Problem; Motor grader starts right up fine whiten seconds runs itself out of fuel. Action taken; Blew out fuel lines, replaced fuel lift pump, replaced 2-stage filter, removed fuel tank cleaned out with acid/power-washed @250*, removed injector pump and installed newly rebuilt unit (Stanadyne), replaced fuel shutoff valve with a JD valve with a 2 inch stem. Same problem, starts, runs for a few seconds then shuts down. Thought I'd put this out to see if anyone has experienced this issue on this equipment as I've exhausted my capabilities.
Did you blow out the return line also? both off the injection pump to the injector low pressure return, and also from the injectors to the tank if it's plumbed that way. sometimes blowing through with air isn't enough, air will go through and loosen but fuel will compact and plug. If you have a diaphragm lift pump that has a priming lever, operating that lever will tell you if the fuel is pumped up as the lever will go soft, or if you're pulling a vacuum the lever will be harder to operate.
If this machine has the steel fuel lines with those little pain in the ass rubber grommets on the ends........replace every single grommet. I don't know how many times I have run across those that were tight but allowed air to be sucked into the fuel system.
Plugged return line somewhere? Had a deere tractor that would keep blowing the plastic leak-off couplers off the injectors. Fought it for days. My dad and i were discussing it and he told me it had a fuel leak that he fixed a few days previous. I asked where. He said nowhere where it leaks now, so that couldn’t be it. So i said show me. It was up under the cab near a mount where the return line runs back to the tanks. He had taken the steel line off and brazed it. Unfortunately the line was mostly full of brass, restricting the return. Had another case where a couple guys rebuilt an engine and it would only run a few seconds. They had left the return line capped and caused the injectors to hydraulic lock
Actually I was primary focusing on fuel delivery and totally overlooked the return lines. I ordered a fuel pressure tester to measure lift pump output, but in the meantime will check all return lines. Update to follow, thanks.
It does have the hard lines, but uses steel crush washers at the injection pump. Other ends are compression fittings. Thanks...
Seems to be the general consensus on return lines. I had to get away from it for a few days to keep my sanity, and ordered a pressure tester, update to follow. Thanks
The rubber grommets are on the "return" off the injectors that T to each other, and usually the return from the injection pump, back to the tank. Ideally, you'll tee into the fuel supply line at the filter, run a line to the cab so you can monitor it as it starts, runs and dies. Bleed the air out of the line so you get faster response on the pressure reading.
Wanting to provide feedback on this road grader. Everyone here who pointed me at the return line was correct. I did blow out all returns, checked pressure to and from pump and was ok. Started digging deeper in the pump and on the return side it had a internal check valve installed. My old pump had a external check valve on the line. Being one who puts things back together EXACTLY as they were, I installed the old check valve on the return line. Had no clue return pressure was so sensitive, but didn't like having 2 check valves on return. Thanks to everyone here who provided feedback and pointed me in the right direction. I'll see if I can close this thread.