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First I will start with the back story. I went out to shovel one evening and moved my truck to the street. After I got done shoveling I went to move it back to the driveway when it would crank but not fire. I had it towed to my mechanic. He changed the fuel filter and it ran. On the way home I noticed the tachometer would be jumpy, dropping to 0 then up to engine speed and then to 0 and so on, but there was no pattern to it. Then the engine would hiccup like it was running out of fuel. But only for a moment, then it would run normal. It did this all the way home, being sporadic in the tach and engine hiccup no patterns. So I got home and later went out to go somewhere and it would crank but no fire. hours later I tried it again and it started. I drove it around for like 20 mins added fresh fuel came home turned it off. I immediately tried to start it again....crank no fire. Let it sit for a few hours and it will start. Same tach and hiccups, check engine light is on. Please can someone tell me what this might be. I am fearing the worst if you know what I mean.
 

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I would say, put it on a scan tool and have it checked for codes. My guess would be Cam or crank position sensor. I'm not sure if your year has both or 1 or the other, but that seems like it would mess with your tach signal.
Sean
 

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mwilliams said:
First I will start with the back story. I went out to shovel one evening and moved my truck to the street. After I got done shoveling I went to move it back to the driveway when it would crank but not fire. I had it towed to my mechanic. He changed the fuel filter and it ran. On the way home I noticed the tachometer would be jumpy, dropping to 0 then up to engine speed and then to 0 and so on, but there was no pattern to it. Then the engine would hiccup like it was running out of fuel. But only for a moment, then it would run normal. It did this all the way home, being sporadic in the tach and engine hiccup no patterns. So I got home and later went out to go somewhere and it would crank but no fire. hours later I tried it again and it started. I drove it around for like 20 mins added fresh fuel came home turned it off. I immediately tried to start it again....crank no fire. Let it sit for a few hours and it will start. Same tach and hiccups, check engine light is on. Please can someone tell me what this might be. I am fearing the worst if you know what I mean.
I spent several years working at a Dodge dealership and seen lots of 'em with the same attitude as yours. Chances are it is what you fear. If you have a code scanner check to see what the fault is. If it is cam sensor or Injection pump, it means the same thing: injection pump (the cam sensor is an integral part of the injection pump). The really bad thing about those cummins is the supply pump. They can go bad and your truck will continue to run normally because the injection pump creates enough vaccuum in the fuel line to feed the engine. Problem is the volume is insufficient to keep the injection pump cool and it will destroy the pump. If you do end up putting another injection pump on, I would highly recommend putting on a high quality aftermarket supply pump on at the same time. Preferably one with a higher gph than stock (sorry don't recall stock rating), and a supply pressure of 16-20 psi and put a permanent mounted gauge in the cab that monitors pressure between the supply pump and injection pump. Most of the injection pump failures I've seen were caused by a faulty supply pump. The only other "common" failure I can recall that might cause your issues would be a crank sensor. If memory serves, Its in the side of the block, kinda behind the starter (drivers side). One more thing, if you test your supply pump, do the volume test as they will most of the time pass the pressure test, but fail terribly in the volume department. Pressure is important, but volume is just as, if not more important to the well being of the injection pump. Hope this helps, good luck.
 

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Actually small correction...

The cam sensor is located behind and below the injection pump and the crank sensor is intergrated to the VP44... My trucks one of these style pumps too...


(Number #22) Cam sensor...

Early trucks had a crank sensor back by the starter but it was re-design into the VP44...

Here is the information on doing volume testing and the MINIMUM pressure required...
http://mopar.mopar1973man.com/2002%20Dodge/Tips%20&%20Tricks/lift%20pump/lift%20pump.htm

Here is the documents on how to replace the VP44...
http://mopar.mopar1973man.com/2002%20Dodge/Tips%20&%20Tricks/VP44%20replacement/vp44%20replacement.htm
 

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The original post was about a 98.5 so it should have the crank sensor back by the starter.
Sean
 

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sstockton said:
The original post was about a 98.5 so it should have the crank sensor back by the starter.
Sean
:damnit I'm busted... LOL
 
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