Engine/Transmission (1998.5 - 2002) New vp-44, LP occasional hard start

[sheamc]

A couple of months ago replaced LP-VP-injectors, buttoned it all up and it started right up after bleeding the lines. Now, if the engine has worked hard and built up some heat when I go to start it up it stumbles for a few seconds. Even then not all the time While it runs, its great. Fuel pressure stays at 14-15 psi all the time. If this occured all the time I would almost feel better. Everything seems OK. Haven't found any leaks, doesn't mean there isn't one though. Any help would be great. Also, no codes. Thanks for the help.



Shea

 

[BoeingDiesel]

Sounds identical to what my 99' started doing a couple days ago. I've checked all connections, new filters, and swapped the ADS relay as per John Landrys' suggestion, but it still stumbles a little on startup (after the motor is warmed up). I'm going to replace the starter this coming week with a Nippon Denso remanf. unit and we'll see if that's the problem.



99' 2500 SLT QC 2WD AT Airdog 100 Isspro Gauges DTT Filter PDR HX35TC 268k miles

2006' H. O. 6spd. 3500 QC 4x4 SLT.

 

[Mishkaya]

A couple of months ago replaced LP-VP-injectors, buttoned it all up and it started right up after bleeding the lines. Now, if the engine has worked hard and built up some heat when I go to start it up it stumbles for a few seconds. Even then not all the time While it runs, its great. Fuel pressure stays at 14-15 psi all the time. If this occured all the time I would almost feel better. Everything seems OK. Haven't found any leaks, doesn't mean there isn't one though. Any help would be great. Also, no codes. Thanks for the help.



Shea

No codes is always a good thing. Did you by chance change the crank position sensor when you replaced the injection pump? It's recommended to do so from what I've been told as it is easy access then, much more difficult otherwise. I'm a bit leery though because when I had that issue on my '02 it ended up being the electronics on the VP44 that had gone bad. I was getting a code 0216 after a while though.

Good luck

mishkaya

 

[AllianceDiesel]

another common place to look is the connector tube o-rings, they will cause the same problems you described, hard start when cold regular starting when warm. I have replaced many and found usually all are flat or are cracked.