1998.5 Cummins dead petal engine jerking

[Allen Crooks]

My 1999 Dodge 2500 has developed a dead petal at times, I press the petal and it revs then drops. Can I assume it's a TPI ? Help!

 

[BoeingDiesel]

With a 2nd Gen you can't assume anything. A little more info on your truck eg; mods, additions and a little more detail describing the problem will help. BTW, like your avatar.

 

[Allen Crooks]

it has actually been a series of events, first driving down the highway the engine went to idle and when i pulled off the road the petal was dead when i turned off the truck and restarted it was fine for a while, Then it started jerking and around 1500 rpm would act like it was choking out. Now my obd reader won't work I just replaced the TPS and that seems to have cured the dead petal but now there are starting issues! Seems as if Gremlins have invaded my Cummins

 

[Allen Crooks]

and Thank you 13 TFS

 

[BoeingDiesel]

Have you checked all the obvious eg; fuel filters, lift pump activates etc...do you have a fuel pressure gauge?
Thank you for your service. I had a friend, who has now passed, that was a Thud driver 13th TAC.

 

[Allen Crooks]

yes all the obvious have been checked i don't have a pressure gauge someone told me it could be a MAP sensor?

 

[fest3er]

IIRC, in the past in TDR queries, this has been a failing VP44.

But do eliminate other possibilities first.

 

[JR]

MAP sensor will not cause a hard start. What exactly is it doing? Does it start at all? Extended crank times,. not turning over at all, etc. . OBD port not working as in no communication? Gotta have more details.
Also, a fuel pressure gauge is almost mandatory on trucks for both preservation of the VP44 and troubleshooting. If installing a permanent gauge isn't in the cards right now I'd at least source a test gauge. You may even be able to rent one at an auto parts store. IIRC you should have 1/8" NPT port on the top of your fuel filter housing.

 

[Allen Crooks]

obd port wont even power up my card reader or the one at the auto parts store. it seems to be dead Fuses are good so i have no clue there. hard start is extended cranking sometimes but not all the time. Fuel filter has been changed and lines bled. Computer has been reset via disconnecting the negative battery terminals for about an hour then reconnected.

 

[Allen Crooks]

also when i turn the key to on the lift pump comes on for about 2 seconds and if i bump the starter it comes on for about 15-20 seconds and then shuts off from what i am told this is normal operation

 

[DavidC]

 

[JR]

Looks like pin 16 is the power and is fed from fuse #12. Did you test the fuse or just a visual? If there are other items on that circuit that work it's probably fine, but I'd probe that pin for power. If none trace it back to the fuse panel.

also when i turn the key to on the lift pump comes on for about 2 seconds and if i bump the starter it comes on for about 15-20 seconds and then shuts off from what i am told this is normal operation

Yes that is normal operation. When are the hard starts? When hot? Cold? Or both.

 

[Allen Crooks]

moreso when cold but can happen anytime

 

[JR]

Hard start after a long sit could be air introduced into your fuel lines. Only way to verify is with a gauge, if pressure comes up immediately when lift pump is activated your good. If gauge doesn't come up right away and the hard start is there you've got air in your system. That would be the first thing I would verify, along with fuel pressure while running.