Is that a kohler ecv749 efi? You should be able to read the codes via the MIL. Search for the free service manual. Could be something like faulty oil sensor, or it was fried with 200 amps.

 

Thanks IndyCat for your prompt reply!

Yes, it’s a ECV749-3046 EFI. The MIL light is not lit up when I turn it on 3 times, so I guess there isn't MIL code? It did show at the 3rd time turning to on in the little digital display with "12.3" before it display the hour meter, I think it is the battery voltage, right? I think to read the MIL code I need to count the blinking numbers of the MIL light, but it wasn't lit up at all.

I wonder where is the kill wire for the ignition unit and I would like to disconnect it to try if I could get the spark back. Another thing probably to look is that if there is a burnt relay or so, since I am getting both wire "grounded" constantly when I measuring the two pins to the ignition coil. Any ideas?

Many thanks...

 

Try the flow chart on page 59, read page 58 too.

https://resources.kohler.com/power/kohler/enginesUS/pdf/24_690_02_EN.pdf

 

There is a white wire in the connector between the engine and the mower. If you can disconnect that wire, that disables the machine safeties. When the white wire is grounded, it tells the ECU to kill the engine. There is no ignition kill with the EFI. ECU controls everything, spark, fuel, fuel pump. You should get some flashing from the MIL. Even if there are no codes stored, it should still flash "61". The numbers you mentioned from the coils are Delphi's part number and a manufacturing date code. The coils are fired by the ECU grounding one side of the coil. With the key on, the red w/black stripe should have battery voltage.

 

Many Thanks IndyCat and 65t! I was busy during the week and just got chance to look at it! The first thing I found was the MIL light bulb is bad, I am going to get a replacement for the MIL code.

 

MIL light replaced, however, when follow the instruction to invoke the MIL code by switching ON - OFF - ON - OFF and put the ignition to ON and stay ON, the MIL light stays lit up, no blink at all! By the manual at this time, it should show the error code or if there is no error code, it should blink and show code 61.

Would the above symptoms sufficient to say the ECU is bad? Is there a way to test the ECU?

Any other things that I should try before replacing the ECU? I have never replaced one, any suggestions as how to and precautions?

Thanks in advance...

 

Isolate the engine from the unit. Light staying on can be a symptom of an interlock problem.
The ECU’s i’ve had to replace, which are very very few, the light would not light.
Most got replaced due to spiking during diagnosis by owners.
You have to devise a plan and stick with it.
If you can’t read a wiring diagram, you might be in for a long painful ride.
Even looking at the diagram, you have to isolate the area that concerns you, and forget the noise.

 

Please explain a little bit about the interlock problem, you mean it needs to be reset or so? I could try to understand the diagram, but I don't know where to start looking now.