Engine/Transmission (1998.5 - 2002) Engine miss fire

[RGagnebin]

I have 98 24v that is miss firing on the front three cylinders we put a bypass box from cummins on the injector pump to take out the other components thereby just having the injector pump and injectors in the system and it runs fine!!!

With the truck in the normal configuration at idle and miss firing, using an infrared temp sensor the exhaust port temps are around 260 on the back three and 140 on the front three. . This missing firing comes and goes. .



Has anybody had this type of problem????

 

[obert]

Is this the random miss that goes away with a slight load? Like AC pump or loading hydraulic pump with brakes or steering?

 

[RGagnebin]

It might. . not sure if it for sure goes away. When we we're testing the engine by killing a cylinder with our scanner, it would be missing out then we would kill a cylinder bring it back then the miss would clean up for maybe 30 seconds then be back. . it is random.

 

[CRead]

This might be a dumb question any codes? And if it runs fine when on the cummins box I don't think it would be the pump or injectors. Does this change with engine temp? Im saying this is I have seen engines run great cold and when they get hot they miss and vice verse. Because of ecm location the ecm engine heat will effect it. When it misses have you cracked open the injector lines one by one to check for rpm change? Sounds like you have access to cummins stuff I would try to find out what controls the pump for what injectors get fuel. I didn't know the vp44 could check each injector? What is the truck doing when this happens? Good luck keep us informed.

 

[RGagnebin]

The temp does not seem to have anything to do with it, as far as cracking the injectors it does have an affect because my front three are working but not as much as the back three. I know this does not make any since but thats the way it is, its like I'm loosing half my computer or part of the half. 1,2 and 3 produce combustion but at a lesser rate than that of 4,5 and 6 untill you put on the cummins test box then all is fine.

 

[Turbo Tim 1]

Early on when I owned my truck I would get a really bad skip or lope, infact one time when I pulled into the dealer the mechanic said, "Got quite a hitch in your giddy-up" we hooked up the box and everything was fine, went back to normal and everything was fine. I sarted loping again so I went to the dealer and the same thing happened, we could never get it to repeat on the box. A short while later it stopped happening and never happened again till more recently (150,000 miles later) Now when it starts doing it I have found that a good dosage of additives helps out.



Now I know this doesn't solve your problem but realize that maybe the problem solves itself for the time its on the box because you have to shut the engine down to put the box on so maybe it could be the injection pump??

 

[obert]

I never had it untill the VP was replaced in late '01. I've been told "its just a quirk of the pump". Not shure I'm buyin' that.....