After reading a lot of advice on this and other forums, I decided that I needed to buy a fuel pressure gauge. Going on recommendations I’ve received, I ordered an inexpensive Westach gauge. When it arrived, I had a local garage install it. After they finished, I got in to drive the truck back home, a distance of 25 miles. About 7 miles out, the gauge went to zero. I pulled off, shut the engine off, and thought about it a bit. I started the engine back up and the gauge went back to around 11psi idle. It worked all the way home. The next day, when I started it up, the gauge was zero and stayed there. I called up the garage, and they said to bring it in Friday. I called up Geno’s Garage and they said to have the mechanic check all the wiring. OK, I said, and headed off to a town about 50 miles north for some necessary grocery shopping. The gauge read zero all the way up and back, but the engine felt like it normally did. Geno’s Garage got back to me and said that the lift pump itself might be bad. I didn’t think the truck would run without the lift pump running. I took the truck into the garage on Friday. The first thing they did was to put a mechanical fuel pressure gauge to check. Damn, the lift pump wasn’t working at all, so I had to have them replace it with just the standard one. Small town. The garage didn’t know if the lift pump not working would have damaged the fuel pump or not. The diesel fuel tank was from full to 3/4 up and back. I’m content to drive along the winding two lane road around 55mph or so, going through two small towns on the way. I probably drove a distance of 170 miles with the fuel pressure gauge reading zero. Is there a way to test the fuel pump to ascertain if it was damaged or not? I realize that going without the lift pump certainly wasn’t good for it, but our normal camping is often in rather remote areas, far from cell phone towers or anything else. Are there any thoughts out there to estimate the chances that the fuel pump was damaged? Thanks for any and all answers.

After reading a lot of advice on this and other forums, I decided that I needed to buy a fuel pressure gauge. Going on recommendations I’ve received, I ordered an inexpensive Westach gauge. When it arrived, I had a local garage install it. After they finished, I got in to drive the truck back home, a distance of 25 miles. About 7 miles out, the gauge went to zero. I pulled off, shut the engine off, and thought about it a bit. I started the engine back up and the gauge went back to around 11psi idle. It worked all the way home. The next day, when I started it up, the gauge was zero and stayed there. I called up the garage, and they said to bring it in Friday. I called up Geno’s Garage and they said to have the mechanic check all the wiring. OK, I said, and headed off to a town about 50 miles north for some necessary grocery shopping. The gauge read zero all the way up and back, but the engine felt like it normally did. Geno’s Garage got back to me and said that the lift pump itself might be bad. I didn’t think the truck would run without the lift pump running. I took the truck into the garage on Friday. The first thing they did was to put a mechanical fuel pressure gauge to check. Damn, the lift pump wasn’t working at all, so I had to have them replace it with just the standard one. Small town. The garage didn’t know if the lift pump not working would have damaged the fuel pump or not. The diesel fuel tank was from full to 3/4 up and back. I’m content to drive along the winding two lane road around 55mph or so, going through two small towns on the way. I probably drove a distance of 170 miles with the fuel pressure gauge reading zero. Is there a way to test the fuel pump to ascertain if it was damaged or not? I realize that going without the lift pump certainly wasn’t good for it, but our normal camping is often in rather remote areas, far from cell phone towers or anything else. Are there any thoughts out there to estimate the chances that the fuel pump was damaged? Thanks for any and all answers.

A lot depends now on how old the VP44 is. If it is the original 1999 VP44 that came on the truck the chances are good the diaphragm is damaged. I would bet that the pump didn't just happen to go out the day you had the pressure gauge put into the truck. Yes the VP44 will pull fuel without the lift pump as long as the line is tight and full of fuel. Once you get air in the line the VP44 won't pull fuel any longer. If the diaphragm is damaged, the truck could become hard to start. The pump may last a long time or die tomorrow, no way of knowing. The fuel pressure needs to be above 15 at any throttle setting to provide proper cooling to the VP44 electronics. I was into Cummins on April 1 talking to a Cummins mechanic and the subject of fuel pressure came up. He flat out told me the pressure to a VP44 needs to be between 17 and 24 at all times period end of story. Good luck.

