thermo-start issues

[bazman82]

So I am having an issue with the new (to me) tractor not starting in the cold weather.

When the preheating light is on, I am getting power to the thermo-start (using a 12v light tester) but nothing is heating up during the 20-30 seconds that it is on before shutting off. There is electro valve 12v (how its worded in the book, so I assume solenoid) hooked up before the thermo-start. That is also getting power when the light is on (testing with the 12v light tester on the only wire coming off it).

My questions are, is there a way to test the solenoid that I am missing? Electronic troubleshooting isn't really my specialty but I can replace things.... Could the issue be somewhere else, as in, where is the thermostat that tells the computer to use the thermo-start in the first place? How does it know it reached temp? The light that comes on varies in the time that it is on. If it is not to cold then it will only come on for a very short time and when it was below 30 it would come on for about 30 seconds or so before shutting off.

The new thing that happened last night while I tried was that the light came on, went off after 30 seconds and I tried to start, nothing. Then when I turned it on again to try another time the preheat light was blinking. This is the first time that has happened and from what I was googling, a blinking preheating light means a bad thermo-start for some tractors. Not sure if this is the case for all....

Being that parts can be slow to get sometimes for my orphan tractor, I ordered the thermo-start ($180 )from a supplier that usually has Farmtrac or SAME stuff on hand (he did have the part in the warehouse). I have not done a jump test yet, but I am thinking I might before installing the new part. I had the same issue on my old SAME except the thermo-start on it wasn't getting power and with how it was set up, it was easier for me to bypass the original wiring and just hook a separate switch (press and hold type) up to it. I will do the same with the Farmtrac if needed, but I would prefer to have a proper fix in place.

 

[Texasmark]

Fords Thermostart is composed of bypass fuel routed back to the fuel tank from the injectors supplying the combustible. When activated, 12v is available at the only electrical plug on the device....mounted in the intake manifold. 12v causes the coil of wire to glow red and this heat causes a biemetallic, thermally sensitive valve to open and let fuel dribble out........onto the red-orange coil which causes it to ignite. This occurs for 30 seconds or longer depending on temp (operator discretion since it is a manual operation for older tractors) while in the TS position, then the operator rolls the control switch on over to START whereby the voltage is still on the device, keeping the valve open and the coil hot but now you have intake vacuum sucking the "Great Balls of Fire" (Jerry Lee Lewis...singer) into the combustion chamber and igniting the diesel.

On newer tractors, like my Bransons, they use glow plugs on a timer, with no diesel for pre combustion. Yours may use glow plugs on a timer also. I never measured the resistance of a glow plug but to glow red-orange the resistance would have to be very low, approaching one Ohm....an electrical term for resistance that can be measured with a Digital Multi Meter, available lots of places for next to nothing with directions how to use. I have several I bought from Harbor Freight (for 5 bucks) many years ago, keeping them in several places where I need their services.

Since you said you were getting the volts, then the glow plug internal wire may be burned open whereby putting your DMM Ohm meter (function selected) across the hot terminal (one lead) and case (the other lead), (don't have to remove it to make this measurement, just undo the 12v wire) using the lowest Ohm scale....probably 200 Ohms....if good meter will read single digit Ohms, almost like when you touch the leads together on the Ohms scale and read your lead resistance....like 0.4 Ohms on my little HF meters. If you put your leads together and got the reading I mentioned, then put the leads across the glow plug as I said above and the meter doesn't read any resistance...just a blank screen, then the coil in the GP is open and it is defective.

Want more ask!

 

[DwayneB]

Mine doesn't work. I opted for the new Holland water jacket(block) heater since there wasn't a hose to stick a Katz heater in. If you have a good place to install a Katz they are the best way to warm a cold engine for 30 bucks. Assuming you have power close.
My tractor will start in very cold weather with no heat but, it's a lot nicer to plug it up for a couple hours.

 

[bazman82]

Fords Thermostart is composed of bypass fuel routed back to the fuel tank from the injectors supplying the combustible. When activated, 12v is available at the only electrical plug on the device....mounted in the intake manifold. 12v causes the coil of wire to glow red and this heat causes a biemetallic, thermally sensitive valve to open and let fuel dribble out........onto the red-orange coil which causes it to ignite. This occurs for 30 seconds or longer depending on temp (operator discretion since it is a manual operation for older tractors) while in the TS position, then the operator rolls the control switch on over to START whereby the voltage is still on the device, keeping the valve open and the coil hot but now you have intake vacuum sucking the "Great Balls of Fire" (Jerry Lee Lewis...singer) into the combustion chamber and igniting the diesel.
Want more ask!

This is the set-up I have on the Farmtrac. Even though it is 2005, the thermostart is mounted into the intake manifold. It just has a few extra's hooked up to it, I am assuming the extras are only for the light that tells you whens it on and when to start..So for testing the Ohm, the hot terminal is the + on battery and the case you mean on the thermostart where I remove the 12v wire? Or are you talking one lead on the thermostart where the 12v wire was and the other lead somewhere else... My knowledge is limited and terminology is different everywhere so I am usually a picture or hands on guy to learn things I don't know.

