John Deere 6300 fuel system??

[alabama]

After my JD 6300 sits for a week or two it won't start. I have to bleed the fuel system at the injectors in order to start it.
I noticed a little fuel leaking around a frayed hose running from the tank to the filter so I replaced it. But the problem only got worse. Now if it sits 2 days it won't start.

I have ordered the return hose and plan to put it on today. I just wonder if I a headed the right way. I hate to just replace parts for nothing.

 

[dyates]

Injector pump, transfer pump, or check valve. Unless you still have a leak, one of these items is allowing pressure to bleed backwards into the tank, resulting in a system that has to be primed when you start.

 

[cfpinz]

Small things like that will drive you nuts. I've got an old Ford 7600 with two tanks, one above the injection pump and one below the floorboards, the top feeds into the bottom. If I run the top empty and park it for a few days when it's below 40 degrees, it will lose prime like yours. There's an o-ring or fitting somewhere that shrinks just enough with colder temps to let in air. Been that way for 5 years, I just keep the top tank full.

Does your tractor have a seperate transfer pump?

 

[john250]

Do you have a red light that comes on when you turn the key? Do you wait for that light to go off before you turn the key to the "start" position?
I have a 6615 and I am guessing that the 6000 series are all the same in this procedure.
The fuel pump is running while that light is on. The light goes off when everything is pumped up and ready to run.
I replaced a fuel pump at 1500 hrs. Is yours working OK?

 

[Mat Man]

Check or replace gaskets or o-rings on fuel filters.

 

[alabama]

I went to the parts book just to look at the system. They show two different supply lines. Mine is just a line from the tank to the filter. The book also shows another alternative that I guess was a later modification. This one shows a check valve between the tank and filter. Well I have ordered a check valve to put in mine. I hope it helps. I have also picked up a new fuel filter but I have not installed it yet.
When I turn on the key I can hear the pump in the tank running but it does not stop if I let it run. I suspect it would run all day if I let it. I guess it runs all the time when the tractor is running. I don't have a light on the dash for the fuel pump.
I have made the following changes so far.
1) New supply line from tank to fuel filter.
2) New return line from last injector to tank.
And both needed replaced. They were cracked and the supply line was leaking at the tank connection.
When the check valve comes I will put it in the supply line.
BTW the tractor has 1912 hours and 10 years old.

Thank y'all for your help so far.

 

[Mat Man]

Most electic pumps build up to a certain pressure than cut off.You my want to check on the specs of your pump.
Or it my just not be buildind enough pressure.

 

[cfpinz]

Most electic pumps build up to a certain pressure than cut off.You my want to check on the specs of your pump.
Or it my just not be buildind enough pressure.

Good thought. Could be an internal leak that prevents the pump from building enough pressure to cut out.

On an aside, I have two friends that had to have injection pumps put on their 5420's within a year or two of buying them new. Don't know enough about JD's to really make any specific suggestions, though. Sorry.

Please let us know what the problem was when you find it.

 

[Jim62]

The new line from the tank to the filter SHOULD have fixed it. My 6300 did exactly the same thing about a year ago, and about at 10 years old. When I called the dealer, they knew exactly what the problem was. I started describing what it was doing, and they continued the story just like I would have. The original fuel line is a rubber hose that has some kind of braiding in it. This breaks down over the years, and starts to seep fuel out as the tractor sits. Thus, it will start up just fine, and run for a few seconds on what was in the pump, and then die. Will be extremely hard to start then, as the lines have to fill back up with fuel. Mine was leaking worst, it seemed, under the floorboards about where the clutch pedal is. Once they replaced that line, the problem was solved immediately.

I have made that same observation about the fuel pump. I don't think it would ever cut off. I think there must be a pressure regulator involved there somewhere, and after it gets built up, the fuel just does some kind of bypass and goes back to the tank.

That check valve do sound like a good idea, though.

 

[Tennessee Cattleman]

If my 6300 sat more than a day it would get air in the fuel system. The check valve on most the early 6000 series tractors are located in the tank. I put a check valve in the hose coming out of the tank & that solved the problem. Deere dealers stock them.

 

[DiamondSCattleCo]

The fuel pump is functioning as it should. Electric pumps do not run for a little bit, then shut off, but rather are bypassed (internally or externally, right at the pump or further down the line somewhere). Turning a pump on and off like that would reduce its life expectancy to a tenth of what it should be. Some systems do have their pumps briefly light up (10 seconds or so) when turning the key to run, then shut down until the vehicle/equipment is fired right up, but then they'll stay running all the time.

These leakdown problems are often difficult to find. Since you've replaced all the lines (one of the first steps), starting at the tank and working forward:

1) check fuel pressure (pressure, not volume) at the lift pump. A worn pump or damaged bypass will allow fuel to leakdown and this will generally show up with a pressure check.

2) check the external bypass (if so equipped). These are difficult to check without the proper tools. Replace it if it looks even remotely worn.

3) inspect the check valve if so equipped. Most systems have check valves in the transfer pump, but yours may not. Pull the valve off, rig a line to the outlet and pressure it up with whatever pressure the system should be running at. It should hold pressure for hours on end.

4) replace the fuel filters. If these are leaking down, it should be pretty obvious externally.

After the above, you're pretty much done doing things in the backyard. After that its:

1) Injector pump return leaking down.

2) Injectors leaking into the cylinder. Does the tractor smoke alot when starting up? Has it been getting worse?

3) Injector return leaking. This is one of the hoses you replaced I believe.

Good luck, hope this helps.

Rod

 

[alabama]

Thank y'all for your help. I think that replacing all the lines has fixed the trouble. I bought a check valve but have not instaled it yet. i think I will put it in next time I have it in the shop.