I have a 2001 dodge ram 2500 with the 5.9 diesel. I just replaced the fuel level sending unit the other day. I dropped the tank, cleaned it out, replaced the sending unit and the rubber seal the lock nut tightens down on. I bled the air from the banjo fitting connecting the fuel line to the injector pump. After that I bled the air from each injector except number six which is nearly impossible to get to. I fired my truck up and drove it around. It ran normal for about two or three minutes then it started to run super rough like it was starving for fuel. Surging and lacking almost all power. I would pump the pedel trying to give it more fuel. The fuel would catch up but my truck would shoot out a bluish white smoke. After all this, I would shut it down. Now I would have a super hard time starting it back up. If anyone has an idea or info about my situation, I would appreciate any input. Thanks

 

Are you certain you tightened the banjo fitting and all injector line nuts very good? Not trying to second guess, but forgetting does happen...has to me anyway.

 

Sounds like you are getting air from somewhere. My guess would be the banjo fitting on the tank side of the pump. Anything loose on the upstream side of the lift pump would be leaking.

Rick

 

Ya, I just went through and checked the fittings and snugged them up. Thank you for the suggestion. Do you know if the fitting that connects to the tank is a common problem for air leaks after it has been opened up?

 

The tank fuel line quick connect would be one I'd look at. Not sure how difficult it was for you to remove but I've heard many tales where they just didn't want to come apart and a tool was used to pry. I also think there is an o-ring in the fitting too. I'm guessing that you dont have a fuel pressure gauge and I'm also guessing that you have the OEM lift pump or at least a replaced OEM lift pump. If so then what may have possibly happened is your lift pump was doing a poor job but the truck will still run because the fuel lines have a prime which keeps all the lines full of fuel and fairly easy for the lift pump to feed the VP, especially if you tend to keep the fuel tank above 1/4 full. Then by opening up the fuel system you have lost the prime there by now asking the lift pump to work harder at pushing out entrapped air. So before you go tearing things apart, I'd try to find a fuel pressure tester gauge which taps into the banjo fitting shrader valves at the fuel filter housing inlet and the VP. That will tell you whats going on. But you can check the quick connect fitting too. You may try cracking some injector lines while cranking it over to see if anymore air purges out.

 

I just hooked a pressure gauge up to each banjo fitting shrader valves. I bumped the starter engaging the lift pump (FASS Direct Replacement Lift Pump). I have about 17lbs on each side of the filter. I then started the truck up and my gauge reads 0lbs. Is this normal?

 

NO! Sounds electrical to me. Try wiggling all of the connections that you worked on.

Rick

 

the only electrical I worked on was the sending unit in the tank. I replaced it. I did disconnect the batteries.

 

Neither of those should give you this problem. I will have to defer to the experts on this one.

Rick

 

hook a volt gauge to the pump wiring to see if you loose voltage when the engine is running, if you dont loose voltage, then its either a bad pump or possible hoses mixed up

 

What nick said. On some second gens that I ran AD's on, I had to run a power line with a toggle from the battery to get the pump to work right. Something to do with the ECM power supply to the OEM pump.

 

All power to the OEM fuel pump connections come from the ECM. The ECM tells the fuel pump to run in pulses during engine cranking and then to pump full time after the engine starts. Its not uncommon for the ECM to freak out and stop powering the fuel pump, especially when changing to an aftermarket fuel pump that taps directly into the OEM ECM fuel pump wiring connector without using a separate relay, which is why some guys have to hard wire to the battery. The only problem with doing this is that then there is no longer any priming or bump running of the fuel pump, only on/off. As nickg stated, test the fuel pump connector when you're reading ZERO fuel pressure and see if the ECM is still sending power. If its not then make sure all the connections are tight. You might even try disconnecting the batteries again for at least 1/2 hour and turn the key to ON so that you fully drain the electrical system of any residual.

 

I tested the fuel pump connector when my truck is running. The ECM is sending power to the Lift pump but my gauge is reading 0 pressure. When I just bump the motor to engage the lift pump I am reading around 18lbs of pressure both sides of the filter. How many lbs of pressure should I be reading?

 

How do I check to see if my lift pump is working properly?

 

How exactly are you testing the fuel pump and what kind of fuel pump do you have too? Also when you're reading 18 volts to the fuel pump, are you testing with the fuel pump connector connected or disconnected to the fuel pump? I'm not completely sure about the voltage either. 18 seems to high where I'd think you should be reading no more than 14. I know there's lots of questions but figuring this stuff out over the Internet isn't easy either.

It may be way off base but given that you disconnected the batteries, are you sure that you got both of them hooked back up nice and tight with good connections? And are you positive that both batteries are in optimal condition? One bad battery will sometimes be hard to detect but will cause all kinds of potential issues with you chasing your own tail.