# JD 5303 starting problem



## JCKRBBTJIM

Replaced the battery in my 5303 and now it won't start. It turns over very well but there's no fuel. There is a fuse that blows when I turn the key and I have traced the wires to the top of the fuel pump. What is this electrical part and do I have to replace the whole pump to fix it? Thanks for any and all input.


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## drmonsterbrain

This one is easy! Look above the pump. You will see the coolant temp sensor. In that same area is another similar sensor with a pigtail. This other sensor is called a cold start switch. It is wired with the fuel shut off solenoid on the pump. All you have to do us unplug this sensor and replace fuse. Replace sensor when you can. They aren't expensive.


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## JCKRBBTJIM

It's that simple? That's GREAT news! Thank you very much!


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## drmonsterbrain

Yup! That simple! If you follow the wire from your injection pump's fuel shut off solenoid, you will see where the harness continues to the front of the engine & right to that sensor. I've done tons of them thru the years! Just unplug it! Put one in before cold weather. If u go to your local dealer, a good parts guy won't even have to look it up, it's that common.


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## JCKRBBTJIM

Perfect! We're up and runnin'. Thanks again for your help. I wouldn't have figured that out.


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## drmonsterbrain

Anytime! I know my green machines well! ;-) If you need anything else just holler!


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## CD_Shafer

I've replaced the cold start sensor & checked all my fuses. There is no current going to the fuel pump. Tractor cranks but never fires. I am suspicious of the problem being in the ignition switch, but I'm not sure which wire to test. Any suggestions?


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## CD_Shafer

The tractor is a John Deere 5303.


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## sandy

I realize this is an old post, but I just did what drmosterbrain suggested. Had the same problem with my 5210. Thanks


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## brgordon

I have followed all the suggestions. I can now hear the fuel pump solenoid click on but it still will not start. I used some starter fluid and got it to run once for an hour, but now will not start. Any suggestions?


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## RC Wells

First, lose the starting fluid. This is a modern diesel with a very highly placed top compression ring. This type of engine is not at all tolerant of the explosive nature of starting fluid as it causes the ring to distort and roll into the cylinder when the starting fluid explodes. Do that enough and you will create a starting fluid dependent engine until you have it rebuilt.

To your problem. If the fuel pump solenoid clicks, and you have power to the pump, and the pump still does not run you need to check to see that the diesel line is not pressurized and the pump simply stopped because it is at operating pressure.

If the pump is not stopped because the line is up to pressure, and the pump will not prime the system, you need to pull the pump and have it bench tested. Likely due for replacement.

If you have pressure from the fuel pump to the injection pump, then you need to bleed the injection pump and possibly more than one injector line to clear the air locked condition.


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## 0= Ranch

Just wanted to add my thanks to drmonsterbrain. Out of the blue my 5303 would crank but not start. I called the JD dealer and he suggested I check the fuses and sure enough, one was blown. Replaced it and it blew again when I turned the key on. Found this thread and unplugged the cold start switch and replaced the fuse. Fired right up. Just joined the forum.


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## JB Morace

drmonsterbrain said:


> Anytime! I know my green machines well! ;-) If you need anything else just holler!


I can not get my John Deere 5203 to start, replaced battery, but it will not turn over. Any help appreciated


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## RC Wells

You read the above thread, and check the common items?


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## Firetrucks

I had the same problem. At 503 hours it started in the morning but later in the afternoon it wouldn't. It seemed like a fuel problem so I found the answer here. Unplugging the sensor and replacing the fuse got it running again. I found the best price for the part on Ebay for $50.
Measuring the resistance on the defective part showed a short wire to wire and wire to chassis.
On the new part at 80 degrees, wire to wire was a short and wire to chassis was open. After soaking it in 32 degree water, the measurements were the same.
Attached is the internal view.


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## Jacob Hatfield

I realize this is an old thread but I have a 2006 jd 5203 that I bought at auction 2 years ago only had 240 hrs and the other day I went to start it and it won’t start it will crank strong but no fire so I ohmed out the fuses and they are all fine and checked oil and coolant level and they are fine check all my safety switches and there fine so I unplugged the cold start advanced sensor and cranked it but no fire I traced the fuel all the way to the injector pump and bled it to there when you crank it with the bleeders out on the pump it streams out so I’ve ruled out the pump being bad so I broke the lines on the top of the injectors and cranked it but no fuel I checked voltage on the top of the fuel solenoid and I have 12 to 13 dc bolts when it’s in run position and cranking but I went ahead and run a wire from the battery directly to the fuel solenoid but still no fire you can hear the solenoid click with the key and the wire method please help I’m stumped


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## dburt1583

5303 fuel to the pump, power to the one post on top of the pump, turns over fine. No fuel coming out of the injection lines on the pump. Is there an external fuel solenoid?


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## Tx Jim

dburt1583 said:


> Is there an external fuel solenoid?


Welcome to the TF
Yes inj pump has an electrical fuel control solenoid. Have you checked for a blown fuse?


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## thepumpguysc

No, no external solenoid..
Only 1 under the cover..
The 5000 series has a problem w the temp sensor in the thermostat hsg..
which activates the cold start solenoid on the bottom of the pump..
Unplug that sensor at the thermostat hsg.. replace the fuse..
Loosen the steel lines AT THE INJECTORS and spin the engine until fuel squirts out and tighten..
I hope that helps


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