2008 John Deere 5103

[cgr]

My tractor didnt start last week and found out had no power to injector pump, so i ran a temporary wire to battery positive post and injector pump and it cranked. i disconnected it and traced red wire from pump to key switch and had power at key switch but would not crank. So as to temporary fix problem, i ran a wire from key switch to injector pump and ran fine. Today it will not start and everytime i turn key switch on it blows 30 amp fuse. Any help would be grateful. Thanks.

[JD5210]

I believe the problem is the thermistor sensor. 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.

You may need to re-prime the fuel system, if it still does not start

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.HomePa geServlet_Alt

URL on the 3029 engine and addresses the cold start
http://www.visaevolution.com/dati_si...5-3029-ENG.pdf

[cgr]

Thanks JD 5210. I will give it a try and get back hopefully with a smile. Thanks Again.

[cgr]

Well i unplugged cold start connection, replaced fuse and its running. It was cold here this morning and it ran rough for a minute and cleared up. Will get new part and change. Thanks again JD5210. This is an awesome forum community. Thanks and God Bless !!!!!

[JD5210]

Glad to hear that this fixed your problem and thanks for letting me know. This does appear to be a common problem with the 3029 engines. On the plus side this is the only problem I have seen on various forums with this engine.

[cgr]

I went to JD to pick up new part and they said to just leave it unhooked. I was kinda shocked. They assured me it will not hurt anything. They saved me a few bucks.

[ScottHertz]

I have to do the same repair. I have the new thermistor but see that changing is a little tight because there is a line going from the fuel pump to the engine that goes right by
the sensor. Any advice on whether, you should take off the fuel line first or is it best to try to replace the part without doing this.
It looks possible not to but very tight.