Help! L3240 won't start when cold

[RoyKing]

So this is sort of a smart circuit in that coolant sensor is involved. So there is no manual on for the heaters?


So you turn key on and wait for the heater light to go out, then turn to start?


So your correct what is the heater light showing, a brief on would indicate temperature sensor, a normal 30 second on would lead to idea that it's the wiring to the ground. I imagine the dash light comes on by the same grounding circuit.

Is the temp sensor an on/off or a real temp gauge?


How about a flat bed scanner, then post them on photo bucket or if this site will allow as attachments, some of pics I've look at seem to have good resolution and are not compressed.


From my experience with Kitamura Japanese wiring methods are little obtuse but that was late 80's machines, manuals had poor English. My Kubota manual for my rtv-x110c has c- rating as far a manuals go, no even close to my Ford truck manuals

 

[bferris01]

Sorry for the delay again.

I did have a second to trouble shoot some more and found, when I ran another ground to the rely, it clicked, activated and was able to start in the cold like normal. So there is something a miss on the ground side that I need to track down.

Only has a short time before back to work, sorry this is becoming a long post.

 

[RoyKing]

So if you don't want to go any further just install a switch on the ground and you've got a manual heater circuit, just don't forget and leave on.

 

[The Fred]

So if you don't want to go any further just install a switch on the ground and you've got a manual heater circuit, just don't forget and leave on.

Yup that'd be like putting a band-aid on your head to fix the sore on your knee, I call that oBamatizing the thing.

 

[RoyKing]

Yup that'd be like putting a band-aid on your head to fix the sore on your knee, I call that oBamatizing the thing.

It makes his tractor useable until he has time or money to continue, Obamatizing would mean he has to pay for even if it doesn't get fixed

 

[bferris01]

I would prefer not to modify it and find/fix the actual problem. Next time I am off shift I will do my best to continue the trouble shooting and wire tracing. Thank you to all for the ideas and help.

 

[crazyal]

From your description it sounds like the computer grounds the circuit to make it work. I think it was Fred who previously said it. If you don't have it I would try to get the wiring diagram to make sure there's nothing between the relay ground and the computer. If not then it's most likely the computer. Without seeing a parts list I don't know if it's a stand alone item or part of the dash. I would expect it to cost upwards of $1000 if you can't fix it. If the glow plug light comes on like you would expect, for some time, then goes out I would think the computer knows it's cold and needs the glow plugs but isn't grounding the circuit. I'm assuming (so I could be wrong) that if the computer detected a fault and disabled the glow plugs you would get a fault of some sort.

Another option would be to do a search for circuit board repair. There's plenty of companies that do repairs to automotive and industrial equipment electronics. You could try to contact one and see what they say. You may need to send them a picture and include the wiring diagram.

 

[The Fred]

How accurate is the engine coolant temperature gauge?

Does the gauge work?

It could be the coolant temp sensor is bad also, that being the input for the glow plug primary circuit.

There is no fault code for the glow plug circuit.

Regards, Fred

 

[moship]

The OP has the temperature sensor values already but uncertain if they were ever tested. The info was provided a couple of weeks ago on the other forum.

Here are the values from the WSM should anyone else need them.

-20C (-4F) 18.89 ohms
40C (104F) 1.136 ohms
100C (212F) 0.1553 ohms

The output is nonlinear so one has to be careful extrapolating outputs at other temperatures.

 

[bferris01]

I am still tracing the ground no luck yet. I have run another ground to the relay and it works fine now until I can find the main cause and the wife will now be able to run it when I am working.

Moship, I did get that info and testing the sensor best I could...I got 1 reading before starting it and another after running the engine a bit, but that was the best I could do/check on my own. I was working in 20-40 degree f, temps at the time. I am hoping to have a friend stop by and do better job with the meter on the sensor soon. Thanks again

Fred,
Yes the senor works like normal, bar graph on the dash as the engine warms up the bars go up, disconnect the sensor and the bar graph goes away. Thanks for all your help.

Thanks again everyone and have a happy and safe Christmas and New Year!

 

[RoyKing]

Since the circuit described a variable resistance thermostat I imagine it also runs the temp gauge, does it seem to be working ok?

 

[moship]

Bferris01,

To test the temperature sensor you'll need to know the exact coolant temperature and resistance value of the sensor. It is best if you can do this at two known temperatures.

Since you're unlikely to have the exact temperatures referenced in the WSM, I've calculated the equation that describes the temperature sensor output at >99% accuracy. Enter the resistance value in Ohms and compare the calculated temperature with the known temperature.

Equation shown below:



If you need help with the equation, just reach out.

 

[crazyal]

If the temp sensor was bad the glow plug light would turn on then go out almost immediately. If it's staying on when the engine is cold as expected then the computer knows the engine is cold and it needs the glow plugs to heat up before starting the engine.

 

[RoyKing]

Since the temp gauge is working there must be another sensor that is configured for a different range. Some one said they sent you the wiring schematics post them and I help you with tracking it down,

 

[moship]

Was the root cause ever discovered and repaired?

 

[bferris01]

HI,

Sorry for the delay (I am one of those furloughed but still have to work, but not getting paid firefighters) so I haven't been on to much working all the time. So I have been unable to find anything with the wires so far. I will keep working on it as I can, thanks.

 

[moship]

Was the root caused ever found?

 

[bferris01]

Was the root caused ever found?

Nope, I just ran a momentary switch in and push and hold for 10 sec and starts.

 

[JWR]

Nope, I just ran a momentary switch in and push and hold for 10 sec and starts.

You talking a manual side path to force the glow plugs on while you hold the button in ?