Kohler ECV870 misfiring

[heavy_kevie]

I ran it for about 2.5 hours today with the O2 sensor disconnected. It seemed to run about normal, 3400 rpm with desk engaged, no load; 3320-3180 while cutting grass. Actual no rpm is around 4300, I've always thought that was too high, maybe I've been running lean all this time. I bought the mower used in November of 2020. Didn't appear to have the best of maintenance performed on it as I found the area around the heads packed with grass.

 

[VegetiveSteam]

Sounds like ignition and fuel pressure are fine. It could simply be a bad O2 sensor. If you could get codes from the ECU that could help.
And apologies if I missed it, but when the issue first started and you felt it was running rich, did you ever notice any black smoke. If so, how do the exhaust manifold gaskets seem? Also, are there any holes in the muffler that shouldn't be there? Even something as small as a missing heat shield screw.

Most heat shield screws don't normally go into the muffler flow area, but I did run into one that did and the little bit of oxygen that hole let in, fooled the O2 sensor into thinking the mixture was lean and that sent a signal to the ECU to richen up the mixture causing the engine to run rich. Once we found the hole and replaced the screw, the engine once again ran as designed. Having never run into that before it was not an easy thing to find. After running into it, if I have an EFI running rich, I check for anything that might let oxygen get to where it isn't supposed to be.

 

[heavy_kevie]

Okay, finally got my test light set up, I have codes 0032 and 0132 set in the ecu. With key on and engine not running, I have 11.7v on pin A of O2 connector (red+black wire), 0v on pin B (green wire), 3.4v on pin C (violet wire), and 0v on pin D (black wire). Resistance between pin D and the negative battery terminal is.01 ohms. With engine running about 5 minutes, voltages on pin A were 13.2, pin B 0v, pin c 0v, and pin D 0v. I didn't check the resistance between the ecu and pins A,B,and C. Is this enough information to say the o2 sensor is bad? I have a little bit of oil leakage around the valve covers, I was thinking about picking up some carb cleaner and spraying around the intake path between the air cleaner outlet and the heads and determine if I have any leaks. I looked around the heat shield and everything appears to be fine.

 

[heavy_kevie]

Okay, finally got my test light set up, I have codes 0032 and 0132 set in the ecu. With key on and engine not running, I have 11.7v on pin A of O2 connector (red+black wire), 0v on pin B (green wire), 3.4v on pin C (violet wire), and 0v on pin D (black wire). Resistance between pin D and the negative battery terminal is.01 ohms. With engine running about 5 minutes, voltages on pin A were 13.2, pin B 0v, pin c 0v, and pin D 0v. I didn't check the resistance between the ecu and pins A,B,and C. Is this enough information to say the o2 sensor is bad? I have a little bit of oil leakage around the valve covers, I was thinking about picking up some carb cleaner and spraying around the intake path between the air cleaner outlet and the heads and determine if I have any leaks. I looked around the heat shield and everything appears to be fine.

Oh, I forgot to add that the manual says 0032 Oxygen Sensor Heater Circuit High and 0132 Oxygen Sensor 1 Circuit High Voltage.

 

[VegetiveSteam]

Oh, I forgot to add that the manual says 0032 Oxygen Sensor Heater Circuit High and 0132 Oxygen Sensor 1 Circuit High Voltage.

Yeah, you likely set those codes when you ran it with the O2 sensor disconnected. Check the manual for the ECU reset procedure to clear those codes. I don't remember that procedure off the top of my head or I'd tell you how to do it. It's pretty simple but needs to be precise. Then run it again with the O2 sensor reconnected and see what codes if any come back. Anytime you disconnect anything connected to the ECU and turn the key on, it will set a code. If you would unplug one of the fuel injectors and turn the key on, it would set a fuel injector code.

If you have any trouble with the reset, reply back and I'll find and post the simplified version I created for new Kohler techs.

 

[VegetiveSteam]

I looked at the ECU reset instruction to refresh my memory and the only thing I did differently was instead of waiting 10 seconds, I would advise techs to wait 15 seconds. The issue I came across one time was, I was on the phone with a tech trying to help him do the reset and when I said to turn the key on/off and wait 10 seconds, he started counting 1...2...3 ect. At the same time, I was watching the second hand on the clock in our office. When he got to 10, our clock had only ticked off 6 seconds. Going more than 10 seconds isn't a problem. Going less than 10 seconds is. I always taught 15 seconds for those who counted to 15 instead of watching a clock.

The reason to wait the 10 seconds is to give the ECU enough time to completely shut down and that takes around 10 seconds. Some ECUs might take 9 seconds, but some might actually take 11 or 12 seconds to completely shut down.

One more thing. A paper clip is just the right size to jump the white and black wires in the 4 pin diagnostic plug connector. Just be sure you don't jump to the red/black wire or dark blue wire.

 

[billbud]

Have a 2016 Dixie Chopper Classic with a Kohler ECV870-3013 and it has an odd issue. It starts fine and runs good for about 2-3 minutes then gets weak RPM drops from 3300 to 26-2800 and exhaust smells rich. Shut it off, restart it and runs good for 2-3 minutes rinse repeat. Check the primary side of the coils from the ecu connector and measures 1.2 ohms starter side and 1.3 ohms oil filter side. Checked the secondary side and measures 77 kohm on starter side coil and 22 kohm on oil filter side. Replaced the coil on the starter side and still have the same indications. Kinda at a loss from here.

 

[billbud]

Have a 2016 Dixie Chopper Classic with a Kohler ECV870-3013 and it has an odd issue. It starts fine and runs good for about 2-3 minutes then gets weak RPM drops from 3300 to 26-2800 and exhaust smells rich. Shut it off, restart it and runs good for 2-3 minutes rinse repeat. Check the primary side of the coils from the ecu connector and measures 1.2 ohms starter side and 1.3 ohms oil filter side. Checked the secondary side and measures 77 kohm on starter side coil and 22 kohm on oil filter side. Replaced the coil on the starter side and still have the same indications. Kinda at a loss from here.

I would check the lifter/ tappet to valve clearance

 

[ILENGINE]

I would check the lifter/ tappet to valve clearance

Hydraulic lifters therefore not clearances to check

 

[VegetiveSteam]

No hydraulic lifters on this one. They are solid. But valve lash isn't the issue.