Confirmation of diagnosis (4200 intermittent start)

[Mighty Dodge]

My 4200 has an intermittent start situation that has become unbearable. I don't here the loud snap of the shut off solenoid. I dug out the thermistor, jumped it, still don't hear the snap of the shut off solenoid. I'm assuming the problem is with the solenoid. Does this sound correct?

thanx John

 

[Egon]

You got company. Mine does the same. I haven't been able to find the thermistor yet.

My temporary solution is a heat gun on the solenoid and pump the primer lever. Then try a start using the pre heaters first. This usually works. Propane torch for heat works too.

I've replaced the solenoid. Now I've got two that work.

I have heard the solenoid will fill up with fuel and not work well??

 

[Mighty Dodge]

Well I'm getting 12v to the shut off solenoid however the voltage doesn't drop while running ( the tractor starts at the moment). Shouldn't the thermistor kick in or out and lower the voltage once running? If so I'm thinking maybe the thermistor failed shorted and fried/partially fried the shut off solenoid. As I said the tractor starts for now but I still don't hear the snap of the shut off solenoid.

Thanx
John

 

[Egon]

Wish I had an answere for you but I've not found the solution yet.

If you pull the solenoid you may find it's good.

 

[CalG]

http://www.tractorbynet.com/forums/...g/101444-fuel-shutoff-solenoid-hows-work.html

I'm not sure if this is the same tractor as yours, but it never hurts to search the forum. No sense beating ones head against a wall that has already been walked around.

I had similar issues with the Hurlimann. The controller is on the blink, It has capacitors embedded in a potted "electronics brick". And those things don't last forever outdoors. "No User Serviceable Parts Inside" ! The unit is quite spendy to purchase and replace.

I'm happy to pull the fuel cut off rod.

 

[Mighty Dodge]

I have searched, the fact that I don't get a loud click from the shutoff solenoid leads me to believe it's not actuating in a sluggish manner. I'll check the safety switches but I thought if one or more is acting up it wouldn't even crank. It cranks but wont start. Today it started right up then later took four attempts but it did start. That's why I think the shutoff solenoid may be sluggish.

 

[CalG]

I have searched, the fact that I don't get a loud click from the shutoff solenoid leads me to believe it's not actuating in a sluggish manner. I'll check the safety switches but I thought if one or more is acting up it wouldn't even crank. It cranks but wont start. Today it started right up then later took four attempts but it did start. That's why I think the shutoff solenoid may be sluggish.

From what I read of the reference post (and my experience with the Hurlimann) The solenoid is OPEN when in the de energized state. That is, fuel can flow when there is NO electricity applied. The time you should hear the "clunk", is when shutting down. When power is removed, the controller circuit APPLIES voltage to the solenoid for several seconds to cut fuel and stop the engine.

IF the Solenoid were "sluggish", and inhibited to move into the unenergized and open position, there would be no fuel flow to start the tractor engine. Also, The engine would not shut down when the key was turned to off when the fuel was allowed to flow.

THis is all a guess on my part. My own issues were with a two wire solenoid that only CLOSED fuel flow when the key was turned to off. BUT The symptoms included both NOT STARTING and Not shutting down.

You could try jumpers from battery hot to see if the solenoid is free to move. Mine worked perfectly when the control module was bypassed. Yours may also.

I considered adding a momentary push button and a couple of wires, but a length of welding filler wire did the same thing and cost nothing ;-)

 

[Egon]

For this type of injection pump the solenoid activates the injection pump plungers.

The Thermister voltage stays the same but the amperage drops. For some a thermistor change has worked. It's only a ten dollar item compared to an almost two hundred dollar solenoid.

 

[texasranger556]

From what I read of the reference post (and my experience with the Hurlimann) The solenoid is OPEN when in the de energized state. That is, fuel can flow when there is NO electricity applied. The time you should hear the "clunk", is when shutting down. When power is removed, the controller circuit APPLIES voltage to the solenoid for several seconds to cut fuel and stop the engine.

IF the Solenoid were "sluggish", and inhibited to move into the unenergized and open position, there would be no fuel flow to start the tractor engine. Also, The engine would not shut down when the key was turned to off when the fuel was allowed to flow.

THis is all a guess on my part. My own issues were with a two wire solenoid that only CLOSED fuel flow when the key was turned to off. BUT The symptoms included both NOT STARTING and Not shutting down.

You could try jumpers from battery hot to see if the solenoid is free to move. Mine worked perfectly when the control module was bypassed. Yours may also.

I considered adding a momentary push button and a couple of wires, but a length of welding filler wire did the same thing and cost nothing ;-)

I've dealt with the system you describe on Massey Ferguson 1200 series. I've not come across a John Deere that works that way though. In the energize to shut off system the solenoid has to open at some point or it would drain the battery. About 10 seconds after you turned off the Massey you'd hear the solenoid release.

 

[Mighty Dodge]

After doing the checks per the service manual, i'm going with a thermistor. Let you know how it works out.