Rebuilding the Injection pump

[Floridianson]

Greg is correct in saying when at 1200rpm and correct pressure is established the FDC starts to compensate and moves to it correct position for the fuel being used. So it does move from when we start till 1200rpm then settles to the correct position. I have not tested the fuel pressure at 1200rpm so if Rusty says it's 60 psi then that is the pressure where the FDC is doing it's compensation for that fuel. I don't mess with FDC calibration as I will bypass them as soon as I get the truck.

Since digging into the TM's again I was wrong and the FDC with is pressure regulating valve and orifice keep the pressure at 20/ 21 psi. So as soon as the engine starts and we have the 30 psi min. then at 1200 FDC goes to the setting for that fuel and stays there. Page 1-30 /1-31 TM paragraph C. The 60 psi was for when the FDC is calibrated / tested for leakage on the bench. Guess it pays to read everything even attachments.
Sorry stb64 I have not worked on Deuces for 12 years I switched to the big boys. As a side note if you believe the TM not all IP's had a droop screw like C&D IP's.

 

[rustystud]

Since digging into the TM's again I was wrong and the FDC with is pressure regulating valve and orifice keep the pressure at 20/ 21 psi. So as soon as the engine starts and we have the 30 psi min. the FDC goes to the setting for that fuel and stays there. Page 1-30 /1-31 TM paragraph C. The 60 psi was for when the FDC is calibrated / tested for leakage on the bench. Guess it pays to read everything even attachments.
Sorry stb64 I have not worked on Deuces for 12 years I switched to the big boys. As a side note if you believe the TM not all IP's had a droop screw like C&D IP's.

The FDC plate will constantly move according to what pressure is exerted against the piston. There is no "regulator" in the FDC which would hold pressure at a constant.
During "testing" of the FDC you would use a "constant" pressure and the FDC would be expected to hold the appropriate pressure. That is the only time it would be holding a steady pressure.

 

[rustystud]

OK, since there still seems to be problems with people "visualizing" this FDC movement. I'll post a picture trying to show you what is happening.
When different fuels are used the "Servo Piston" will move into different areas on the "moveable plate" . I've marked these areas to show you what I mean. Now within these areas the moveable plate will continue to move according to fuel pressure.
So for example when using diesel fuel the moveable plate will move up to this area and stay within this area making small adjustments constantly according to fuel pressure.
If you used only Gasoline ( Not recommended !!! ) the moveable plate would move down to this area and stay within this area making small adjustments according to fuel pressure.
Does this make sense for everyone ?

 

[Floridianson]

TM-9 page 1-30 & 1-31 FDC pressure "regulating" and FDC working pressure 20-21 pounds.

 

[rustystud]

TM-9 page 1-30 & 1-31 FDC pressure "regulating" and FDC working pressure 20-21 pounds.

Exactly. When "adjusting" the FDC you will need to keep this pressure . Not when the injection pump is on the vehicle.

 

[Redleg130]

View attachment 673125

With a helpful tip from Big Mike, who recommended foot powder on a clean part, I was able to isolate a slow fuel leak to the hydraulic head top center fastener (not sure what to call this) - the one in the center of the fuel lines as they leave the hydraulic head towards the cylinders. Mine has no (rubber) seal on it, just a bevel machined into it towards the bottom of the length of it.

In any case it appeared to have a paint chip on the bevel so I removed that, cleaned the part, and reinstalled it. It runs dry now, so it appears to be fixed. Any tricks to this fastener or is it just holding this part together?

I didn't see this fastener specifically mentioned, or I missed it in the discussion.

I think I found the name, "Plunger bore screw", but no notes or specifics on it.

 

[cattlerepairman]

You are right about this plug not having any sealing washer. A common jungle fix, when they leak, is to put a copper crush washer underneath. Good that cleaning and re-seating stopped the leak.
As the name suggests, there is a plunger underneath this plug. If your truck won't start and the fuel shutoff is indeed released, one thing to check is that the plunger beneath the plug is moving along its full stroke; if not there is a clip at the bottom that has likely fallen off.

 

[Redleg130]

Bummer, it didn't hold, it is leaking after driving it a bit, much slower but leaking. I didn't see a torque anywhere, I did 50lbs since I am worried about breaking it. I assume teflon tape or something wouldn't help in this high pressure area?

 

[cattlerepairman]

The search function is your friend. Torque spec is 65-70 ft-lbs.
See copper washer above.

Hydraulic Head leaking need advice!

I have been looking at the TM for the IP and have not found a breakdown of the Hydraulic head... Mine is leaking at the area under nuts where the 6 lines attach at the top. I am wondering if I have to replace the whole Hydraulic head or can I just replace some o-rings... I drive this truck...

www.steelsoldiers.com

 

[Redleg130]

Thank you very much for digging that up, I must have missed it. Copper washer seems to work, it is dry after a highway run. I really appreciate your suggestion.


I was worried about the gap added with the washer, but it seems to have no negative effect on performance.

 

[Floridianson]

Just looking.

 

[Davidwyby]

You are right about this plug not having any sealing washer. A common jungle fix, when they leak, is to put a copper crush washer underneath. Good that cleaning and re-seating stopped the leak.
As the name suggests, there is a plunger underneath this plug. If your truck won't start and the fuel shutoff is indeed released, one thing to check is that the plunger beneath the plug is moving along its full stroke; if not there is a clip at the bottom that has likely fallen off.

3/8”, not 3/16” travel