses?



I'm not sure where to check to see if you are getting the correct electical signal to the pump.



I'm afraid to say that if I were in your position, the next step is to take it to a Cummins or Dodge dealer !!!



Best help I can give, I hope it helps!



Greg L

 

[Doc Tinker]

I found out by accident about the relay in the power relay box that HVAC is talking about. I was able to get fuel from the injector lines, when I cracked them, while the relay was out of commission. It about drove me nuts for a while.



Doc