350 diesel engine miss

[Burnie JD350]

HI everyone,
I have read every post on this forum and have not seen my problem mentioned. I,m hoping that one of you diesel fuel system experts have run into it.About 15 years ago I was working on a very steep slope with my 350 diesel loader.I was going up and backdragging down. Suddenly, going uphill, it started to miss. I thought maybe, because of steepness, that water or dirt in fuel tank got into system. So I drained tank, changed filters, and filled with fresh fuel. Still missed. It doesn't miss while increasing engine speed, but no matter what speed you stop at, it misses constantly, both under and not under load. I have not checked further, because I didn't know this forum existed, and I know nothing about diesel systems. It still misses, but has enough power for hard digging. I have been wondering, since reading here about the governor weight retaner, if that might be the problem. I sure wish the internet and this forum had been around 30 years ago. Thanks.

[Lavoy]

Being the cheapest route, I would look at replacing injectors first, then look at the pump. Normally a rotary pump should not pick one hole like that. Not that it is impossible I suppose, but not as likely as an injector bad.
Lavoy

[KenP]

deleted

[Stan Disbrow]

Hi,

Yes, the only way to know is to pull the pump and the injectors and take them to a shop where they can test them. Then, you will know for sure.

Otherwise, it's a crap shoot at best.

later!

Stan

[JWB Contracting]

Another issue beside the actual injection system and pump and be a plugged return line. To check this, remove the return line fitting on top of the injection pump and run it. Worst case senario, this isn't it and you dropped a little bit of diesel on the ground.

We spent many hours a 3020 tractor and even had the injection pump rebuilt only to find that the return line fitting on the pump was faulty.

Doesn't cost any money to further diagnose the problem.

To test the injectors, run the engine and loosen each injection line, one and only one at a time. If unloosening the injection line causes the engine to sputter, then that injector is fine. If no change and if you are getting fuel squirtting at the injector, then the injector is faulty. Try all cylinders, cheaper to replace one injector than all.

Good luck

[CatD8RII]

is this a straight 350 or a B or C? the Bs and Cs have an inline filter in the supply fitting back at the tank, you have to separate the fuel lines and shut off valve to get to it. Im not sure it the straight 350 has one there or not

[Burnie JD350]

Thanks to all for your help. I'll be checking these in the spring.

[mikehutchen]

Probably a leak off bypass line check valve clogged up. It is located on top injector pump.

[DSMason]

My 350 crawler loader had a miss develop very soon after I bought it. I replaced the fuel filters, delivery pump, and injector in the cylinder that was not firing. Turns out it was lack of compression! So now I’m in the process of doing an in-frame rebuild.
Good luck!

[gregjo1948]

In reference to the mentioned check valve at the pump--I had a JD tire tractor with a bad one and it would start, run 15/20 seconds and die. I could let it set a minute and do it again.