We were going down the road when the perfectly running cummins stopped.
It is 100 percent stock and was a service truck for years.. Truck has set for two year until my cousin bought it 3 weeks ago.

Will not start at all.. not even a thump put of a cylinder or two..

The truck has fuel.. I put a new injection pump oto be sure.. timing is 100% correct.. the motor will run on ether.
But will not even cough with just fuel..
the only thing that makes since is compression.. but to loose all 6 cylinders at once?

Any ideas?

 

maybe bad injectors?

 

i have pulled he injectors out of the head and they fire.. that ruled out the injection pump and injectors for me.. when we crank the motor we get little bobbles coming up the head bolt that holds down the rocker arm block. im working on borrowing a compression tester adapter for the injection port.. i hope i find the issue soon

 

well to me that sounds like a head gasket failure. pull the head off and give it a look over, you can get a top end gasket set for around 150$ and while your there you should put head studs in it, the hungry diesel has A1 head studs that fit without machining the rocker arm pedestal, but you will have to clearance the valve covers

 

If she was running and just stopped highly unlikely that was a result of a head gasket.
Back to fuel or timing.
How good a flow are you seeing from the injection line or injectors?
Is there any smoke from the exhaust while cranking?

 

Its not injectors or head gasket.

Will she not turn over or just won't fire once cranking?

 

timing is correct.. it has been verified like 5 times... the pump is in time.. we have advanced it and retrarted it.. the cam is in time.. i have a vissual on the cam, and injecion pump keys that did not get sheared.. on top dead center the correct vavles are up and 180 rotation the correct vavles are up. timing is not the issue..

motor runs great on ether.. i can let it set there and idel by adjusting the amount of ether im spraying..

the lift pump is supplying plenty of fuel.. i even tryed to run with gravity feeding the injection pump...

the injection pump it working fine.. it sprays through all 6 injectors..

if you crack the lines the fuel has enough pressure to spray the hood.. there is no bubbles in the fuel, so no air in fuel..

i seriously doubt that head gasket lost enough compression to not run in all 6 cyc...

im looking for alternate ideas.. not the ones ive already checked and crossed off the list..

crazy thought i had was if some how all 6 exhaust or intake valves got messed up and now dont seal.. seals enough for ether to fire but not diesel...


btw if i bring the motor to 2500 RPM with ether... and pull the throttle on the injection pump.. there is 0% change.. i find that a little odd.. i would think at that rpm and having the ether ignighting the diesel would do something.. any thoughts?

Thanks,

Scott Morgan

 

Back to the original problem. Please run us through what happened
This just stopped while running down the road? Sudden stop or slowly die?
After that it would not fire or attempt to fire? No smoke from the exhaust?
You then fitted a new Injection pump and still no sign of smoke or attempt to fire?
Did you manage to get a compression test?

 

ok so we verifed last night we have compression. im getting 400 psi on lowest cycl.. it should be firing.. this also proves timing... i hooked a lift pump straight to the injection pump.. pump out of a nice clean diesel soars.. my next step is to take off the exhaust manifold to see if we are getting any un burnt fuel out of it.. any other ideas?

only thing i dont know for sure is if fuel is getting into the cyl.. im hoping removing the manifold shows me some un burnt fuel, so i can be sure fuel is getting sprayed.. the injectos are firing when out of the cyl, but when they are in the cyl there is 400psi fighting the other way, so it may be making the differance..

 

Blackduck,

The truck just quit.. beings its is a old noisey truck i didnt even hear the motor quit.. my cousin who was driving said "hey my motor just quit!".. so if it sputtered, it didnt sputter long..

trying to start it..
it does not smoke, or even thump at alll... the motor is spinning good when cranking it, so nothing is locked up.. i have tryed to start it on ether.. it will fire, and i can keep it idealing or running at 2000 RPM depending how much ether i spray.. when i grab the trottle, while running on ether, it doesnt make any differnce.. i would think if it was spraying diesel into the cyl the noise, or even rpm would change..

we have by passed the whole supply system to the ijection pump..
we have replaced the injection pump...
we put the old IP back on and removed the fss so we dont have to worrie about that..

they only thing i dont know is if for some reason the injecters are not spraying while they are in the cyl..