RD4 Injection Pump problem

Not much you can do to check pumps without having the test apparatus where there is a set number of strokes to deliver a specific quantity of fuel at a given rack setting.
The 4-1/4 bore engine uses 8mm pumps.
You can check the overall plunger length for wear. New is 2.6575 - 2.6577 in. and they are considered worn out at .005 in. wear.
(I need that length verified for both the tall and short pumps as the manual is not real specific. I know it is right for the short pumps)

Usual process is go to the spare parts barrel and start swapping out units until ya get some that work😉 😉

Well, I wonder where I can find 2 pumps, I don't know if anybody else knows, but RD4 pumps are a little different than the D4 7j, the later pumps have an extra little notch on the pump piston, I don't know if they will in interchange, also i do know that the piston should stay with each pump, and not interchanged,

There should be a number stamped on the side of the pumps. I only show two pumps in my info that goes back that far. A 2A3895 that is shown on the 7J1 and a 9B1411 that I can't identify.
Based on the info I see in the rack setting manual I'm pretty sure you could change to the later pumps but I'd do it as a matched set. Need someone with a 4G parts manual to verify the numbers. (edb where are you???)
Correct, pumps and barrels are matched sets and should not be interchanged.
(Wouldn't stop me from trying if I was stuck out in the back woods with no other means to get out😉 )

Pat, assy is 2A3985 for all housings 7P1-7P13755 on the 4400

The visible area on pump plungers to check for wear is at the top of the plunger where that curved groove is & from the groove up to the tip they will have up & down wear there in that area that is very visible when you pull the plunger out of the barrel.A little wear at the bottom you can always set the lifters a couple thousands higher to make it up but the main wear is the scuffing at the top of the plunger.It is best to have them checked out at a fuel inj. shop that has the equip. to do it.

Along with the plunger and bore wear there is a check valve at the top that eventually wears out. There are no service parts available (never was that I know of) for these pumps so if they can't make test it is replacement time.

SJ, I was wondering if you would have any connections to a shop that would have any test equipment, nobody around the North Texas area that can check them.

Thanks Pat

The dealer I worked for has a fuel testing shop but is in Harrisburg Pa. so is pretty far from you unless your not in a hurry & you could ship them to their shop to check & then return them.If you are interested you can call 888-232-5948 & ask for the fuel injector & pump repair shop in Harrisburg or other shops of there,s that do it as they have shops in western Pa. too now.For the 36 years I worked for them the fuel inj. shop was in Harrisburg so I have sent 100s of them down there over the years from the Wilkes Barre Pa. branch & always worked like new when they came back.All of their branches sent them to that one central center for testing.

Thanks SJ

I'm not in a real hurry, I will probably sent them up there if I don't find any other alternatives

Pat