JD 790 fuel shut off solenoid

[heavyhauler]

my freind borrowed my tractor and he started it up after using it over the weekend, smoke started coming out of the solenoid where the wires come out. OK bought another solenoid and he put it in and the new one got hot and blew the coil windings out the back of the solenoid. I checked the where the solenoid plugs into,of the three wires 2 had 12 volts and the 3rd had 0 volts. trying to figure out what happened, have to spend another $160 for another solenoid.

 

[Tractor Pilot]

Hope this picture from the JD790 service manual helps.

 

[atschirner]

There are two sets of winding in most of these fuel shut off solenoids. One high current for pull in and the other windings to hold it open. It sounds like the 'pull in' winding is staying in circuit and over heating. Look at the circuit that activates pull in. it could be a relay, a thermistor or wired to the starter solenoid to pull in when you turn the key to start. JD uses a number of circuits to achive the same result.

Good luck and please let us know what you find.

 

[heavyhauler]

That helps out alot. I did some checking yesterday with the volt meter, The green/white and white/blue wires have 12.5 volts with the key on, then both drop down to around 9 volts when starting the engine. Any idea's what else I need to look for? I was at work when he put the new one on so I wasn't able to see what he did.
George

 

[atschirner]

Next step would be to get your hands on a tech manual. It will have a very detailed troubleshooting proceedure. From the line drawing it looks like the relay is controlled by the timing module. By following the troubleshooting steps you can isolate the problem before you feed your tractor another solenoid.

Have your searched the TBN forums? I found this link that will get you started:

http://www.tractorbynet.com/forums/...ng/126068-790-fuel-solenoid-fuse-problem.html

 

[heavyhauler]

OK I will go out and check that out. I am in the process of getting a Tech Manual p/n TM1470 on cd with the CTM3 Supplement. I hope this is the right manual.

 

[heavyhauler]

This is what the new solenoid looks like after my friend put it on and why I am trying to figure out what caused it.

 

[Tractor Pilot]

George,

It looks like the TM1470 includes other tractors in addition to the JD790 (670, 770, 870, 970, 1070) and thus is more expensive than getting just the technical manual for only the JD790 (TM2088). Also, you may find a used TM on ebay for cheaper than buying new.

https://techpubs.deere.com/products/ProductSearch.aspx?o=type&type=tm

Bruce

 

[heavyhauler]

Did some checking
1)wht/blk wire from ign switch to fuel shut off relay =12 volts
2)wht/blue from relay to fuel shut off solenoid=12 volts
3)grn/white from relay to fuel shut off solenoid = 12 volts
4)grn/white from relay to time delay control module= 12 volts
5) lt/grn from relay to time delay control module = 8.45 volts

Also I found the TM1470cd manual w/the CTM3 supplement on ebay for $100.00

 

[JD5210]

On the manual you might want to check selectmanual.com TM1470 is $24.95 to download. I have not used this site, but have seen it referenced in other posts.
The other manual CTM3 I found it in this .pdf. Not sure if this is the correct one, but can not hurt to look.

Please let us know what you find.

http://golftechs.us/Manuals/JD220dieselengine.pdf