Strange problem with fuel solenoid

[MichaelOwens]

Many of the solenoids have 3 wires. Ground,pull and hold. When you turn the key higher current pull line is energized and moves the solenoid coil, when the key is released to run pull de energizes and the lower current hold wire keeps the solenoid in position

Thank you very much for the information. Understanding why there are two ground wires is very helpful. I should mention that I have three JD tractors and this problem is with my 4600.

 

[MichaelOwens]

You've already figured out the PULL circuit is bad.. they usually run off of relays located "somewhere".. some have 1 relay & some have 2..
The PULL circuit needs a lot of amps to work & is usually located off the STARTER somewhere.

I think you might be right. I've noticed that only one relay is functioning when I turn the key. This tractor that I'm working on is a JD4600 and the fuses and relays are right below the steering wheel. I'll look around to see if anything is next to the starter.

 

[MichaelOwens]

Sorry about the confusion. This is for my JD4600. I didn't realize this forum would be automatically tied to the tractor I listed on my information page.

 

[gator]

Sorry about the confusion. This is for my JD4600. I didn't realize this forum would be automatically tied to the tractor I listed on my information page.

As Egon mentioned check your thermistor, below are two John Deere solutions about thermistor failure on the 4600 (the second one also talks about oil in the solenoid which you didn't mention but has same failure of thermistor):

Solution Number: 44787

Solution Summary: 4200 4300 4400 4500 4600 CUT Engine cranks but will not start

Publication Date: Jul 17 2002


--------------------------------------------------------------------------------

**Paper copies of solutions may not be the most current solutions**


Complaint or Symptom:

Engine cranks but will not start.

Problem or Situation:

The fuel shut off solenoid pull in winding is not being energized because the thermistor wired into the back of the load center has failed.

Solution:

Replace the thermistor.

Parts:

LVU10323 Thermistor


--------------------------------------------------------------------------------

4200, 4600, 4400, 4300, 4500

also there is this one:

Solution Number: 58414

Solution Summary: Engine spins over but fails to start.

Publication Date: Jun 27 2006


--------------------------------------------------------------------------------

**Paper copies of solutions may not be the most current solutions**

Complaint or Symptom :
The Engine cranks but fails to start. Oil is found in the fuel shutoff solenoid.

Problem or Situation :
It is normal for engine oil to get behind the plunger and the oil should be able to come out before the solenoid pull in winding times out. The R2 thermistor wired behind the K3 relay may not be working correctly causing the pull in winding of the solenoid to drop out to quickly or not pull in at all.

Solution :
Test power going to the white wire on the main harness side of the fuel solenoid. Voltage should be present when the key is initially switched to the run position, but, should drop off after a few seconds. The period of time that the solenoid gets power will change depending on the temperature of the thermistor.

If the 1 second peak amperage draw is less than 20 amps.

Inspect the R2 variable thermistor which is located behind the K3 fuel relay and replace as required with part number LVU10323. This variable thermistor allows the pull in winding of the fuel solenoid to have power initially to be able to pull the solenoid in and allow fuel to flow to the pump. After 1 second this thermistor should drop current flow to the white wire going to the solenoid and keep the solenoid from melting. Peak current flow should be between 20 to 35 Amps during the 1 second time period.

Additional Information :
One Dealer tested current at the thermistor and found that within a few milliseconds the current would only get up to 6 A and then drop off. 6 A will not be enough current to pull in the solenoid in some instances.

 

[Egon]

On my 4200 with no click of the solenoid I apply a heat gun to the solenoid and tap it. Worked so far. I’ve never been able to find the thermistor? Some did not have one.

 

[bjsbobcat]

As Egon mentioned check your thermistor, below are two John Deere solutions about thermistor failure on the 4600 (the second one also talks about oil in the solenoid which you didn't mention but has same failure of thermistor):

Solution Number: 44787

Solution Summary: 4200 4300 4400 4500 4600 CUT Engine cranks but will not start

Publication Date: Jul 17 2002


--------------------------------------------------------------------------------

**Paper copies of solutions may not be the most current solutions**


Complaint or Symptom:

Engine cranks but will not start.

Problem or Situation:

The fuel shut off solenoid pull in winding is not being energized because the thermistor wired into the back of the load center has failed.

Solution:

Replace the thermistor.

Parts:

LVU10323 Thermistor


--------------------------------------------------------------------------------

4200, 4600, 4400, 4300, 4500

also there is this one:

Solution Number: 58414

Solution Summary: Engine spins over but fails to start.

Publication Date: Jun 27 2006


--------------------------------------------------------------------------------

**Paper copies of solutions may not be the most current solutions**

Complaint or Symptom :
The Engine cranks but fails to start. Oil is found in the fuel shutoff solenoid.

Problem or Situation :
It is normal for engine oil to get behind the plunger and the oil should be able to come out before the solenoid pull in winding times out. The R2 thermistor wired behind the K3 relay may not be working correctly causing the pull in winding of the solenoid to drop out to quickly or not pull in at all.

Solution :
Test power going to the white wire on the main harness side of the fuel solenoid. Voltage should be present when the key is initially switched to the run position, but, should drop off after a few seconds. The period of time that the solenoid gets power will change depending on the temperature of the thermistor.

If the 1 second peak amperage draw is less than 20 amps.

Inspect the R2 variable thermistor which is located behind the K3 fuel relay and replace as required with part number LVU10323. This variable thermistor allows the pull in winding of the fuel solenoid to have power initially to be able to pull the solenoid in and allow fuel to flow to the pump. After 1 second this thermistor should drop current flow to the white wire going to the solenoid and keep the solenoid from melting. Peak current flow should be between 20 to 35 Amps during the 1 second time period.

Additional Information :
One Dealer tested current at the thermistor and found that within a few milliseconds the current would only get up to 6 A and then drop off. 6 A will not be enough current to pull in the solenoid in some instances.

I have a 2000 John Deere 4500. new thermister from John Deere. New fuel solenoid from Ebay. Tested solenoid, works as expected. Thermister shows 0ohms with key on. I have no voltage to the white wire on the fuel solenoid. I have 12v to the red wire, the fuel solenoid will hold open (running) if I push in the actuator (removed from the fuel pump) and stay open. My issue is I can't get voltage to th white wire. If I jump a hot wire from the red wire to the white connector on the fuel solenoid, opens right up on its own and holds. How can I test the white wire circuit. I have switched out fuel solenoid relay with the run relay, all relay seam to be working as expxected. it appears to be the fuel solenoid circuit, no voltage on the white wire

 

[thepumpguysc]

It’s my understanding that the WHITE WIRE gets its power (hi amps) from the starter while the engine is turning..(cranking)
Then it’s switched to lower amps to the RED WIRE.

 

[danielolson]

on my 790 there is a time delay control module that's no longer made. You can likely get a thermister kit to do the same function. I narrowed mine down to the module not working and wired a temp switch where i turn the ignition on and then hit the momentary switch to do the pull function and then start.

Switch has to be momentary because of the pull current draw you will destroy the solenoid by leaving it engaged (why i didn't wire directly to the ignition switch)

Added feature, anti theft.

 

[thepumpguysc]

Fantastic idea.!!