John Deere 5210 , tractor stalls when key switch returns to run position

[circle w ranch]

I replaced the fuel shut off selnoid, then the fuel shut off relay, then the small square relays in front of the steering column, and still not working! The crazy thing is that it will start out of the blue and run fine,then go through 5 or 6 start cycles perfect, walk away and come back and its back to same old story. Also replaced the key switch. thanks for the help

 

[DLTTrekkers]

Check your fuses. One might be broken and not blown.

 

[JD5210]

I have attached the wiring diagram and the starting system hopefully this helps.

How I would address this. It is most likely not the problem, but disconnect the cold start advance just to take it out of the picture. When it happens do not touch the key. Then work backwards starting at the fuel solenoid to determine where you do not have power. As already suggested test the 20 amp fuse that is for the fuel solenoid or just replace it.

Write-up from the tech manual.

When key switch (D) is turned to START position, current flows through 30-amp fuse (C), through contacts of key switch and out circuit 571. Current then flows through rear PTO switch (E), circuit 573, and through neutral start switch (G). Current leaving the neutral start switch travels on circuit 301 to both the start (H) and bypass start (I) relays.

Current passing through start relay windings creates a magnetic field, which closes relay contacts. This
connects circuit 002 to 309, providing a current path to the starter S terminal. The starter (K) then cranks the
engine.

At the same time, current travels to the bypass start relay on circuits 301 and 309. Current through circuit
301 creates a magnetic field in the windings of the bypass start relay which pulls its relay blade into contact with terminal 87. Current flow then stops on circuit 309 because of an open circuit between relay terminals 30 and 87A. During normal operation, fuel shut-off relay (L) remains inactive. However, circuits 302 and 092 are connected through normally-closed relay contacts between terminals 30 and 87A. This energizes the fuel shut-off solenoid (M) and allows fuel flow through the fuel injection pump.

 

[Dave M7040]

I note in the full wiring diagram provided by JD5210, the presence of Diode packs in various locations throughout the wiring harness.

JD more than any other brand I know, goes to great lengths to protect their tractors from their owners

My experience in the JD line started with helping the owner of a JD5055D so keep in mind I am not a multi year JD expert.

The diode packs are present, to protect circuits from say a reverse battery jumping.... wrong cable on wrong battery terminal. A charging mistake in the same vein.
This illustration of a relay panel on a similar JD will get you looking for the right thing. i.e. where these diode packs are located.

This is the test procedure:

In the end the problems in the 5055D were related to a temperature sensor of some type. Unplugging the sensor lead removed the problem in the short term.

Dave M7040

 

[Industrial Toys]

I never knew that JD used Diode blocks. From what I see though, they would be used more for Diode Logic than for protection. Let's say you want one circuit to control itself, plus another, but not have that other circuit control the former. Diode logic is cheap and great for that.

But when a diode is blown, it's blown. It would not be inermittant. What you describe could be a Diode (I did not look at the schematics) but would not be intermittant.

 

[Dave M7040]

I never knew that JD used Diode blocks. From what I see though, they would be used more for Diode Logic than for protection. Let's say you want one circuit to control itself, plus another, but not have that other circuit control the former. Diode logic is cheap and great for that.

But when a diode is blown, it's blown. It would not be inermittant. What you describe could be a Diode (I did not look at the schematics) but would not be intermittant.

I agree with your logic in general, but let me add the following.

Within the JD harnesses are "safety" relays. These are not associated say with a seat switch but rather are present to protect electrical circuits from reverse polarity. The diodes are an integral part of their operation. Blocking the relay's action when all is well and switching the safety relay when something is wrong.

The relay part of this overall circuit can be intermittent!

Dave M7040

 

[Industrial Toys]

Not disagreeing, but are you sure that's how jd designed it? I have never heard of such a design. If you do something terribly foolish (and I am one that can't sometimes get the + to+ - to - thing straight in my head, just too complex) I am thinking, protecting your financial wellbeing is the last thing manufacturers seem concerned about. Maybe safety relays, but for reverse protection???

 

[Dave M7040]

Not disagreeing, but are you sure that's how jd designed it? I have never heard of such a design. If you do something terribly foolish (and I am one that can't sometimes get the + to+ - to - thing straight in my head, just too complex) I am thinking, protecting your financial wellbeing is the last thing manufacturers seem concerned about. Maybe safety relays, but for reverse protection???

I am.

I help owners of many brands including the numerous Chinese makes, Kubota, Kioti. John Deere has the most comprehensive manuals. I don't have the time but trust me when I tell you the purpose of the "safety" relays is as I described.

Dave M7040

 

[Industrial Toys]

I will take your word for it. No reason, I shouldn't. I designed and did (Manual) electronic drafting for production equipment (ARPECO Engineering) for pharma back in the early 80s.

Where is Williamstown?

 

[Dave M7040]

Found the JD explanation of the purpose of the safety relays:

If the battery is connected in reverse (positive to ground and negative to power circuits) or the battery was
charged in reverse, positive voltage is provided to both sides of the safety relay coil (100 and 101 Blk wires to
one side; and 100 and 102 Blk wires, V2 diode and 483 Lt Grn wire to the other side). With no voltage
difference across the coil, the coil is not energized and the relay contacts do not close.
If the contacts did close with the battery connected in reverse or the battery charged in reverse, a ground
path would be established through the 575 Red/Blu wire, relay contacts, 480, 403 and 402 Red wires, F2
fuse, 400 Red, key switch, 205 Wht/Red wire, fusiblelink, and starting motor terminal to the battery.

Reversed sensing current would be provided to the voltage regulator/rectifier and damage to it would
occur.


Dave M7040