Help! L3240 won't start when cold

[firebird93]

i had a 3240 that did the exact same thing. the glow plug indicator on the dash would come on and cycle as it should. the relay clicked and passed power as it should. all plugs and connections were tight and looked good. but no power at the glow plugs. i used a simple 12volt test light and it took me hours to find it but it was a plug on the wire going to the glow plugs right at the relay. repaired that and no more issues.

 

[bferris01]

i had a 3240 that did the exact same thing. the glow plug indicator on the dash would come on and cycle as it should. the relay clicked and passed power as it should. all plugs and connections were tight and looked good. but no power at the glow plugs. i used a simple 12volt test light and it took me hours to find it but it was a plug on the wire going to the glow plugs right at the relay. repaired that and no more issues.

Thank, I am running out of things I can check, I am going to have to try and get a buddy over with more skills than I have.

 

[bferris01]

i had a 3240 that did the exact same thing. the glow plug indicator on the dash would come on and cycle as it should. the relay clicked and passed power as it should. all plugs and connections were tight and looked good. but no power at the glow plugs. i used a simple 12volt test light and it took me hours to find it but it was a plug on the wire going to the glow plugs right at the relay. repaired that and no more issues.

How did you get the socket off the bar that is is attached to in the dash? I moved the cluster but can seem to get it loose to double check it. I tried a small screw driver but it didn't release. Any tricks?

 

[pepper66]

Bferris.
From the picture of the relay I could only tell you how it works. I can't clearly see the terminal numbers, but I can tell by the terminal blade sizes. The large blades carry the current from power to the glow plugs. Power may be battery+ or switched ignition. I would say probably battery + or always hot. The smaller terminals energize the relay. I'm not sure how a Kubota operates without looking at a wiring diagram. On an auto one of the small blades would be ignition + and the module or dash cluster in our case would complete the circuit. I can look at the wiring diagram on my M59 tomorrow, it may be similar. I don't think the power to the large blades would go through the ignition switch, that is probably too much current for the switch.

 

[firebird93]

How did you get the socket off the bar that is is attached to in the dash? I moved the cluster but can seem to get it loose to double check it. I tried a small screw driver but it didn't release. Any tricks?

sorry i don't remember the details. that was 2 tractors ago. i just remember it was in the dash behind cluster and what i finally discovered
i wish you best of luck. i know it can be frustrating.

 

[pepper66]

Bferris
I looked at M59 wiring diagram. Your relay is in the same location as mine, look like a similar setup except my instrument cluster is on the right rear fender. The large blades, one to glow plugs, the other to battery + 12 volts all the time. The two small blades, one is hot 12 volts with ignition on. The other goes to the cluster and supplies the ground or - to the relay this completes the circuit and allows the relay coil to energize. Dont not connect anything this wire to test it, except a high impedance voltmeter. The circuit from cluster to relay is a very low current circuit. If you can fell the relay click

 

[pepper66]

If you can feel the relay click when you turn ignition on the cluster circuit is ok.

 

[bferris01]

Thank everyone, I am back to work at the firehouse for next 48 hours, so I won't have chance to trouble shoot it again for a bit. I will update what I find, thanks for all the thoughts.

 

[moship]

The pin numbering scheme for the relay from the Grand L40-3 WSM is shown in the first picture.

2nd Picture:
I've also included a picture of a Glow Plug wire connector above the oil filter area that is an easy location to check the presence of battery voltage. Simply disconnect to remove the Glow plugs from the circuit, so the voltage can be tested. (The OP also has this problem posted on another forum and he doesn't have this connector. I'm including the info in the event it helps anyone else that may have this connector. Perhaps the difference is that I have a cab model (L4740-3) and the OP is ROPS. It's also near impossible to isolate the glow plug power supply at the buss bar because of the AC compressor and bracketry being in the way. The voltage can NOT be measured with the glow plugs in the circuit.)

3rd Picture:
The last picture is of the 50 amp slow burn fuse for the Glow Plug power feed (Relay Pin 1). This wire then runs to the relay and from the relay Pin 3 to the Glow plug.

If nothing else, this may help others.

 

[RoyKing]

if jumping the relays delivers power to the glow plugs that side of circuit is ok, that leaves mainly the relay and it's primary circuit. So make sure the relay is the right amperage and test primary side with bulb to verify the ground side good. Compare the bulb brightness when connected to known good ground as compared to the ground in the relay block. Cause sounds like you have tested everything except the ground circuit in the relay block.

 

[bferris01]

Hi Everyone,

Sorry I had to work 6 out of 7 days straight this week and that is 24 hour shifts, so I didn't have chance until today to get back.

I am unable to find any breaks in the wire so far.

I did make some "extender wires" with male and female spades to get the replay up out of the dash. Put male side in the relay socket and the female on the corresponding relay terminal so I could test.

Now that it is away from the other relay and I testing it with a meter, I am getting all the proper voltage to the relay (12V on terminal #1 always, 12volt on #2 with the key on.

But the relay is not clicking and passing 12 volt to terminal 3 like the other is. ( I tried all 3 relays I have an all act the same way. Also when I bench test them they click strong enough I can feel it )

Does anyone know if terminal 4 is just a ground or what it goes too?

I feel like something is not telling the relay that it is ok to activate and let the power through, maybe?????????

I don't know if any of that makes sense.....sorry.

