I just put my tank back in and replaced the remaining rubber line with AN fittings and stainless steel hose. I go to fire it up and it turns over for about 10 seconds then fires. I have been driving for a day now and every time I start it same thing. There is 15 PSI at the test port on the VP44 when I start it, so clogged filters aren't the issue. Once the truck starts, it is fine no bad MPG (yet).

I know that this is the first sign of a bad VP44, but the thing was working great when I dropped the tank. I checked for codes and the only code in there is P0463 (fuel sender voltage too low) and I believe that is where I turned on the ignition while the tank was out of the truck. Is there anything I could have done while dropping the tank that could have cause the hard start? Or is it just a coincidence that it went out the same time I dropped the tank?

 

well bob beasty need about 10sec to start now and im highly suspecting my VP44,im waiting for my fass to be installed just to take anyting out of the equation but im pretty sure ill have to get one..
im still looking for leaks that migh let some air in so its hard to start,im thinking about an injector being wounded but its still pull really hard.... i dunno

 

I didn't think about trying the backup pump. I tried it and it does the same thing. Both pumps have different lines so I doubt air would be getting into both.

 

I think you may have air trapped in the system somewhere. Someone here should know how to bleed it properly. I wish I could be more help.

 

I ran a piece of clear tubing and connected it to a check valve and connected that to the test port on the fuel filter and my fuel looked like fizzy Mt. Dew soda. So I knew at that point it was an air leak. Sure enough after taking apart half of the stuff I had just put in, the in-line filter was leaking air around the seals. Torqued them down gorilla tight and now the truck starts and runs fine. I'm glad the VP44 is still good!!!

 

u put light in my days,maybe i got the same problem then...
ill install my fass and check for leaks then

 

I found my leak by taking off the entire line that went from the pump to the fuel tank. Pluged one and and put compressed air in the other. The leak bubbled up and squirted disel out. Fixed the leak and re-installed the line.

 

Mine did that about a year and a half ago, good fuel pressure everything seemed fine. I checked all the fuel filters all were tight, but it seemed like one of them might be leaking a little. I took it off and put a sealer, no not directly on the gasket but just to the outside so it wouldn't touch any fuel. Must have just been that filter because I've changed filters and such since then and never had a problem.

 

Is a VP44 the stock Bosch injector pump or is the VP44 a replacement? I've got 60k on my Cummins and put in a new lift pump at 50k--had to drop the tank because of faulty sending unit anyway so I changed the lift then.

Trying to figure out the different numbers/models for the setup. Hopefully I'll never have to replace the stock injector pump as I just ordered a fuel pressure gauge setup so I can monitor the lifter.

 

The VP44 is the Bosch model number of the injector pump, new or used, it's the same number.