Sometimes upon start up it spits and sputters. Yesterday I changed the fuel filter. It wasn't dirty as I expected. It hasn't been on there long. Anyway I had a hell of a time getting it back going again. When it's trying to run I can push on the primer pump on the lift pump and it keeps getting better. Had it running good and it died again. I would crack injector lines in between and bleed them. Got it going agin and just kept pushing primer pump till it finally cleared up. Now it may run just fine or at any given time it may sputter upon start up but will clear up. It seems like it's sucking air but I can't see anywhere that's happening. It did have a leak at one of the banjo fittings and I fixed that and thought that was the issue and it was an issue, but it will still do it sometimes. I'm thinking the lift pump or manual fuel pump whatever it's called is going bad I don't know want to just throw parts at it so looking for opinions. I would imagine that it's pretty pricey as everything else is fr Komatsu. I could put an electric fuel pump on it I guess but I like to keep things stock. Thanks.
What kind of priming pump do you have? A piston type, right? If priming it continuously helps it run smoother, then that's a pretty good sign that the transfer pump part isn't working right. You can test the pressure while it's running if you have a vacuum pressure gauge and the fittings to tee it in. Have you checked your banjo bolts for any screens or blockages? especially the bolt going into the bottom of the transfer pump on Japanese machines. The vacuum gauge will help you find where, but it's just as easy to take them apart and look.
Is your's the Cummins engine? My tag says Komatsu but it's a 5.9 Cummins and all the parts have interchanged. It sure sounds like it has a leak somewhere but if you're sure that isn't the problem, I'd guess the lift pump.
It looks like a Cummins. I'm pretty sure it's bypassing in the pump. I ordered one from Komatsu. $115. Wasn't to bad. Even when I manually pump it it doesn't seem to have much pressure.
Also I figured there was a screen or two in the banjo fitting somewhere. Does anyone know how many or where there at. I've had one of them off that I replaced the copper washers onmand it didn't have any. Thanks
I looked on eBay and theirs a fuel pump for a 5.9 cummins and it looks exactly like the one on my dozer. I haven't pulled mine off but I think it's the same. Maybe a local auto parts store would have it. Plus they're like 25 bucks. I may have to go that route unless it's different spec on the dozer
Put a new one on today got it from Komatsu. It was definitely bad. Wow this thing has power power power hehe.
Kool.. way to go..
Yes sir thanks. When I pulled the old one out the plunger was stuck in the in position. I knew it was faulty at that point. The new one pumped right up hard with the primer pump. The old one wouldn't ever get hard it was toast. Dauum sounds like me. Hehehehe