Engine/Transmission (1998.5 - 2002) New vp44 new Fass DDRP and hard start

[DDouglas]

I have a 1999 CTD 2500 I just put a new Fass DDRP and a new injection pump on and at first it would fire right up perfect. Now a few days later it is getting hard to start, The only thing that I noticed that I didnt before is when I turn the key on to get the preprime the fuel pressure goes up to 18psi and then when the pump stops right before you turn it on the pressure drops instantly then as you bump the starter the pressure goes back to 18psi then it stays there. but is hard to start it will crank forever and finally starts and runs fine . once it preprimes should it hold the pressure right before starting, or it that common to drop the pressure? and like I said the fuel pressure goes instant up then instant down then up again at crank. It seemed to me that on my other trucks they held the pressure. and I have looked it all over for leaks but nothing.

 

[damar]

I have a 98. 5 with 180,000 miles on original vp. Have had a Fass 150 on for about 76,000 miles. Mine always pumps to 16 lbs, drops to zero and then when I turn key to start jumps back to 16 lbs and stays there. I truck turns over about 3 times before it starts. I starts just as quick or quicker than my Ford Crown Vic 4. 6L V-8. I would guess that you have something other than the Fass causing the problem. Maybe someone else will drop in and give you some ideas. I just have never had any problems with my CTD.

 

[Joe Mc]

Gage is not mechanical, when you crank there shouldn't be voltage to it until you release the key from start to run position.

Might be sucking air somewhere.

 

[Snowfan]

Sounds like a common problem. The VP44 does not tolerate high pressures at start-which happens when the engine is warmed up with the DDRP. The DDRP needs to be rewired into the 'run' circuit, instead of the 'start run' circuit so that it only pumps when the engine is running. To test this theory, unplug the DDRP and see if the engine starts first crank (it will). Shut her down quick so as not to fry the 44.

 

[BDaugherty]

When it does start, does it run rough at first or does it idle smooth immediatly? If it's smooth right away, it's the electronics in your VP44. I had the same exact problem with a VP44 I put on a couple months ago. Another VP (under warranty) solved the hard start issue 100%.

 

[DDouglas]

Well I found the problem, this truck has the old style fuel filter, the one that the bottom cup comes off , I pulled the filter out and the middle sized o-ring had blown out, so I replaced the o-ring and it lasted about a day and blew out again so I pulled an extra 2001 filter housing off my shelf and replaced the old style filter set up with a later model one and it cured the problem. the truck starts right up on the first crank.