Have a 444J in the shop with the 4045HDW52 engine and DE injection pump RE518167 - 11,000 hours on machine Machine will run good for days or even weeks and then have an issue where it barely runs at wide open throttle. Sounds exactly like an issue of lack of fuel when it misses. (Runs normally at idle). Customer will change the fuel filters and bleed system and it will then start and run properly for another few days or weeks. He has also changed the filter housings and mechanical lift pump. I plumbed into the final filter test port and didn’t have enough pressure to even noticeably move the needle on the gauge. Maybe .5psi. Specifications have shown to be at least 4psi. I removed the suction tube from the tank and inspected the entire fuel delivery system for obstructions or other issues. Currently using a pail as an alternate fuel source with the suction hose directly to the lift pump and then going through the final filter. Removed the return hose from the tank and I have full fuel flow with considerable pressure constantly back to the tank but the inlet port does not build any pressure. I changed what Deere called the pressure regulating assembly in the pump but it was essentially just a check valve in the return fitting and did not make a difference. Is there something internal in these DE pumps that can allow the inlet fuel to bypass to the return without building any pressure? I have changed many of these DE pumps on 6015 & 6020 tractors but the issue has always been electrical with the solenoid. Anyone had an issue like this?
Welcome to HEF DeereMan99 ! When posting, please provide the machine's serial number. Are you measuring 0.5 psi with the separate fuel supply? When the new fuel transfer pump was installed, did you check plunger movement in the head? Do you have an electric fuel pump to temporarily try? Also, has anyone checked that the seal between the glass bowl and the water separator filter is there?
Yes i didn’t have any pressure with the separate fuel supply either. Glass bowl isnt present anymore but seal is present between the filter and the drain fitting. I will have to check that the plunger in the head is moving fully. I didn’t check that when transfer pump was off because the fuel does pump well just doesn’t build pressure. Yesterday noticed the engine oil overfull and diluted with fuel. Tested the transfer pump and it does not leak. Have an injection pump on order now.
Hmmm, the plot thickens. Sounds like you are on the right trail.
In case anyone has a similar issue in the future and comes across this post I changed the injection pump and immediately had 5-6 psi inlet pressure at idle and 3-4 at wide open. Machine has been running great