Bleeding air from Ford 3930?

[Jason280]

I've run into an odd issue with a Ford 3930 3cyl. We've had the tractor close to 10 yrs, and never had an issue until a couple weeks ago. While bushhogging, it started choking down a bit...and acted like it was running on half throttle. I assumed the filter was clogged, so I pulled it..looked fine. Went ahead and changed it, bled the lines, blew out the cutoff, and tractor ran normal....for less than an hour. Went back to running like it was on half throttle again, so I pulled the entire sediment bowl/filter housing. Noticed that fuel was barely trickling out of the cut off under the tank, so I drained all the fuel and pulled the cutoff assembly. The screen was completely clogged with algae/whatever you call it, so I went ahead and cleaned out the tank and screen. The sediment bowl was also fairly dirty, so I cleaned it as well. Reassembled everything, bled the lines, and its still running like its on half throttle.

It still acts like it has air in the line, so I am not sure if I'm missing some procedure for this particular tractor. I get good flow out of the cut off, and plenty of fuel out of the filter bleed screw. I first start bleeding the filter housing, then go to the injector pump bleed screw itself. Now, it doesn't have as much fuel pouring out as the filter housing, but I'm still getting fuel flow. I've also bled all three lines at the injectors...each individually, and then 1 at a time to make sure I am not missing something. Problem is, I'm still getting the same result...acts like it has air in the system.

The fuel filter looks good, I've never seen any trash/growth in the filter housing or filter itself (even with the old filter). All the O-rings were changed, so I am not sure what I am missing. Only thing left to do that I know is pull the individual line from the filter housing to the injector pump to check it, as well as all the injector lines to the injectors themselves.

Any other suggestions? Is there a special procedure for bleeding Fords?

 

[true temper]

Sucking air in the fuel line somewhere.

 

[RjCorazza]

Unlikely (but still possible) that you are dealing with multiple issues. I would go back to the tank and reclean, rinse the water separator and element, and replace the filter again. A slug of gunk after the tank will wreak havoc.
Bad fuel and algae problems can require several attempts to clean out.
Next on the list would be to add an algaecide to your fuel tank, and storage if applicable. Also find out how water is getting into your fuel, and fix that!

If there is a secondary problem, I would suspect dry rotted fuel lines or bad connections. For rubber lines, bend them to check condition and for obvious cracks that could introduce air.
Good luck... Fuel issues can be a real pain.

 

[thepumpguysc]

Did u put the top oring UP IN THE FILTER HEAD.??
It HAS TO GO UP IN THE FILTER HEAD, or it’ll choke off the fuel..

 

[Jerry/MT]

I've run into an odd issue with a Ford 3930 3cyl. We've had the tractor close to 10 yrs, and never had an issue until a couple weeks ago. While bushhogging, it started choking down a bit...and acted like it was running on half throttle. I assumed the filter was clogged, so I pulled it..looked fine. Went ahead and changed it, bled the lines, blew out the cutoff, and tractor ran normal....for less than an hour. Went back to running like it was on half throttle again, so I pulled the entire sediment bowl/filter housing. Noticed that fuel was barely trickling out of the cut off under the tank, so I drained all the fuel and pulled the cutoff assembly. The screen was completely clogged with algae/whatever you call it, so I went ahead and cleaned out the tank and screen. The sediment bowl was also fairly dirty, so I cleaned it as well. Reassembled everything, bled the lines, and its still running like its on half throttle.

It still acts like it has air in the line, so I am not sure if I'm missing some procedure for this particular tractor. I get good flow out of the cut off, and plenty of fuel out of the filter bleed screw. I first start bleeding the filter housing, then go to the injector pump bleed screw itself. Now, it doesn't have as much fuel pouring out as the filter housing, but I'm still getting fuel flow. I've also bled all three lines at the injectors...each individually, and then 1 at a time to make sure I am not missing something. Problem is, I'm still getting the same result...acts like it has air in the system.

The fuel filter looks good, I've never seen any trash/growth in the filter housing or filter itself (even with the old filter). All the O-rings were changed, so I am not sure what I am missing. Only thing left to do that I know is pull the individual line from the filter housing to the injector pump to check it, as well as all the injector lines to the injectors themselves.

