AC 5050 Fuel Problems ???

CurtisJ

New User
AC5050, will run fine for 1 - 2 hours, then quits. Have replaced all fuel filters, and rubber lines. Fuel tank has been removed and cleaned twice. Fuel pump screen clean.
 

Welcome to YT
I presume engine is diesel powered. If that's correct what type inj pump? My 1st guess is fuel return line check valve at IP is clogged.
 
(quoted from post at 12:14:58 11/11/17)
Welcome to YT
I presume engine is diesel powered. If that's correct what type inj pump? My 1st guess is fuel return line check valve at IP is clogged.

Tx Jim, you are correct, it is diesel. Have no idea what "type" injection pump. How do I find, clean or whatever the return line check valve. My operators manual does not show a check valve. appreciate your quick response.
 
My 5040 has a CAV DPA pump. Mine does not
have a check valve in the return. There is
a small filter in the pump under the feed
line that you may need to check.
 
(quoted from post at 13:48:27 11/11/17) My 5040 has a CAV DPA pump. Mine does not
have a check valve in the return. There is
a small filter in the pump under the feed
line that you may need to check.

Steve-in-ga, Thanks for responding. I don't know where to look for a return check-valve. That said, I didn't see anything on the injection pump that looked like it was something that required maintenance. Fuel from the tank to the fuel pump is free flowing. It almost seems that after running for time, air gets into the fuel system. I've mad sure all connections are tight, but that hasn't solved the problem
 
Next time it happens loosen the return line
to relieve any pressure in case your pump
does have a plugged check valve and see if
it will run. I've got a different tractor
that I have to keep at least a half tank of
fuel in or the feed pump cannot supply
enough fuel to the injector pump or it will
get air in the fuel system.
 
(quoted from post at 14:34:00 11/11/17) Next time it happens loosen the return line
to relieve any pressure in case your pump
does have a plugged check valve and see if
it will run. I've got a different tractor
that I have to keep at least a half tank of
fuel in or the feed pump cannot supply
enough fuel to the injector pump or it will
get air in the fuel system.

Steve, again, thanks for the quick response. I'm not sure what return line you are referencing. I have 2 lines returning to the tank. Line 1 comes from the secondary fuel filter, line 2 comes from "Thermostart Fuel Reservoir" (whatever that is.)
 
If I recall that fuel system has a constant air bleed fitting on top of a filter base like Perkins uses. It's there to bleed any trapped air from the filter assembly. When the small orifice gets plugged, any trapped air will go to the injection pump and cause immediate shutdown. Engine will then need air bled to get started. Look for a banjo type fitting that has a small line that either goes across the injector top bleed line, or goes straight back to the tank. The bleed orifice is in the side of the bolt, or if no banjo might be a straight orifice fitting with a small line on top. Remove the line and work the hand primer, fuel should come out. Also be aware if NAPA/WIX brand filters are used, make sure the filter top outer groove has NO O ring in it, that's the fuel inlet passage on that style filter. An extra O ring there WILL restrict or shut off fuel flow completely. Have seen that mistake made often in over forty years diesel injection repair.
 
Is your fuel tank fuel cap vent hole open? Let the cap loose and see if it keeps running. These guys that are asking about the check ball are thinking Roosa Master and you have a CAV model DPA.
 
(quoted from post at 15:18:50 11/11/17) If I recall that fuel system has a constant air bleed fitting on top of a filter base like Perkins uses. It's there to bleed any trapped air from the filter assembly. When the small orifice gets plugged, any trapped air will go to the injection pump and cause immediate shutdown. Engine will then need air bled to get started. Look for a banjo type fitting that has a small line that either goes across the injector top bleed line, or goes straight back to the tank. The bleed orifice is in the side of the bolt, or if no banjo might be a straight orifice fitting with a small line on top. Remove the line and work the hand primer, fuel should come out. Also be aware if NAPA/WIX brand filters are used, make sure the filter top outer groove has NO O ring in it, that's the fuel inlet passage on that style filter. An extra O ring there WILL restrict or shut off fuel flow completely. Have seen that mistake made often in over forty years diesel injection repair.
Dieseltech, I think you might be on to something here, right now it's dark so I can't check it immediately. My fuel system looks a lot like the diagram at http://www.importtractorparts.net/3cylfuelsystem.html.
The only difference I see is the top of the secondary fuel filter has a hose that goes nowhere in the diagram, but on my tractor goes to the "Thermostart Fuel Reservoir" which has a hose going back to the fuel tank. Is this what you are referring to ? Everything you mentioned about having to bleed before it will start again is true here.
 
Thanks for replying to my problem. I have not checked the fuel tank cap, but when I remove the fuel tank line at the fuel pump, I get good fuel flow.
 
(quoted from post at 18:55:15 11/11/17) Yes, the line to the thermostart reservoir usually is the filter bleed line, fills the reservoir, then overflow is returned to the main tank.
Thanks for response, will try that first thing in morning.. I sincerely appreciate your help and suggestion. Do you have any idea what a rebuilt injection pump might cost, or where I could get mine rebuilt IF NECESSARY ??
 
Most pumps like yours I repair usually run three to four hundred for a complete tear down, clean, reseal, calibration test, and return. You have several things to check out first though..
 
NOT sure what you've got going on, but injection pumps don't randomly quit after an hour or two.
 
What is happening is typical of the lift pump getting ready to go bad on those Fiats,they'll run for awhile then just quit.I've had the one on my Oliver 1365 go bad twice acted the same
both times.The after market pumps are hit or miss got one from New Holland last time for my 1365 4WD and its not given me any problems.
 
Check the tank for thing floating around. I had a 15 minute 574, discovered a piece from a siphon
floating over the fuel pickup. After the tractor would quit, the piece would float away and everything
looked normal.

Bill
 
Good idea and also the outlet on those tanks are very restrictive,I had to take the cut off valve out of the tank on my Long 460 and drill a hole up thru the inlet hole to get
a good fuel flow.
 

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