i have posted on the help forum about this nightmare -started with head gasket leak,found fire ring setup causing way expensive gasket,head studs broken three weeks finding some one to get it out,replacing expensive studs with arps,now mechanic gets it put together and says ip and transfer pump out. checked injectors and they all function check pump and 2 and 3 low fuel output. the truck runs rough kinda weird since it didn't run that way when we started this odyssey back in july,last time was fired up. should we check compression b4 getting an ip and transfer pump? this has been a real eye opener i mean where does it end.one place suggested that it wasn't ip that it could be a warped head or some such.the truck is in brownwood texas so we are in deep doody as far as good ctd techs go. should we------
question #1 test for definate ip problem
question#2 run compression test
question #3 symptoms of other problem
alright you gurus out there you have been helpful so far lets get this beast back on the road. thanks

 

what year truck or engine are you working on, what mods were done to it before problems arose,etc....
a compression check is a good start but you will not find a spec anywhere in a Cummins manual, they go by blow by numbers.
If you do a compresion check, which I would before buying any parts, look for consistency between all cylinders, a good rule of thumb is no more than 10% pressure difference between cylinders, especially adjacent ones. Check nozzles as you will have them out to do a compression check. verify timing. a good place to start is around 13-14 degrees, it can be adjusted from there, your engine will run pretty good there if you have stock components in it.
I guess I would like to know how do you know for sure that two cylinders are not getting enough fuel. If you think that is the case, try swapping components such as delivery valves and injectors, just do it one component at a time so if you do come across something you will know what it is,( delivery valve or injector)
are you sure the intake and exhaust valves are set correct. I know you may get a little ****** at me asking this but you do not know how many times the simple thinks can cause major headaches.....
I try to test and eliminate any possible cause before I buy parts, especially on my own vehicles, lol

 

its a 97 and has had fire rings, grooves in the head and block, we put two new gaskets and a new set of rings. previous owner had bigger injectors,bigger turbo, this is supposed to be a newly rebuilt motor only 30k miles,,kinda seems strange to have gone to that extent when the truck only has 176k any way. po also ran propane ,lovely we didn't know that or that the truck had the other mods until we bought it,cuz dealer put it back stock to the naked eye.anyway,,,,the injectors were switched to make sure they were not the problem,pressure was checked at injector side and at pump. somehow it was determined that the transfer pump,lp was not functioning so maybe knocked out or is in the process of killing ip.guy says he straight edged the head and block and not any sign of warp .does this help any?