Any other suggestions? Is there a special procedure for bleeding Fords?

If you had crap and corruption in the tank there is a good chance you have the same stuff in the filter head (the casting that holds the filter). Check the filter head where the fuel enters the filter.

 

[azbinder]

There is a plastic filter screen in the back end of the injection pump where the fuel line comes in. Item #30 in this breakdown. Check and make sure that it is clean. A lot of people don't realize that it's there.

New Holland 3930 - 3 CYL AG TRACTOR ALL PURPOSE(05/90 - 07/99) Parts Diagrams

New Holland Parts Catalog Lookup. Buy New Holland Parts Online & Save!

www.messicks.com

 

[Jason280]

It will be a couple days before I can get back to it, but I'll check the filter...makes sense that it might be clogged.

Looking at the schematic you posted, what is the point of the solenoid assembly/terminal (#75 & 76)?

 

[azbinder]

It's been so since I've been around one of these that I really don't remember what it's for. Maybe someone else can chime in.

 

[thepumpguysc]

That’s an electric shut off solenoid..
There are 2 different pumps that went on the engine, depending on the year..

If your going to dig around in the pump, u had better know what yer doing.!!

 

[Jerry/MT]

I've run into an odd issue with a Ford 3930 3cyl. We've had the tractor close to 10 yrs, and never had an issue until a couple weeks ago. While bushhogging, it started choking down a bit...and acted like it was running on half throttle. I assumed the filter was clogged, so I pulled it..looked fine. Went ahead and changed it, bled the lines, blew out the cutoff, and tractor ran normal....for less than an hour. Went back to running like it was on half throttle again, so I pulled the entire sediment bowl/filter housing. Noticed that fuel was barely trickling out of the cut off under the tank, so I drained all the fuel and pulled the cutoff assembly. The screen was completely clogged with algae/whatever you call it, so I went ahead and cleaned out the tank and screen. The sediment bowl was also fairly dirty, so I cleaned it as well. Reassembled everything, bled the lines, and its still running like its on half throttle.

It still acts like it has air in the line, so I am not sure if I'm missing some procedure for this particular tractor. I get good flow out of the cut off, and plenty of fuel out of the filter bleed screw. I first start bleeding the filter housing, then go to the injector pump bleed screw itself. Now, it doesn't have as much fuel pouring out as the filter housing, but I'm still getting fuel flow. I've also bled all three lines at the injectors...each individually, and then 1 at a time to make sure I am not missing something. Problem is, I'm still getting the same result...acts like it has air in the system.

The fuel filter looks good, I've never seen any trash/growth in the filter housing or filter itself (even with the old filter). All the O-rings were changed, so I am not sure what I am missing. Only thing left to do that I know is pull the individual line from the filter housing to the injector pump to check it, as well as all the injector lines to the injectors themselves.

Any other suggestions? Is there a special procedure for bleeding Fords?

"...Now, it doesn't have as much fuel pouring out as the filter housing, but I'm still getting fuel flow...."

What does that tell you?

 

[Jason280]

There is a plastic filter screen in the back end of the injection pump where the fuel line comes in. Item #30 in this breakdown. Check and make sure that it is clean. A lot of people don't realize that it's there.

Thanks, I believe that was the problem. I pulled the assembly, not sure what its called, and the filter had some junk on the screen. Cleaned it all up, and the tractor seems to be back to normal.

I do know that "cover" assembly (#39 in the schematic) houses a bunch of different things, including the filter...several springs, some sort of hydraulic valve, and a couple of other random parts. The schematic doesn't really show how everything is assembled, at least not very well. Reassembly had me a little nervous...

 

[thepumpguysc]

That’s why u should do ur homework BEFORE digging into a pump..
U SHOULD HAVE removed the large nut, remove the big spring.. THEN.. hold the guts down with a pocket screwdriver while using a 90* pick to grab the filter screen and pull up..
THAT WAY.. u don’t have to worry about disturbing the regulating sleeve, springs and piston..
Glad u figured it out & got’r running..