LLY crank no start

[JonB]

Alright guys ill keep this as short but detailed as I can:

2005 topkick, LLY with allison tranny. Long story short, truck had gasoline put in it and catostrophic engine failure, swapped a junkyard engine in and flushed tank and lines. Didnt have any issues for 2 months, DROVE back into the shop running very rough, engine speed sensor codes and mutiple misfire codes. Drained fuel/water seperator and got about a 50/50 mix of water and diesel. Drained entire fuel system to include fuel rails, refilled and primed with clean fuel and new fuel filter. Couldnt build anything over 1300 PSI FRP. Tested fuel return on injectors on the right bank, found one returning about 4-5 times the max spec for fuel return. Replaced injector, now FRP is buidling to desired around 58-5900 PSI (up to 11,000 with regulator unplugged) during cranking but still won't start. Cam and crank signal both present, voltage is only dropping to 11.5 while cranking, no codes, no smoke. Only thing I have been able to figure out is calculate fuel rate during cranking jumps to 65 mm3, but I can't see balance rates since it doesnt start. I know that fuel rate is out of spec, but not sure what it means or where to go from here.

 

[2004LB7]

65mm3 doesn't sound off for cranking

Water can do awful things to injectors. Might be worth pulling glow plugs and seeing if you are getting any fuel spray. Possible you got a bunch of rusted pintles and nozzles. If that is the case, new injectors are in order

But multiple misfire and speed codes does make me think you could have lost a cam or crank sensor. You said you have signals for them. What about cam to crank sync or missed pulses? Did you spin the balancer or snap the crank?

 

[JonB]

65mm3 doesn't sound off for cranking

Water can do awful things to injectors. Might be worth pulling glow plugs and seeing if you are getting any fuel spray. Possible you got a bunch of rusted pintles and nozzles. If that is the case, new injectors are in order

But multiple misfire and speed codes does make me think you could have lost a cam or crank sensor. You said you have signals for them. What about cam to crank sync or missed pulses? Did you spin the balancer or snap the crank?

I don't have a clue what fuel rate should be, I am using an Autel scanner and parameters that the scanner thinks are out of spec light up red, its been pretty accurate with other vehicles so I was assuming that it was in this instance as well.

So a little more info on the the "long story short." When the truck came in, I kinda fiddled around with it for a couple days before bringing it in the shop for diag. Each time I ran the engine, I cleared whatever codes came active that ignition cycle As for the misfire codes, they would be different cylinders on almost every key cycle, sometimes all on one bank, sometimes a couple on each. never consistent and alternating with key cycles, IMO consistent with a misfire being caused by severely contaminated fuel. Speed sensor code would always come back after engine running for 5-10 minutes. I can't remember the number of the code, but it was a generic code that said it could be the cam sensor or vehicle speed sensor. Code was also in the TCM so I'm thinking vehicle speed sensor, but not sure.

As for the missed pulses, every parameter I have on my scanner for a pulse has said 0 pulses missed. Doesent seem very likely to me that the crank or balancer is and issue as it didn't die while running. Crank/no start didnt hapen until after draining the fuel system.

 

[JonB]

I want to add that it was only a matter of about 3-4 hours between engine running, completely draining fuel system and attempting to restart.

 

[2004LB7]

Well, just a piece of information for you, if the engine looses a cam sensor while the engine is running, it will continue to run and drive. But will not restart if you shut it off. If it looses a crank sensor, it will die right there. Also, if the cam and crank are out of sink, it may not start depending on how far off it is.

When the engine is running rough, that is really hard on the balancer and puts a ton of stress on the balancer pin and if that pin is already weakened, it can shear and the balancer can shift on the crank and throw off the timing.

With your descriptions of the symptoms, there is going to be a number if thinks you're going to need to inspect and verify. The idea that it was running shortly before isn't a great diagnosis tool as the engine doesn't run now. Obviously something is not correct

I'd verify fuel to the cylinders first. Sometimes you can see smoke from the exhaust. Sometimes you need to pull the glow plugs. And occasionally you need to pull the injectors and figure out hooking them up to fuel and seeing if they spray. Or you can just send them all out for inspection