Ok here is the problem. The fuel pump on my 99 Dodge ram 3500 5.9L turbo went out. Seems to have been the stock one. Vehicle has 265k miles on it, i have put 1300 miles on it no problems what so ever.

I was driving down the road about 40mph and engine just shut off. Got it towed home, and found it was the fuel pump. Ok i replaced it and the fuel filter. I bleed the fuel filter of air, disconected the low pressure line that enters the VP44, and got fuel pouring out of there.

Today i loosened 4 high pressure lines that feed the injectors. One at a time, and got fuel pulsing out of all 4 (just one open at a time) when try to start the engine.

I get the p1688 code now, but the vp44 is still pumping? Code came after i decided to unplug the diablo power puck and just run stock.

Will not even attempt to turn over, just starter going and going. I am lost on what to do next. Please help.....Thanks

 

weird. so you leave the key on and fuel is pumping out right. then tighten everything up and still nothing? should fire up. maybe something internal on the vp44 is junk? do you have a fuel pressure gauge? what is it? i've heard of guys saying once the lift pump goes the vp44 is not to far behind.
double check the lift pump wires. not sure but maybe the vp44 is sucking fuel from tank. if it can do that? maybe someone with a vp44 truck will chime in. i've only helped replace the vp44 once. it's gotta be something minor, we hope.

 

I can hear the fuel/lift pump working. It works for the 20 or so seconds after u bump the starter. I dont have a fuel pressure guage but i can see i should have adequate fuel pressure. The new pump is not a stock and was $350, says new and improved, lol. Also the engine bay is dirty but the current VP44 in there is not as dirty so im thinking it my not be the original. But with the fuel pulsing out of 4 high pressure lines, i would think it should be trying to start???

 

Should i leave all 3 or 4 high pressure lines cracked open at the same time and try to start it? I only did one at a time.

 

I typically open #1 at least a full turn and #3 and #4 about 3/4 turn. It'll crank, sputter fuel out #1 while dribbling out #'s 3&4, then fire and run really rough. I tighten 4,3 then one and the idle smooths out. It helps to have someone cranking for you so you can be under the hood with a wrench. Be careful of the belts and fan......

 

Ok i will try this approach tomorrow, if the rain lets up. Dumb question here, but i assume #1 is in the front of the truck, not toward the back under the dash right? Sorry i come from V8 muscle car world, This truck was bought to let my "race car" sit in the garage in the winter and to trailer it around.

 

Yup, #1 is to the front. I would also recomend priming all the way from the fuel filter to the vp. Have in your hand a 17mm socket with a 3" extension. Loosen the two banjos on top of your fuel filter and the banjo on the side of your vp. Have someone bumb starter but do not crank. Let that pump run and start closing banjos when the fuel starts shooting out of them. You can turn the key back and re-bump the starter as many times as you need to get the fuel moving. When you start cranking, after you get good fuel to the vp, the book says not to crank more than thirty seconds. I feel that's too long myself. Just don't crank it until you roast a starter or kill your batts. Toss a bag of kitty litter under the truck or do it in the dirt for a dust-free surface. Once you get it primed and running, let it idle for a while to ensure all the air gets out. One note, DO NOT PRESS THE ACCELERATOR PEDAL WHILE CRANKING. The object here is to get the air through the vp. Air compresses and reduces the pressure in the fuel lines so you you want to pass as little as possible with each stroke in the injection pump (my theory). I'm no injector or injection pump expert, but I know you should not do it while cranking.

 

Ok well looks like i will restart the priming/bleeding thing tomorrow. I did not do it the same way as everyone has stated. So im hopeing there is still just too much air in the lines. I dont know why it would still give me the P1688 code if it is pumping fuel past the VP44 and the code only came after unplugging my sport puck and going back to stock, weird.

 

I wish you the best of luck. mine did the same thing.....never restarted. well not till $1K later.

 

Im hopeing it does not come to that. Was yours still pumping fuel past the VP44? cause that is what is throwing me off. If the VP44 is bad, it should not be pumping past it correct?

 

My 1688 was the kiss of death for the VP44. It would pump enough to start and idle, but would die when I pushed the pedal. At least it got me off of the two lane road.....1200 miles from home.

 

well if it comes to it, where do you guys recommend i get the new VP44 from?

 

do a few searches on VP44 info... you will find loads of info

VP44 pump is cooled/lubricated by fuel it's pumping. so if/when lift pump goes out... VP44 is deprived of fuel volume necessary to keep itself healthy.

VP44 is capable of pulling enough fuel volume to keep running without lift pump. so it basically destroys itself due to lack of fuel flow from dead lift pump.

that's why 12valve cummins with it's mechanical pump are favored by a lot of folks!

 

I have read alot about them. I know it can toast it self if ti does not have fuel, but why would i still be pushing fuel past it and not starting, that is what i dont understand. If it toasted it self then it should not turn to pump correct? When i disconnected the low pressure line when i went to replace the lift pump, some gas dribbled out form the VP44, so i dont think it ran it self completely dry. And i also opened the return line out of it and fuel can out from it there too. This was all when i went to replace the lift pump.

 

If you look at the two most common VP fail codes, P0216 is a timing failure, and the P1688 is an internal controller failure. I'm thinking the 216 is mechanical and the 1688 is electronics. Anyone know for sure?

In a way, you're lucky. Mine died in Grand Junction Colorado last June with just at 200,000 on the ticker. I called Diesel-Dan (FASS guy) and asked if he knew of anyone in that area that done good work. He put me on to a Cummins Dealer/shop that took good care of me. Just for kicks, I called the local Dodge dealer and they wanted $2600+ and I got it done for $1600 at the Cummins dealer, and that included a cracked pump bracket. These guys rebuild their own pumps instead of sending them out. Not cheap, but not bad for being 1200 miles from home. The shop foreman was a really knowledgeable guy and got me out of there in one day. He attributed my FASS pump for the IP lasting as long as it did. I wish I had thought to ask him about the difference in the codes.