Engine/Transmission (1994 - 1998) nocking sound from fuel pump and barely running

[78cummins-wagon]

found solution to the 1994 with the bad trans. bought a 1995 with 71000 miles for $600. the truck ran fine for the first few days, then it stalled at the intersection (automatic trans) it would not start back up, untill i pushed my foot about half way on the gas pettle, and as soon as i let off it would dye again. remind you the whole time its making a loud tick/knock. the gas pettle was verry hard to push, then about half way down it would get easy again. almost like it was binding up. i pumped it a few times and it started right up like nothing happened. it ran fine for 2 more days untill it did it again today. i dont know what it is and i would like to find out. i bought 2 cummins's for under 2k and they both have problems now!!!!! any help would be appriciated#@$%!

 

[BigPapa]

Don't give up. Realize when you get those "great deals" your probably buying something with problems that someone has given up on. Very rarely do you get more than you pay for.



Have you changed the fuel filter? Anything causing restrictions after the lift pump will cause it to knock. Also check the pre-filter. It's right there at the lift pump and can get clogged.



Have you checked the shut-off solenoid? Check the same things you were advised on with the other truck. Make sure you have full travel from the solenoid. Also, make sure the woodruff key is still on the shaft that the solenoid turns. It's very small and easily lost.



Check the overflow valve. Someone could have gone into it and put a stiffer spring in. I'd suggest taking it apart and if you question if it's the right spring, take the one off the other truck and compare. Check the length of the spring. It should be 1/2" long. If not, stretch it out. This will get you by until you can get another one but it will not last that long.



If all this checks out, then replace the lift pump.



Scott

 

[Joe G.]

found solution to the 1994 with the bad trans. bought a 1995 with 71000 miles for $600. the truck ran fine for the first few days, then it stalled at the intersection (automatic trans) it would not start back up, untill i pushed my foot about half way on the gas pettle, and as soon as i let off it would dye again. remind you the whole time its making a loud tick/knock. the gas pettle was verry hard to push, then about half way down it would get easy again. almost like it was binding up. i pumped it a few times and it started right up like nothing happened. it ran fine for 2 more days untill it did it again today. i dont know what it is and i would like to find out. i bought 2 cummins's for under 2k and they both have problems now!!!!! any help would be appriciated#@$%!

Don't just throw parts at it.



Email me at -- email address removed -- for my write up on the 12 valve fuel supply system, how it works and how to fix it.

 

[JGK]

Have you isolated the tick sound? Is it the P7100 or somewhere else?



Late last summer mine started acting up that way - dying at a stop then starting right up and running OK until one day it died and would not stay running unless I worked the throttle all the time. Not exactly as yours but kinda similar. Mine didn't have the knock, though.



I discovered a bent governor spring stud on careful inspection down the cam plate hole. Turns out my rack stop pin had broken and jammed up momentarily in the governor case and bent the spring stud. Can't bend them back. It took out a c-clip on one of the governor pivot shafts too.



A week later and $1300+ "lighter" I was back on the road.



Pull the AFC and cam plate and carefully inspect the governor assembly with a bright flashlight. Have someone bar the engine over slowly with a ratchet on the alternator bolt. If you suspect something is missing or wrong, you can fish around the bottom of the governor housing with a magnet through the back cover where you access the governor lever adjustment screw. I found my broken pin, c-clip and bent washer doing that.



-Jay