Recently i had a bad connection at the PDC it was repaired truck ran fine for several weeks . I dont think this has anything to do with that previous problem.Now noticied that sometimes the truck does not respond when given throttle,and has lost power just crusing aswell.The lift pump is working fine but im still pointing to the Injector pump.When given throttle it seems to almost bog the engine down but does not die or stall completly.No codes are showing ,fuel filter is new and no water in fuel .Added some Diesel conditioner has ran fine the last few days .Any suggestions would like to keep this truck,**** its almost paid for!

 

i would say the injection pump, but with no codes its hard to say. i have heard of them dying slowly and not leaving any codes till the end. if all else fails take it to the dealer, and have them scan it.

 

Try a search on "dead pedal".

Rusty

 

Thanks guys for the info

 

I just went into work and put a new VP on my truck for that very reason. About three times this week there was no pedal response. Twice it set a code, once it didn't. P0216

 

How do you know?

Do you have a fuel pressure guage?

Just because it flows enough to fill up the bowl after a filter change, doesn't mean it is flowing enough to keep the VP cool, happy and lubricated.


phox

 

Phox, these trucks will run sometimes an amazingly long time with a dead lift pump. I've lost count on how many I've checked that have come in for other services that will pull my gauge into a vacuum when started up. True it's hard on the operation of the VP, but it's not a sure sign of death either.

 

Most of the time when a complaint is low power or loss of throttle. It is more than likely a Cummins code 368. Which is injection pump internal timing failure caused by a bad VP44. However, I have seen a number of trucks that had a low side restriction causing the code with pressure still in spec. (Restriction from inlet of lift pump to tank) A good check to do also in this situation is to remove the oultet banjo and line from the fuel filter. Install a pressure gauge at the inlet of lift pump and bump the starter to activate the lift pump. You should see less than 5psi and about 2 quarts of diesel come out. As Jbody said, if you have high restriction, the volume of fuel going to the VP44 timing advance will not be sufficient enough for the timing mechanism to work.

Another good check to make the problem reoccur is to hold the throttle wide open at idle and in neutral for 20-30 seconds. More than likely the code will reappear since the pump is trying to compensate for the RPM by raising timing internally. Usually the truck will spit sputter and smoke white.

 

Look into the problems with the APPS people are haveing. Some have disected and tested them and found they are absolutely the worst "toy" like device DC could have mated to the mighty C. $340 for a APPS beats IP cost! Provided you rule out you fuel issue.