So currently at work we have a Komatsu PC78MR-6 that had a bad primer pump to the fuel filter that has been replaced and a new fuel filter installed, but yet when I go to crank it over it blows white smoke now like it did before still also it will shake violently and will not stay running for more than two seconds. When I do finally get it running I can’t put it past 1/8 throttle about and if I turn it up or turn it down slightly it dies immediately. My question is, could it be clogged injectors or what else might it be? I used to work on machines and dump trucks back in Wisconsin But I don’t have all the tools I used to in the shop or exactly all the knowledge needed.
Might have an injector stuck open. I’m not familiar with that engine or equipment, but when I have these issues I pull the exhaust manifold off and check which injector is squirting. If it’s common rail I’ve had luck using a cap fitting to block the damaged injector at the rail.
Does fuel run very freely after the fuel filter with line going into a pail. Could be a problem in the tank if not free flow, or in the line or filter. Know of a filter just changed that was plugged again in 2 minutes. Not saying that is your problem, but need to check off simple things before buying expensive things unless your filthy rich. Simon C
Would not have a totally plugged air filter like one I found yesterday? Would not be a first time for me. Simon C
How did you know the lift pump failed?
See post 3..
White smoke from a no start is usually excessive fuel. If it was bad fuel or starving I don’t think it would shake violently. Usually that’s from one cylinder getting flooded by the injector that is dumping fuel. Usually running bad fuel with water can damage the check valve inside of the injector causing this issue. Still try to run fuel from a bucket to check off the fuel and suction leaks.
Komatsu also likes to use banjo fittings with sceens inside on the fuel system. Just something else to check.