JD 4100 Fuel shut off solenoid

[Xjdigger]

My tractor stopped running due to the fuel shut off solenoid is not being powered.

I've been studying the 4100 tech manual and it states
Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 VDC
Pull-in voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.8 VDC
Hold voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0 VDC

I cannot find where this voltage is transformed by the control module.
Is this done internally to the solenoid or does the circuit actually provide 6,8 volts to pull in the pin and hold it with 3.o volts dc.

I've been searching the web on this part #1803es and the only information I find is 12 volt input.

Any help is appreciated.
I can run this until I find the problem by jumping 12 volts to the pull in circuit and holding the shut off open with 12 volts under the assumption that the solenoid it self converts the voltage use.

 

[JD755]

Read my post here.

http://www.tractorbynet.com/forums/john-deere-owning-operating/344528-4110-15-et-al-fuel.html

 

[Xjdigger]

Thanks Jd755
I was reading the post when you replied.
I don't fully understand what you wrote so let me clarify.

You stated that these lower voltages was the minimum operation to pull in or hold through the circuit.

I am assuming that 12 volts is applied to these circuits and the pull in uses 6.8 volts and is held using 3.0 volts. Am I correct

Or is 6.8 volts actually provided to pull in the plunger and another circuit of 3.0 volts provided to hold the plunger in?

By the way I owned a JD850 back in the 80's and replaced it with a 5300 in 97. I needed a smaller tractor and would have had another 750 or 850 but I bought the 4100 because of the mid PTO for lawn mower. I hate computerized equipment so I will be rewiring the 4100 to operate without the automated problems. But I will need to incorporate the safety factors of PTO and drive gear so this stuff will not create an accident if I fail to pay attention. I'm lso building a 64 Chevy 4wd so I won't have another computerized automobile. And I am going to convert my 2004 S-10 with parts from my 92 S-10 so that will not be computerized either.

Thanks for your reply.

 

[JD755]

No, only 12 volts is applied to the coil. It does no voltage conversion, and none is ever required. Those other voltage numbers are just tolerance values. They are used mainly by the manufacturer of the coil for testing purposes to make sure it meets JD specs to work under all typical conditions. Any electrical device has a stated tolerance voltage range over which it is supposed to work. This applies to everything from light bulbs to computers. The coil simply is engaged with 12 volts and disengages with zero volts, plus or minus its stated tolerance.

 

[Xjdigger]

Thanks JD755 and Enjoy

 

[Egon]

You may require a higher voltage/amp draw to open the solenoid than is require to hold it open. Holding the solenoid open with too much amperage may harm it??

There may be a thermistor involved in the circuit which can fail. It may be well hidden within a wiring harness come toon??

 

[JD755]

The hold coil requires very little current. It has nothing to do with actually pulling in the plunger that will allow fuel flow. That is done by the pull-in coil and that does require a lot of current which is why JD uses various methods to shut off current after the engine starts. The hold coil only has to place a pin in position to keep the plunger held and just has to work against a light spring that will pull the pin back when 12v is removed. 12v is on the hold coil continuously until the key is turned off.

 

[Xjdigger]

I just got in from mowing. I hot wired the solenoid and momentarily connected the pull in lead and got the job done with no problems. Now I want to fix this so it is right.

Jd755 you discussed in another thread how you wired your 750, do you have a diagram on how your 750 was wired to have the safety switches operating and not have a failed computer chip controller to deal with?

If I wired the pull in coil to the start cycle of the key switch would there be a problem with winter starting if it cranked to long to over heat the fuel solenoid?

 

[JD755]

My 755 does not have a computer chip. The factory wiring just connects the pull-in coil to the starter motor. No thermistor. No timer circuit. Just a wire to the starter. Never a problem in 22 years.

 

[Xjdigger]

Thanks JD