JD 4400 Ser. # 480750 cranks-wont start

   / JD 4400 Ser. # 480750 cranks-wont start #1  

smiddle

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Jan 18, 2012
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Hi, I hope this is the right forum to get an answer to a baffling situation with my 4400 compact tractor, ser. no. above. 3 times in the last month I have shut it down after running for days with no problems and then the next morning it refuses to start. It cranks over fine but wont fire. I have the manual, read about the two coil fuel solenoid valve and how to trouble shoot the system. I have new oil, air, fuel filters, and all fuses and modules in the panel are o.k. I have felt the solenoid valve at the injector pump click in and out so thought the thermistor must be the problem. From a previous post here it indicated the thermistor was behind the fuse panel. The manual is very vague about the actual location. The electrical diaghram shows it to be at the K3 module, wires 85 and 87. Is it really behind the panel or is it contained within the K3 module which is about a 1" cubicle? The only consistency in failing to start is: shut down at night in the shed after a couple days of several starts, fail to crank within a 12 hr. overnight period, try multiple times over 3 days to start with no luck and then for whatever reason it decides to fire up instantly after say, 50 attempts. I would appreciate any experiences, guesses, or thoughts as to this problem and where that thermistor is located. Thanks very much. Steve in Florida
 
   / JD 4400 Ser. # 480750 cranks-wont start #2  
Just a thought; I'm not familiar with a 4400 at all, but I do know that most compact tractor engineers seem to delight in designing operator safety circuits that can drive you nuts. I know some of the New Holland TC series use the seat switch to kill the engine if you leave the seat without the brake set or certain shifters in neutral PTO in off position etc. I know some TCs will crank but not start if the seat switch isn't closed. You may have nothing more than one troublesome connection in your operator present circuit. Check your owners manual to see if you have such a system and what switches are involved
 
   / JD 4400 Ser. # 480750 cranks-wont start
  • Thread Starter
#3  
Hi Harry, Thanks for taking time to reply to the questions. I was gone most of the weekend but this afternoon went ahead and took the fuse panel loose to look behind it. I had to gain some slack in the wiring harness but was able to get it 90* to the tractor. What I found was they soldered on about an 8" pigtail (black and white wires) leaving the back of the K3 module and the thermistor was soldered on to the ends and the whole pigtail in turn had been pushed back into the wiring harness. Maybe this post will help someone in the future who wonders how to get to the thermistor. To me, I haven't found hard evidence in the manual that that's how you go about getting to it. At any rate it seems it could be on a longer pigtail and tucked around the fuse panel so you can get to it from the front. So thanks again for your reply. Best regards, Steve
 
   / JD 4400 Ser. # 480750 cranks-wont start #4  
Dealer replaced my first thermistor and I still couldn't find it.
I did find that if I skinned a bit of the white wire coming from the fuel solenoid I can then momentarily short it to ground when cranking the engine. this gives the solenoid a shot of full voltage without the thermistor in the circuit. With this it has always pulled in and started right up.
If you leave the wire shorted to ground you will burn out the solenoid in a matter of minutes (or less). This happened when I soldered a pigtail onto the white wire to make it easier to ground out and one day that pigtail shorted on its own.....Finally installed a momentary contact pushbutton as an "emergency start".
In my case it seemed to happen when it was cold and only on the first start of the day.
 
   / JD 4400 Ser. # 480750 cranks-wont start
  • Thread Starter
#5  
Hi Pat, Thanks for the info. I appreciate you taking the time to contact me. I am posting back to Larry this morning so you will read what I think is the final outcome of all this. Steve
 
 
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