Hi there, I have a 95 3500 with a 5spd 210xxx n the clock. The truck has a pretty bad miss to it. I replaced all 6 injectors,new lift pump, new ofv, and injector lines. I crack all the lines at the injector and the #3 injector doesn't change tone. The local mechanic thought that it was maybe a bent valve because it you can hear it pop back through the intake. Could the injector pump be causing the pop thought the intake? I'm kind of new to cummins and any help would be apprecitated. Thank you in advance.

 

have you deleted your fuel heater? you might be sucking air into the system. switch the #3 injector for one you know is working right. see if the problem follows #3's injector or if it is something else.

 

Yes I did delEte the fuel heater. I will swap injectors tomorrow and keep updated. Thank you very much for your input. I've been fighting this truck for 9 months. Trying not to get an injector pump.

 

do a leak down test on the cylinder your mechanic thinks has a bent valve guessing cost lots of money

 

Pull the valve covers off and roll the motor over and watch the valves to see if ones def shorter or moving less than the others

 

Would a compression test suffice? I pulled the valve covers off and turned it over and they all move the same distance, no real indication of anything wrong with the valve train. The valve lash was good as well. I'm starting to lean towards delivery valves of the whole pump. Is there a tester that goes up high enough to test the pressure at the pump?

 

I hope you can figure this out cause mine does the same as yours. I have done all the things you have done and still has a miss. Truck runs strong but the miss bugs the crap out of me. I got the truck bout 6 months ago and it didn't do it then and can't really remember when it started. Mine seems to miss on #4 I marked the barrell and moved it a little both ways no help either way so I put it back where I started. The pump on my truck was supposed to have been rebuilt not long before I got it so you would think it would be OK. I did have the timing advanced shortly after I got the truck. Hope one of us can get it figured out.

 

hold the #3 line with 2 fingers while its running and see if you can feel the fuel pulse thru the line. also like said before swap the #3 injector with another one and see if the problem moves or not. lastly yes a compression test would work you want to see +350 psi

 

Okay, update. Ran the compression test. 360 psi. Swapped the injector's. No change. Decided to crack the lines at the pump and discovered that #'s 2 and 3 are putting out almost no pressure at all. And no tone change in the motor. I pretty sure it's the pump considering it had probably never been changed. Sound reasonable? Any other suggestions on tst to run?

 

if it was at my shop at this point we would bench test the pump