fuel injection pump issues JD 5205/5105

warehouseman · Apr 3, 2015

I have a tractor 5205 and the fuel injection pump seems to be not working right. I've bled the system according to the manual but the tractor is not starting. It's not getting any fuel to the engine. I've traced the lines running from the fuel filter to the fuel injection pump. Fuel is running from the filter to the injection pump. However there is no fuel running OUT of the injection pump. I've opened the injection lines running out of the injection pump and they are dry. Even when I push the priming pump with the injection lines off, there is no fuel coming out of the injection pump and ultimately to the engine. Is the injection pump broken? There seems to be an air lock in it. How should I proceed from here? Its a Stanadyne injection pump model#9688483

JD5210 · Apr 3, 2015

Are you blowing any fuses? And does the fuse blow as soon as you turn the key? The fuse you are looking for is the one for the fuel solenoid. You can also test if you are getting power to the fuel solenoid.

If yes, to both questions, I believe the problem is the thermistor sensor (thermistors are temperature variable resistors used as sensors.). On the thermostat housing there is a sensor that is connected to a two wire harness that goes to the injection pump; this is the "cold start advance" portion of the system so it starts easier when cold by advancing the timing.

When the sensor on the thermostat housing fails it shorts out and blows the fuse. Try unplugging it, replace fuse and see if it starts and runs. The part # is RE503242, if you are quick changing it, you don't have to drain the coolant, just make sure it's not hot at the time. You will want a pan under the tractor to catch the coolant, so as not too have to clean it up.

To comply with the exhaust emissions regulation, the timing of injection pump should be around 6 to 9 degrees before TDC. These timing values do not allow proper start-up operations when engine is cold. To ease engine start-up, a cold advance system gives to the injection pump a temporary over-timing.

When coolant temperature is below 50 C (122 F), the solenoid valve is activated and opens the cold advance circuit.

URL to JD parts
jdpc.deere.com/jdpc/servlet/com.deere.u90490.partscatalog.view.servlets.HomePageServlet_Alt

texstrk426 · Dec 29, 2024

The picture shown looks like a part I see that screws into what appears to be part of the engine block below the injector part. Is that perhaps the one you are describing?

On my 5105 I discovered that the engine starts but as soon as I release the key back to the run position the 12VDC goes away from the fuel solenoid on top of the fuel injector pump. I did discover that if I unplug the bottom left relay from the bank of 6 relays on the left side under the dash area that the tractor starts as good as new and will continue to run with 12VDC on the fuel solenoid on top of the fuel injector pump. Is there a picture of that relay bank that explains the function of each relay?

Harry in Ky · Dec 29, 2024

I don't have a book on that model handy at the moment, but you might be having an issue with the bypass start relay. Many (maybe all, I'm not sure) of that series tractors have a tricky circuit with a separate relay in the mix, the sole purpose of which is to interrupt the power to the injection pump if/when you "jump" power to the starter solenoid. I don't think I've ever seen that particular feature on any other tractors. I think it may be possible you have an issue with this circuit. I think if it starts, runs, and shuts off with that relay removed, I'd be tempted to just leave it out until you find something else that doesn't work while it's out. I have a diagram for a 5203 tractor that MAY be similar to your tractor in regard to this circuit. Maybe I can pass it on.

file:///C:/Users/user/Downloads/pc%20swap/John%20Deere/5203%20Starting%20System%20(1).pdf

texstrk426 · Dec 30, 2024

When I tried the link you show above, I get a message saying that the file has been removed.

For now, I think I will do just as you said, leave that one relay out and operate the tractor as it starts and runs just fine with that one out. I still plan to check all the fuses just to see if any are blown before I put everything back in place for some work today.

Thanks for your help and suggestions!