Well at this point I would drive it any farther till you get a fuel system install... (AirDog, Raptor, FASS, or Walbro)... I'm starting to suggest a minimum pressure of 14 PSI to aid in keeping the pump cool and lubed. So I would start with getting a fuel system... Yes its possible to run a VP44 without lift pump. But you got to remember the only lubrication and cooling the VP44 get is the fuel so if there isn't enough fuel pressure it like running a engine without oil pressure it will do it but for how long only the big man above knows! Then check for error codes... After all this I would dump in a shot of 2 cycle oil to help lube up the pump (VP44)... Then all you can do is...

Well at this point I would drive it any farther till you get a fuel system install... (AirDog, Raptor, FASS, or Walbro)... I'm starting to suggest a minimum pressure of 14 PSI to aid in keeping the pump cool and lubed. So I would start with getting a fuel system... Yes its possible to run a VP44 without lift pump. But you got to remember the only lubrication and cooling the VP44 get is the fuel so if there isn't enough fuel pressure it like running a engine without oil pressure it will do it but for how long only the big man above knows! Then check for error codes... After all this I would dump in a shot of 2 cycle oil to help lube up the pump (VP44)... Then all you can do is...

- yeah what that guy said (ha !) Once you get the airdog/fass in -> and sure your FP remains above 14/15 ..... then drive it 50-100 miles. Then take to autozone etc and have the codes scanned and see if anything comes up about not being able to advance the timing (P0263 ?) maybe from memory. Michael has the codes here somewhere. If you need a new one - ask the vendors here - I know jkidd does a good combo deal good luck

Thanks to both of you guys for the prompt reply. My new lift pump does give a pressure of 15psi at idle, and 11-14psi at speed. Yes, my fuel pump is the one that came with our truck. I would admire to replace the whole fuel system now to give me peace of mind, as we do have places to go and our little fifth wheel to haul around. Insufficient funds dictate another course, however. It sounds like our fuel pump likely won't last much longer. That's the answer I was expecting, but I thought I'd check to make sure. Not driving the truck is not an option, so I guess I'll deal with the fuel pump when it goes. Appreciate the time you guys took to answer.

P0216 I think is the code - not what I said before Mopars new webiste - all the links are broken - haha - proves he can't fix EVERYTHING *joke* Yeah - I know how funds go ...................... maybe try craiglist etc - you never know - also keep an eye on the cummins and mopar1973man threads - sometimes people part out wrecked trucks where the vp44 has only 30k miles or slightly more rarely an airdog etc Unless you start getting really crappy mileage and hard starts - not sure what else damage you could do - so probably could just run the one you have into the ground so to speak - but someone that knows more than me will be able to answer more 'definatively'. I had to replace mine as was only getting 13-15MPG interstate and was hard to start etc

I just barely filled my tank again, as the price of diesel appears to be on its way up here. I get the same mpg as I have for years - 19-20mpg solo. I haven't towed our trailer since last fall, but when we towed last year the fuel mileage was 10-12mpg, same as always. The trailer is a 26' fifth wheel and weighs around 11,000. The truck isn't hard starting at all.

Sound like you got lucky so far... Still you need to check error codes and get a fuel system installed. Oh yeah NO FASS DDRP they are worthless.

Sound like you got lucky so far... Still you need to check error codes and get a fuel system installed. Oh yeah NO FASS DDRP they are worthless.

YES I AGREE WITH MOPAR..DDRP..EQUALS NOT GOOD ENOUGH..just to a stock truck the airdog and fass systems are night and day differences.

I discovered a bad LP once when I changed my filter and it wouldnt prime up, finally removed the line and bumped the starter, pump ran fine but not a single drop of fuel. I have no idea how long because I didn't have a gauge but I ended up trading trucks and that VP is still running today. At least another 40,000 mi., You just never know when.