Help! TN75DA Injection Timing

BlueBlues · Jul 18, 2014

A couple of weeks ago, my 2005 New Holland tn75da suddenly shut down while operating as if the key had been turned off. I spent two days going through the fuel system, had plenty of fuel to the injection pump, pulled the fuel shut off solenoid, etc. and finally came to the conclusion it was the injection pump. I pulled the pump and took it to a reputable pump shop where it was tested and confirmed worn out rollers and cam plate which caused a metal shaving to get into the governor and cut the fuel off. I have re-installed the pump and followed the procedure to line up the 4's on the timing gears and turn the flywheel to 9 degrees before TDC. However, the 4's are one tooth off from lining up and the flywheel marks are nowhere to be seen when the 4's are close. So, I just moved the flywheel to 9 before TDC and unlocked the pump-lock bolt. After bleeding the injectors it only hit once while trying to start the engine. The instructions I am using are for a TN75 that was posted by Tractortech. I have set everything back to where it was when I installed the pump and tried different things with no results. I must be missing some important step or something that is not spelled out in those two pages that are attached to that post. Anybody have an idea what I am doing wrong?

jaotguy · Jul 19, 2014

you might be 180 degrees out on the pump ... rotate the flywheel another revolution then try to reinstall the pump.

Harry in Ky · Jul 19, 2014

jaotguy said:
you might be 180 degrees out on the pump ... rotate the flywheel another revolution then try to reinstall the pump.

Too late for that. With a lock timed pump, once you unlock it with the engine in the wrong place you're dead in the water. You can fight with it for hours and most likely never get running, that's your choice to make. If I were doing it, I would loosen the nuts on the #1 injector clamp and try to pop it loose. Bump the engine and try to establish compression on #1. Once established, set the flywheel to TDC and check the pump gear for the marked tooth(or valley) with #4. This should be pretty close to dead center next to the idler gear. The #4 on the idler will be nowhere in sight, but that doesn't matter as many engines will require 200 or more revolutions before all those numbers will come back in register. Back the engine up a ways then slowly turn it forward to 9 degrees(if that's the spec you want) and leave it there. Pull the pump back off, return it to the pump shop and have them time and lock it down again. Install the pump with the three mounting bolts centered in slots. Tighten them down then torque the nut against the drive gear. I think it's like 70 or 90 ft/lbs, not sure. At this point unlock the pump, and it should start.