I have a 96 cummins 12v and the problem is it misses a little you can hear it popping or putting from the exhaust. It has new lift pump and injectors. The truck runs good and if driving it you cant really tell its missing. When standing outside the truck you can hear it. I dont know what else to look at. Any help would be greatly appreciated. Also forgot to say it only has 86,000 miles.

 

laser thermometer on the exhaust manifold will tell you wich cylinder is missing, if the injectors are new try swapping them and see if the miss follows , if it doesnt verify the fuel line is not restricted ot kinked in any way .. if that isnt a issue ............

might be a pump issue

good luck
scott

 

I was told by a diesel mechanic it could be a fuel delivery valve what you think

 

a dv kind of unlikely but could make it miss i guess check what cylinder is missing and then pull that delivery valve, when was the last time the valves were adjusted and how bad is it maybe the timing jumped a lil?

 

They were never adjusted or replaced....the timing Is advanced to 16.5

 

I had a buddy who had a truck that the previous owner had a pump put on and for some reason there was a copper washer in the number 1 delivery valve socket. I pulled it out and reinstalled the valve. Ran perfect i suspect the extra space from washer allowed more fuel to be pushed out of injector causing a hard hit not a miss.

 

I been told its doubtful its the pump since it only has 86000 on it and the p7100 pumps are the best there is...it also sat for awhile too but would the lift pump cause a miss

 

i really doubt that it supplies the whole pump meaning every dv but now that we know your timing was advanced that means that one ove the dvs was opened up and maybe it is a washer or lack there of a washer perhaps im sure someone with a similar problem will chime in!!

 

What do you mean by one of the dv's were opened up

 

to time the pump you have to remove a delivery valve and screw in a the gauge