I've been having problems with fuel delivery for awhile, especially on long trips and hard accelleration. My truck used to be pretty strong and create lots of black smoke. Then the smoke lasted a second and went to bogging and on the highway white smoke. On long trips it would lose all power to the point of not running on the highway. Just put on my overflow valve an hour ago. Seemed better, but on the highway it just had a very slow, but smoother accelleration with no smoke and low egt's. I got back on the highway and floored it, no power! little bogging.... SLOW.... at about 70 the whole truck started doing the bucking bronco dance until i let of the pedal. So i come home and drill out my fuel line banjo bolt and mount a gauge to it. Bounces around like made, just a blur... averaged maybe 30 or so? Turned off the truck and the needle was now a little hook, from being slammed into the stop stud so quickly. Now what? i have a compression tested, i guess i could rig that up. Whats wrong now? My pump? what do i do now? HELP!

 

Sounds like you need a new lift pump.

I had to replace mine. I sputtered white smoke at the upper rpms, retimed to 15 deg and new lift pump/overflow valve cured it.

I had the pressure tested at a diesel shop, he confirmed the lift pump was not giving the pressure it needs.

I don't remember the fuel pressure numbers for idle and wot.

From what I understand you can't just put a regular fp gauge on it, has to be special type from what he told me, to many pulses as you describe. This is a cummins certified bosch shop.

Side Note: make sure you fuel filter is clean, and rubber return and supply fuel lines are not leaking. Most of our trucks needs the lines replaced.

 

Oh, check your fuel shutdown solenoid, make sure its pulled up all the time with the key on. I also replace mine for grins, and a fuel shutdown relay.

Some report it won't pull up the way its supposed to and results in low power.

 

Hydroseed, you need to have a needle valve installed at the banjo fitting and then the gauge. Just BARELY crack the needle valve to eliminate the oscillations at the gauge.

Make sure you have 20-25 PSI at idle and 30-35 at full song, might full well be your lift pump.

 

Good advice about the needle valve. It is a must. Yes, check your pressures before replacing the pump. Also, this may be obvious but how old is your fuel filter? Any smoke when this happens?

 

Your gauge is wasted, install a new one with a needle valve.
Engine running, pinch the return line with pliers, if the gauge shoots up above 50psi your lift pump is fine.
http://dodgeram.info/tsb/1996/14-07-96.htm has lots of good info

Needle valve installed on banjo bolt