I guess I will have to get it to the dealer somehow.

 

[RoyKing]

From what you have describe you very close to figuring it out. So you got battery hot large terminal in , glow plugs large terminal out, you show plus 12v when you the key is on, and when glow plug on position half way to start, are you sure your hold the ignition in heat position and dash is showing the glow plug indicator right ? Now if the relay won't close it is the ground circuit through the ignition switch, verify with one more jumper from ground leg on the relay to known good ground it should fire the relay.

 

[pepper66]

Terminal four is the ground that completes the relay coil circuit. I'm not sure if it goes through the ignition switch,or the instrument cluster. Maybe someone with a WSM could tell you. Don't ground that wire while it is connected to the tractor wiring. Leave it connected to the relay but disconnect from the connector side.

 

[RoyKing]

That's a good precaution. Then a way to verify it's bad use a bulb from battery to socket ground and turn key to heater and see if lights.

 

[The Fred]

At this point you might seek a little dealer or technical help. The wire that goes to the instrument cluster is the one that grounds the primary side of the glow plug relay.

If you put power to this side of the circuit chances are you will screw up the cluster itself as it most likely being 80s Jap technology isn't designed to withstand the current you apply.

Good luck, Fred

 

[RoyKing]

At this point you might seek a little dealer or technical help. The wire that goes to the instrument cluster is the one that grounds the primary side of the glow plug relay.

If you put power to this side of the circuit chances are you will screw up the cluster itself as it most likely being 80s Jap technology isn't designed to withstand the current you apply.

Good luck, Fred

He is not putting any power into the cluster by grounding the relay to a known ground. He is bypassing the cut on side of the circuit. Since I don't have that model of tractor wiring diagram in front of me let me ask this question is this a manual heater circuit ? meaning do you have to hold the key between the on position and start for heater circuit to come on. Or is it an auto circuit that comes on when you turn the key to on and runs for 30 seconds.

 

[moship]

Pin 4 of the Glow Plug Relay is the ground side that goes back to the instrument panel. This is Pin 11 on the 20 pin connector on the instrument panel cluster. The OP can check continuity between the two ends (Pin 4 of relay and Pin 11 of connector). Should also check to make certain the pins are fully seated within their socket and verify there is no corrosion.

If all this checks out, it could be the coolant temperature sensor is not sending the correct ohm value with respect to temperature. IE: The computer thinks it is warmer than it really is.


I'm fairly certain I posted the info from the WSM on testing the coolant sensor, but it could be on the other forum the OP has been duplicating his efforts on.

 

[Reg]

Glow plugs DO deteriorate.
I went through the phases from harder starting when cold to harder starting when cool to wouldn't start unless the block heater had been plugged in for two hours if below freezing.

In retrospect I wasted a LOT of time, money and knuckle skin on lower hose and block heaters - - time money and effort that would have been better spent on troubleshooting the glow plugs themselves, which I had to do eventually anyway.

By the time I unhooked them so that I could meter them individually three were open circuit and one was 38 Ohms.


So, my recommendation is that you remove the wiring from each glow plug right at the glow plug, then meter the resistance of that glow plug to the engine block.
Anything over an Ohm or two is a BAD plug.
If this problem is new this season you likely only have ONE that is bad, but any that read significantly higher than the lowest two - - are at least "suspect".

 

[The Fred]

Glow plugs DO deteriorate.
I went through the phases from harder starting when cold to harder starting when cool to wouldn't start unless the block heater had been plugged in for two hours if below freezing.

In retrospect I wasted a LOT of time, money and knuckle skin on lower hose and block heaters - - time money and effort that would have been better spent on troubleshooting the glow plugs themselves, which I had to do eventually anyway.

By the time I unhooked them so that I could meter them individually three were open circuit and one was 38 Ohms.


So, my recommendation is that you remove the wiring from each glow plug right at the glow plug, then meter the resistance of that glow plug to the engine block.
Anything over an Ohm or two is a BAD plug.
If this problem is new this season you likely only have ONE that is bad, but any that read significantly higher than the lowest two - - are at least "suspect".

He's already proven the relay is not turning on so it's a moot point. I offered him the complete WSM for his machine but it's too large for email. That's why I asked him if he Skyped.

There is a whole troubleshooting process for the relay primary circuit.

Regards, Fred

 

[crazyal]

Do you want to fix it back to the way it left the factory (including the cost) or would you be fine with making a small modification? I think what I would do is just make it manual by removing the computer out of the system. You could simply add a push button style switch to activate the relay. It would be real cheap. You would even have a light on the dash to tell you how long to hold the button in for. Another option would be to add a block heater. My relay died and I didn't know because with the block heater the engine would start up anyway. If you know someone who knows electronics they could probably trace it down to the exact component that's bad. As for the water sensor vs the control board, does the yellow light stay on for a long time or does it shut right off? If it's staying on then the tractor knows it's cold and the glow plugs need to be on for longer.

For example years ago my oven died. It was just a year out of warranty. The heating element for the oven wasn't coming on. With a multi-meter I found that a $2 relay on the main control board was bad. The new board was something like $400 and it had already burnt up two heating elements so I wasn't about to give Maytag any more money. Chances are that there's a small relay soldered onto a board that closes to activate the larger relay. With some skills the dash could be troubleshot (assuming that you can get at the circuit board).