Give your engine serial number - and some history. The engine number will tell exactly what pump is supposed to be on there and IF it was ever changed over with an update kit from Deere.
I attached two photos - one of what the pump driveshaft end should look like at TDC and also of the timing pin at the back of the engine.
The AL2405 pump you mentioned should only be on a 1020 with an engine ser. # 117,500 or newer.
I think just about every possible problem has already been explained or discussed in the April posts. Also, I gave you instructions on how to air-time that pump to verify when it's actually firing. Do you ever do that? Also - did you verify TDC via the timing pin at the back of the engine? (not the front crank pulley)
I don't know what pulleys you are referring to when you mentioned . . .
"idler pulley, anf pump drive pulley, and the mark on the pump drive pulley" . . .
- do you mean the timing gears in the front of the engine?
Also - did you check the TDC location by using the diesel timing pin that goes into the engine flywheel? That is the preferred method for verifying TDC on a 1020 diesel - not the front crankshaft pulley.
The connection - from the crankshaft to the injection pump is all gears and a shaft - nothing else. If something is off - it has to be overt.
#1 - the timing gear hooked to the injection pump shaft. Either it's in time, or it's not. Unless - someone either left the little woodruf key out or bent it - where the shaft attaches to the gear. Takes a 5/32" X 5/8" key. That is if your tractor originally came with the JDB type pump. Many 1020s did not and were converted - and those have special conversion driveshafts.
#2 - the pump driveshaft. Has it been changed - and are you sure it's the original and correct? I don't think it can twist and be off since it is designed to act like a "fuse" and snap at its narrow section - if the pump turns too hard.
#3 - if you know all is OK with the aforementioned #1 and #2 . . . then the problem has to be with the pump - which is not possible unless the pump was put together with the wrong parts. Keep in mind thought - most 1020s came with AL2406 pumps - NOT AL2405 - and there is a 1 degree difference between the two in timing marks. Also a difference in fuel delivery.
Beyond that - there is nothing else. If #1, #2, and #3 are correct - it has to be right.
What is the history?
Did it run when you got it and the die?
Did your problems begin after a pump repair?
If you want to read though - here is all my parts and update info for 1020 AG and 300 industrial wheel tractors as it relates to diesel pumps.
R36538 pump driveshaft fits both 1020 and 300 300 industrial
R58103 conversion pump driveshaft used with AR69817 injection pump ( JDB331AL2732) pump, tractors SERIAL NO. 60327-117601 300 industrial SERIAL NO. 117602 ROOSA-MASTER NO. JDB331AL-2405 OR JDB331MD2797 - remanufactured is sold as Deere SE500558 or was new as AR49899
AR70139 original pump AT21576
AL2406 = AR49904 timing line 183.5 degrees 1.979” roller setting 1020 ag
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