Strange problem with fuel solenoid

[MichaelOwens]

Hi TBN, I've encountered an unusual problem with my fuel solenoid on my John Deere tractor. My tractor wouldn't start so I pulled the solenoid and it would not retract to let the fuel flow. I was getting power to the solenoid, so I assumed it was bad. I purchased another one and it wound not retract either. I tried it again with another solenoid and all three acted the same. They would not retract on their own, but if you pushed in the plunger with your finger, it would hold the plunger in. When you turn the key off, it would release; but when you turned the key on, it would only hold the plunger in if you push it in manually. There are three wires coming to this solenoid. One is positive and the other two are negative. They all show 12volts of power. The only think I can think of right now is for some reason I'm not getting enough amps to it. The battery turns the starter over just fine, so perhaps it's a loose connection somewhere. Has anyone ever had this problem? Or, do you have any suggestions on what might be causing this problem?
Thank you for any input you have, Mike

 

[DwayneB]

I'd have to see the wiring diagram. My new Holland just has one wire and grounds on the tractor. I'd bet yours is controlled by a computer? If it is it's probably not grounding correctly. I've had lots of problems with circuit grounds on all kinds of stuff. I usually just locate the correct wire and ground it. I'd have to see the schematic but, the third wire might be a signal to another component or back to the computer. My trouble shooting sequence would be to run a wire from the battery to the plus terminal on the solenoid and the ground terminal to the frame and see if it will hold in.

 

[doneill127]

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

 

[thepumpguysc]

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.

 

[Zebrafive]

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

Exactly what I was going to post. You need to figure out why the pull in circuit is not working.

 

[JD5210]

Not saying this is the problem, but I would try and disconnect the cold start advance temp sensor.

Also do your test with a test light. I worked on a 4230 awhile back and the circuit showed 12volts with a meter, but when I put a test light on it, I got nothing. The problem turned out to be a bad connection.

Do not if the 5400 and the 5210 have the same starting system, but I have included a diagram.

 

[thepumpguysc]

WHAT inj. pump is on this machine?? is it the 5400 we're diagnosing?? That has a Delphi fuel system on it & that has a 1 wire solenoid..
If your talking about a Stanadyne inj. pump, that has a 2 wire solenoid & they have a MAJOR PROBLEM w/ the temp sensor shorting out, blowing the start circuit FUSE..
UNPLUG the cold start devise/sensor at the thermo neck & replace the fuse to get started.. then replace the sensor..
IF this is another machine we're diagnosing, please give the mdl..

 

[Egon]

It may be a thermistor in the solenoid opening circuit. Uses more power to open than to hold. The solenoid May engage/disengage the Injection pump rather then shut off the fuel flow.

Thermistor = about ten dollars.

My reference is a JD 4200 series tractor. Three wire solenoid.

 

[MichaelOwens]

Not saying this is the problem, but I would try and disconnect the cold start advance temp sensor.

Also do your test with a test light. I worked on a 4230 awhile back and the circuit showed 12volts with a meter, but when I put a test light on it, I got nothing. The problem turned out to be a bad connection.

Do not if the 5400 and the 5210 have the same starting system, but I have included a diagram.

Thank you very much for the advice. I did have a problem with this in the past and disconnecting it did fix it. Right now, I'm pretty sure I must have a poor connection somewhere and I've been tracking them down and cleaning them up but haven't found it yet.

 

[MichaelOwens]

I wanted to thank you for your help. I've been tracking the wires back into the system and cleaning the connections, but no luck yet.

 

[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.!!