John Deere 5210 won't stay running

I have a John Deere 5210, 3 cylinder diesel with just over 2000 hours that I bought a couple of years ago. It ran well until last fall. Actually, it still runs well... when it runs.

Here's what I have. I jump up on the tractor, turn the key to Start, and the tractor fires right up. As soon as I let go of the key to Run, the tractor quits... just as if I had turned the key to Off. As long as I hold the key on Start (I know... not a good thing), the tractor continues to run. But here's the catch... once the tractor warms up a little bit, I can let go of the key; let it go to Run, and the tractor continues to run.

It doesn't seem to matter what the ambient temperature is. Once the engine warms up a little, it starts and runs fine.

Other info: I do hear a click at the fuel solenoid when I turn the key from Off to Run.

Can anybody offer some guidance? Thanks!

There are 2 senders located on your thermostat housing, one is for temp, the other goes to the injector pump harness,, unplug the one going to the injector pump, and check the fuse on your circuit board,, the pump sender shorts out and blows the fuse,, you can run it with that sender unpluged it won't hurt anything..

This is my first diesel. Please excuse my ignorance if I name some parts wrong. My "youngest" tractor before this was a 1955 AC-WD45.

I knew there was something I forgot to include in the initial post... I did check all the fuses and they all checked good. Double checked the fuse again this morning just to be sure, disconnected the sensor from the thermostat housing, started the tractor up, and it died as soon as the key went to Run.

There is only one sensor coming out of the thermostat housing (where the upper radiator hose connects to the engine). It has a red wire that goes to a terminal on the fuel solenoid. There is another red wire on that terminal and it heads off in a wiring harness towards the firewall. I suspect it goes to the fuse.

The sensor from the thermostat housing also has an orange wire that goes to, what appears to be, a sensor at the bottom of the fuel injection pump. There is a black wire that comes out of the sensor at the bottom of the fuel injection pump that connects to another terminal on the fuel solenoid. I suspect this is a ground.

Might that "sensor" at the bottom of the fuel injection pump be the V1 diode pack? And could that be the problem? How would I check it?

I hope this makes sense.

Okay... looks like I got a little bit ahead of myself. The tractor started right up when I swapped relays around, so I ordered a new one. Well... I think it was just coincidence that it started that time because when I installed the new relay I still had the same symptoms. So I've spent some time looking a little deeper. Here's what I found.

Turns out this tractor is equipped with a cold start advance. It's not even shown on the wiring diagram I've been working from. Anyhow, from the Stanadyne web site: "By advancing the fuel injection timing during cold engine operation, combustion efficiency is improved and white exhaust smoke is minimized. Once the engine coolant temperature is sufficiently elevated, the injection timing and advance functionality are returned to normal operation." It sounds like that could be an explanation of why the tractor starts and runs fine once the engine warms up. Here's a link to the Stanadyne web page that has a much longer explanation and a diagram of how it works.

http://www.stanadyne.com/dealerportal/ssi/english/Service Bulletin/373A.pdf

I made a drawing of the circuit. I hope it show up here..



How do I test this cold start advance? It's a bit pricey to just swap out... about $100 just for the coil, or a little over $500 for the whole assembly.

Any help would be appreciated.
[img:bb90741de8]http://forums.yesterdaystractors.com/photos/mvphoto16603.jpg

Okay... looks like I got a little bit ahead of myself. The tractor started right up when I swapped relays around so I ordered a new one. Well, I think it was just coincidence that it started that time because when I installed the new relay I still had the same symptoms. So I've spent some time looking a little deeper. Here's what I found.

Turns out the tractor is equipped with a cold start advance. It's not even shown on the wiring diagram I've been working from. Anyhow... from the Stanadyne web site: "By advancing the fuel injection timing during cold engine operation, combustion efficiency is improved and white exhaust smoke is minimized. Once the coolant temperature is sufficiently elevated, the injection timing and advance functionality are returned to normal operation." I think that explains why the tractor starts and runs fine once the engine warms up. Here's a link to the Stanadyne web page. There is a detailed explanation of how this works as well as a nice drawing.

http://www.stanadyne.com/dealerportal/ssi/english/Service Bulletin/373A.pdf

Here's a drawing of the circuit.

How do I check the cold start advance? Swapping parts is a little pricey. The coil for the cold start advance is about $100, and the whole assembly is $500+. Can anyone offer some advice?

(quoted from post at 08:16:44 05/16/18) How do I check the cold start advance? Swapping parts is a little pricey. The coil for the cold start advance is about $100, and the whole assembly is $500+. Can anyone offer some advice?

Click to expand...

The cold start advance is NOT the issue with your tractor "dying".

It's purpose is more for emissions control than as a starting aid.

The sensor (with 2 wires) sometimes fails and blows the fuse that powers it and the fuel solenoid and fuel pump (if so equipped).

If the sensor shorts and blows the fuse, the engine stops, and that's it 'til the fuse is replaced and the cycle then repeats.

If you have done as TimS told you and unplugged the (2 wire) sensor and it starts and later dies, that further proves the cold start has nothing tom do with your problem.

Once again, the "cold start solenoid" MAY help a little with a quicker cold start, but as soon as the engine is running, it does NOTHING but (hopefully) make the exhaust a little cleaner.

Your problem is one of two things, either the fuel shutdown solenoid is "flaky"/thermally sensitive, or something in the electrical circuits of the tractor is cutting power to it.

Try this... connect an unpowered test light between the terminal on the fuel shutdown solenoid and chassis ground, does the light stay on when the engine "dies", orm does it shut off indicating a loss of power?

You can also connect a jumper lead from a 12 Volt source to the fuel cutoff solenoid, and verify that the engine continues to run with as long as the jumper is connected.

If that works, you'll need to figure out where power is being lost in the "run" circuit.

Might be as simple as a failed "ignition" switch that's failing to keep the fuel solenoid energized as the key returns from "START" to "RUN".

Here's what I have. I put the light on the terminal... no light. Turned the key to Run... light. Started the tractor... light. Let the key return to Run... tractor died... no light. Pulled the panels off the tractor and started tracing the wire back to see where the power was coming from. Had power on both sides of the fuse. Went back to the key switch... had power there. Took the switch apart (removed the key part from the wired portion) to see if anything would fall apart. It all looked good. Put it back together and got set up to jumper 12v to the fuel cutoff solenoid. I ran it through a switch so I could apply the 12v as soon as I released the key to Run and the light would go out. Jumped up on the tractor... turned the key to Run... light. Started the tractor... light. Let the key return to Run... light! Tractor continued to run. WTF! Started the tractor about a half-dozen times since then and it continued to run every time. What do you think? The switch? Dirty contacts?

Thank you for your help! I really appreciate it!