Hey, guys any advise would be appreciated my dozer has something going on with the tracking speed . The machine is going along fine and then slows down and speeds back up out of nowhere without touching the speed control lever.it may not do it for a week and then does it every 10 minutes.its not showing any codes on the transmission computer, electrical? Fuel flow? Anyone ever had or heard of this problem? Thanks in advance jd
I'd suspect air entering the suction side of the low pressure fuel system. If enough air is getting in, it will cause stalling somewhat randomly. Some air can be handled by return lines from the injection pump and injectors, but if there's enough getting in, it will pump air out the injectors instead of fuel until they auto bleed. If not I'd say governor issues, but that's much less likely. A plugged fuel filter could cause similar trouble too.
hey, thanks totalloser do you think it might be a loose fitting at the lift pump? or should I pull out the floor and trace the line back to the tank. any way ill try both, great advise brother. thanks jd
I am not familiar with that engine yet, but those are typical symptoms of air getting in the lines. I would concentrate on the tank side of the lift pump since that's the side that draws a vacuum. The other side would leak fuel rather than pull air. Starving for fuel can cause a similar symptom though. Most injection pumps have a return line that allows fuel to return to the tank, and air goes with it. This usually funnels any air that sneaks in back to the tank. Most injectors are "auto bleed" type so every time they get pressurized, a small amount of fuel goes into return lines or into ports in the head that go to the return line to the tank. But if there is *enough* air, these systems cannot handle it. They are relatively low volume systems. If enough air gets in, then it starts pumping way to little (if any) fuel to the injectors, and the engine stalls out, hiccups, farts, then loads up to regain it's governed speed belching a puff of high load black smoke. The smoke often is significantly dark due to some injectors getting full fueling trying to make up for others that are still purging air. If this sounds familiar, I'd be thinking air leaking in. If it's just bogging down, without the stumbling and heavy smoking, I'd be more suspicious of fuel obstruction- starting with the fuel filter, then moving to soft lines and inlet screens. One other way to eliminate this as the problem is to simply put some diesel in a small bottle and feed the injection pump directly. Good luck with it.
I'm with Loser, sounds like fuel starvation. Take the suction hose off the transfer pump and blow back into the tank, it should bubble easily if the fuel isn't too high. If you can't blow it out by mouth, try compressed air. Or just take the fitting off the tank and clean the screen inside.
yea thanks delmer im gonna bring it in to my shop this weekend or next week and pull off the belly pans ,floor boards and pressure wash every thing so I can see what going on / and see if I can find a bad spot in the fuel line or a loose fitting. it hasn't bogged down in a week of use (about 25 hrs of use)but my son said it was sputtering once in a while and hard to start a couple times .I hope I can find it once I get in there have a look .. thanks
Check Fuel cap has a vent in it. Try some brake clean and blow air through vent in cap. Try and leave cap a little loose while running to see if runs any better