cat 3116 engine problems

[picard25]

my truck died on me all of a sudden while going about 40 mph. i limped it to the garage and seemed like it was missing the whole way. before it died the exhaust got really loud and there was a loud air loise but at the same time i had an exhaust leak. exhaust got fixed at the same time as everything else and no more hissing or loud air noise so im assuming it was from that. also when i start my truck in the morning the exhaust was really white for the last little while but its really cold here so i had assumed it was from that but im starting to think differently now. they did several things their including looking for leaks and didnt see any. anyway eventurally my main pump hiue i guess got changed not cheap. the one they got didnt work on the bench, didnt lift fuel. so this was at midnight so they decided to take apart my old one which also didnt work on the bench and cleaned up the lift pump in it and put back together and it starting working on the bench. put it back in truck now starts and runs great. i took it for a ride and got it up to 60 mph no problem. the only weird thing was if i had revs up to where i needed to shift but decided to stop instead i put in neutral and it would sputter and die right away. if i had revs up and stepped on the brake with it in gear and waited for revs to slow down than put in neutral it was fine. worked good for about 2 days smoke in the morning was considerably less. than all of a sudden i had no power. not missing or anything like before but no power at all. revs would be up like crazy but no speed. pull out turbo and get tested its fine. so maybe a weak pump. buy a new one this one works on the bench. put it in and now instead of no power im back to the original problem i had sputtering and seems to be missing. im lost and so is everyone else i bring my truck to. i have all new fuel lines and even bypassed one of the filters. they also put in a new check valve. the dealer i brought my truck to got my truck running and was running really good on idle in the shop and reving it up to. ran really good on ther test drive till they got to sixth gear than it sputtered out on them and now its back to where it was before not running good at all. i really need help. maybe that combustion gases thing or is there a sensor or something?

[picard25]

sorry its a 98 gmc c7500.

[damutt]

picard when you installed your pump did you realign the injectors? if not that is the miss or might be.

[wertman94]

I had a similar problem. Mine would run fine until I had the engine under full load and then would sputter and cut-out. Turned out to be the primary fuel filter (which I did not know it had) was full of water. Drained it and worked fine. I know you said you had bypassed one of the filters, have you checked the fuel tanks for water?