Oil & Fuel TC45D Fuel Vent Problem

[burtrl]

The lift pump may be creating just enough suction to suck the air past the o-ring. I'll know next week. My dealer had to order the o-ring and wont get it until next week.

 

[jinman]

Since we are waiting on Burtrl to get his gasket, I'm posting a block diagram of the fuel system and a description of Auto Bleed. There are several issues that may have a bearing on where the filter could be getting air, but not from lift pump suction. The lift pump in the diagram below is before the filter, so the filter would never see suction, only pressure will be applied from the lift pump. Of course, if the lift pump is drawing air from a leaky connection in the feed line, then that will go through the pump and into the filter.

Also, consider the following. If you read items 3 and 4 in the description of auto bleed, you see that the injection pump sends air in the lines to the injectors where it is directed back to the return to tank line and T'd into the bleed line coming from the fuel filter. Since there is no checkvalve in the outlet at the top of the fuel filter, any clogging or restriction of the fuel return line will cause air to flow backwards into the top of the fuel filter and collect there. It seems that NH put a checkvalve in the fuel tank, but did not put one between the fuel filter and the return line T. This means that if the fuel tank cap becomes clogged so that positive pressure is in the tank, it cuts off the checkvalve at the return inlet and air cannot return to the tank, but rather build up in the top of the filter. That's why I think Burtrl's tank either has a clogged outlet that won't allow fuel to flow out of the tank or a clogged fuel cap that is holding the checkvalve closed due to internal tank pressure.

See? Isn't this fun creating imaginary problems and coming up with imaginary fixes?:laughing: I apologize for adding more minutia to the mix.:ashamed:

 

[burtrl]

I my tractor the lift pump is after the fuel filter. I would think that yours is also. Check it out!

I believe whaat is happening is that my tank or fuel line is restricted, and the pump is causing a slight vacuum in the fuel filter. If the o-ring is not sealing 100% this could explain how the air gets into the sediment bowl. I am hoping to check out the supply lines this weekend. Hopefully I will have some answers to report back.

 

[jinman]

I my tractor the lift pump is after the fuel filter. I would think that yours is also. Check it out!

You know, you could be correct in that. The diagram could easily be wrong. The lift pump in the diagram I posted could be drawn in the wrong place. It's not the first time New Holland has published an incorrect illustration. If the lift pump (transfer pump) is between the filter and the injector pump as it appears to be, that COULD cause suction on the filter and draw in air. I trusted NH's diagram without looking at the actual parts on my tractor and tracing the hoses. I just looked at a photo I have and it looks like the line leaves the filter and heads for the lift pump. The hose going into the top of the injector pump comes from the lift pump, so this is starting to make sense. When I change fuel filters and drain out fuel with the ring loose at the top, I'm always relying on gravity. I never do that with the engine running. As soon as the engine starts, the lift pump would draw in air if the ring or seal is loose.:thumbsup:

 

[RADIUM]

One other thing when you look at the old O-ring it's really not that crushed or damaged. Another problem I've noticed the sediment bowl is starting to glaze and cracks are developing looks like I'll be changing it next filter change, why they're not made out of glass with a peacock in the bottom to drain water I'll never understand? LOL my father's 1961 JD has a glass bowl still going strong . Its such a pain in the neck every time you need to drain water especially with its location on the T2420. I wonder if it would be possible to put a drain in the bottom of the bowl? Or possibly another manufacturers, sediment bowl with peacock hmmmmm?

 

[burtrl]

Since my last post here's what I have done:

- Replaced the o-ring for the sediment bowl.
- Drained 5 gal of fuel from the tank by disconnecting supply line from fuel filter. This took roughly 10 min to drain... Excellent flow and much more than the engine requires during operation.
- Changed fuel pump.

After all that, I still have the problem. I have to admit at this point I am stumped!

 

[RADIUM]

Sorry it didn't help, did you try turning the valve to the other on positions? Their must be something in that valve causing your problem of slowing the fuel down. Did you try letting the fuel run for a while without the filter installed and was it running just as quick as the fuel line? The only other information my dealer told me sometimes they run half full kind of makes me scratch my head but that's the answer they gave me until I change the O-ring as instructed by my brother, haven't had a problem since that day even down to a quarter of a tank it still stays full in the sediment bowl with no cutting out. One other quick story my brother had an old tractor that no one could keep running he thought it was time for a valve job, clean the filters cleaned the carburetor could not solve the problem you would never believe what was causing the problem a ladybug in the tank would float up and then down and plug the fuel drain line so the tractor would stutter from fuel starvation and then when the tractor would hit a bump it would float off and allow the fuel to flow free LOL could not believe that little body would not deteriorate for almost 3 years that little shell plug the hole perfect each time, perhaps you need to take your tank off and wash it out good. Take care