 

[bazman82]

Mine doesn't work. I opted for the new Holland water jacket(block) heater since there wasn't a hose to stick a Katz heater in. If you have a good place to install a Katz they are the best way to warm a cold engine for 30 bucks. Assuming you have power close.
My tractor will start in very cold weather with no heat but, it's a lot nicer to plug it up for a couple hours.

I have a Katz magnetic heater. The 300w version. Had it plugged in for 24 hours but didn't really help the actual start of the tractor. I used ether last night to get it going and it just didn't take as long to warm up from having the heater on. I think I would need 2 of them for the size of the tractor...

 

[Texasmark]

Must be like the Ford system in that the Ford has the plug in the back side of the intake manifold, a few inches back from where the inlet hose connects from the air filter. There is an oil line as I mentioned that comes from the injector fuel overflow return line (to the tank) for the fuel part.

Then there is a single blade terminal that gets 12v from whatever kind of energizing circuit being used......no babysitter wire.

If you have an additional wire from the preheat device that may be for your indicator light showing when your energizing device is supplying 12v.

The energizing device could be a simple bi-metallic strip inside some kind of containment that has current flowing through it when you first energize the tractor and then once activated and finishing the time-out preheat period, it opens and a small keep alive current from the ignition switch keeps it from coming back on till you turn the tractor off. In addition to that, there is some kind of ambient temp sensor that is in series with power such that when it's summer time, the preheat doesn't activate. My 6530 has this but the 2400 doesn't....every time I turn the ignition on, cold engine, the light comes on.....it doesn't effect the ability to roll the starter....you can roll it regardless of the light on or off.

You might get your DMM and take some notes in trouble shooting. Process would be write down indications under a set of conditions, pull a wire and note conditions and voltages (and where they are, are not present) kind of thing and come back. A picture of your device showing what's attached to it would help.

Owners manuals usually have schematics of electrical wiring, fuel and hydraulics which would help understand this.

 

[bazman82]

Must be like the Ford system in that the Ford has the plug in the back side of the intake manifold, a few inches back from where the inlet hose connects from the air filter. There is an oil line as I mentioned that comes from the injector fuel overflow return line (to the tank) for the fuel part.

Then there is a single blade terminal that gets 12v from whatever kind of energizing circuit being used......no babysitter wire.

If you have an additional wire from the preheat device that may be for your indicator light showing when your energizing device is supplying 12v.

The energizing device could be a simple bi-metallic strip inside some kind of containment that has current flowing through it when you first energize the tractor and then once activated and finishing the time-out preheat period, it opens and a small keep alive current from the ignition switch keeps it from coming back on till you turn the tractor off. In addition to that, there is some kind of ambient temp sensor that is in series with power such that when it's summer time, the preheat doesn't activate. My 6530 has this but the 2400 doesn't....every time I turn the ignition on, cold engine, the light comes on.....it doesn't effect the ability to roll the starter....you can roll it regardless of the light on or off.

You might get your DMM and take some notes in trouble shooting. Process would be write down indications under a set of conditions, pull a wire and note conditions and voltages (and where they are, are not present) kind of thing and come back. A picture of your device showing what's attached to it would help.

Owners manuals usually have schematics of electrical wiring, fuel and hydraulics which would help understand this.

I was just thinking a picture of the set-up would really help. I replaced the thermo-start last night and since I had the parts on the hand I finally changed out the fuel filter and pre-filter. I tried it out this morning (32F outside) and it still seemed like nothing has changed but it did start. There is only 1 wire coming off the thermo-start and 1 pipe for the fuel. The pipe that connects to the thermo-start goes down to a solenoid and this only has 1 wire coming from it. I assume this controls the fuel flow to the thermo-start and maybe its bad and not activating? The wires from both the solenoid and thermo-start go back to an ECU near the dash from what the manual shows. I will try and get some photos to post tonight of the engine and the manual layout.

 

[bazman82]

This is the layout from the parts manual of how it all looks. I replaced #4 and am thinking #62 may be the next culprit?...

 

[thepumpguysc]

Did u test the "plug" before installing.?? Did u test the old one.?? A simple batter charger will test it.. or some jumpers off the tractor battery.
They have to be left ON for a period of time in order for it to "flame-on"..
You'll actually hear it go "poof"..

Be careful when testing outside the engine.. if its working prop. it'll get red hot pretty quick.
U don't need it to get that hot when testing.. just apply power & when u see it smoke, STOP..

 

[LouNY]

View attachment 629602

This is the layout from the parts manual of how it all looks. I replaced #4 and am thinking #62 may be the next culprit?...

Did you look for fuel delivery when you replaced the igniter#4?
If you remove the line going to it when you activate the system you should have a steady drip or small flow of fuel to the igniter if not no fire no heat no start.