Another Diesel Starting Thread

[Ilikeurtractor]

Actually I didn't answer your question correctly the first time. The initial diagnosis was low compression and upon disassembly of the engine I discovered the stuck rings. I think it was carbon build-up in the ring grooves that were holding the rings from expanding. By that point I already had new rings so I replaced them. I suspect if I would have cleaned the grooves I could have re-used the rings and it would have ran as they did spring apart once freed from the carbon/gum or whatever one wants to call it. The engine only had around 1200 hours on it. I think the root cause was operating the engine under low loads for extended periods of time but that is just a hunch. As I read the original post it reminded me of similar symptoms of low compression. Of course the easy stuff needs to be checked first as in this case but it needs to be kept on the back burner that it may be something more sinister.

 

[buickanddeere]

Actually I didn't answer your question correctly the first time. The initial diagnosis was low compression and upon disassembly of the engine I discovered the stuck rings. I think it was carbon build-up in the ring grooves that were holding the rings from expanding. By that point I already had new rings so I replaced them. I suspect if I would have cleaned the grooves I could have re-used the rings and it would have ran as they did spring apart once freed from the carbon/gum or whatever one wants to call it. The engine only had around 1200 hours on it. I think the root cause was operating the engine under low loads for extended periods of time but that is just a hunch. As I read the original post it reminded me of similar symptoms of low compression. Of course the easy stuff needs to be checked first as in this case but it needs to be kept on the back burner that it may be something more sinister.

Ah , I understand now. Sounds entirely reasonable and makes sense.

 

[Ilikeurtractor]

Not to "rock-the-boat" on the bleeding injector lines theory, but in my experience I have never had to crack the lines at the injectors to get the air out from the injector pump to the injectors. I realize this was the apparent fix here, but if you look at how these injector pumps work there is essentially a check valve on the discharge side of the pump as it enters the injector line. If that is working correctly (and maybe that is the problem here), air will be forced through the line as new fuel gets pumps into the line. It is imperative there is no air in the line going to the pump, but once fuel is there the pump *will* pump it somewhere even with air also in the discharge line. What always seemed odd to me though was how an air pocket on the top of the injector line will come out and go down into the injector since it should stay at the high point but it does. I would be willing to shoot a video showing an empty injector line installed on the pump, tightening it up, and only cranking the engine until it starts and runs fine. I've done it multiple times as I'm sure others here have also. Again, not trying to start battles, just reporting what I have seen to help the general understanding and what one can expect.