Kohler ECV870 misfiring

[TobyU]

A classic example of making something over complicated that didn't need to be that way.
We turn these mowers into a complicated bi-directional computer system a fuel management etc which makes them far harder to troubleshoot and makes the parts far more expensive and more of them.
I'll pass.

I will admit I really wouldn't want to go back to carburetors on cars because fuel injection is just so convenient and near perfect and consistent... But for lawn mowers, I need nothing more than a carburetor.
I will be driving one of my car toys tomorrow that has a Holley carburetor on it though.
It is almost as perfect and consistent as fuel injection and I used to have a 67 Pontiac with a 750 double pumper that was the best starting, running, carbureted engine I've ever had so in that case who cares about fuel injection!

 

[VegetiveSteam]

For the average do-it-yourselfer, no question, EFI engines are harder to troubleshoot sometimes.

The issues I would often run into trying to help techs troubleshoot EFI engines is, they seem to forget it's an engine. An engine comes in their shop lacking power and they immediately want to blame the EFI system. They spend hours swapping parts with no success only to later discover the engine is low on compression due to leaking valves or just plain worn out. They forget to start with the basics.

Give me a fuel pressure tester and the diagnostic program and I'll take working on an EFI engine over a carbureted engine anytime.

I'll admit I'm not very smart so having the ability to connect an engine to a diagnostic program that when used correctly will pretty much tell me what if anything is wrong with the EFI system is great for me.

 

[heavy_kevie]

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.

Okay, got the o2 sensor plugged back in and the ecu reset, fired it up ran good for 6-7 minutes then started misfiring. Hooked up my light to check for codes and no codes set, just the end message of 61. Also, didn't get a chance to do the tps learn procedure due to the misfiring.

 

[VegetiveSteam]

Okay, got the o2 sensor plugged back in and the ecu reset, fired it up ran good for 6-7 minutes then started misfiring. Hooked up my light to check for codes and no codes set, just the end message of 61. Also, didn't get a chance to do the tps learn procedure due to the misfiring.

It's good to do the TPS learn but not the end of the world if you don't.


Any chance you could post a short video of it when it's misfiring?

 

[heavy_kevie]

Okay, I've got the file compressed in the mp4 format to 3.3MB, but it says the file is too large. What do I do now?

 

[heavy_kevie]

I think I finally got it. Compressed the file further and converted to zip file. Temp while recording was 68F, 42% humidity, 29.89 barometric pressure. Engine had been running for 5 minutes.

 

[VegetiveSteam]

I think I finally got it. Compressed the file further and converted to zip file. Temp while recording was 68F, 42% humidity, 29.89 barometric pressure. Engine had been running for 5 minutes.

Was it acting up? Unfortunately, I didn't catch anything that sounded all that unusual. Does it still smell like it's running rich? And sorry if I missed your answer to this but have you ever seen any black smoke from the exhaust?

I also thought of another test involving the O2 sensor but it's been a while since I've run tests without the diagnostic program. It involves a test with a voltmeter and what the service manual shows I believe is incorrect. I want to run it by someone first to make sure I'm correct before I have you waste time with it. He's one of the best with Kohler EFI and he will know immediately if the manual is accurate.

 

[heavy_kevie]

Was it acting up? Unfortunately, I didn't catch anything that sounded all that unusual. Does it still smell like it's running rich? And sorry if I missed your answer to this but have you ever seen any black smoke from the exhaust?

I also thought of another test involving the O2 sensor but it's been a while since I've run tests without the diagnostic program. It involves a test with a voltmeter and what the service manual shows I believe is incorrect. I want to run it by someone first to make sure I'm correct before I have you waste time with it. He's one of the best with Kohler EFI and he will know immediately if the manual is accurate.

Yes, it was misfiring as you can see from the rpm display. Typically it would idle 1500-1550 rpm but as the video shows it dropped to the 1300's, and when the deck is engaged with the mower setting still it typically runs between 3300-3400 rpm but with the o2 connected it was dropping down to 2800 rpm. I did not notice any black smoke when it started misfiring and the smell was more acrid rather than rich.

 

[VegetiveSteam]

I spoke with my EFI person and in describing your issue he's 99% sure you have a bad O2 sensor. There is a test you could do but it involves probing through the insulation on the black and purple O2 sensor wires. It really won't hurt anything if you're replacing the O2 sensor but if not, you'd want to seal up the holes you made with some sealant.

We wouldn't do this type of test very often but when we did, we would either use a straight pin or a small pointed meter probe. You'd be measuring DC voltage with a voltmeter. The O2 sensor puts out between 0 and 1 volt DC. The sensor will put out closer to 1 volt when it senses less oxygen in the exhaust or rich. Maybe something like .8 or .9 volts. You'd want to test the voltage after the engine warms up and goes into closed-loop.

More oxygen or a lean condition will give a lower voltage reading closer to 0 volts. Maybe something like .1 or .2 volts. It appears your issue is a lean condition which should result in a low voltage reading but, if the O2 sensor is faulty you are probably going to read something closer to 1 volt. That would fool the ECU into thinking the mixture was rich and lean it out causing the issue.

If you do decide to pin the wires, make sure you don't pin the red/black wire. That is battery voltage for the O2 heater. The purple wire is the DC voltage created by the O2 sensor and is being sent back to the ECU. The black wire is the ground for that circuit.

I hope this helps.

 

[cliffeby]

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.

It sounds like a condenser issue on an old points type ignition system. I don’t see it in your diagram but does the ignition system have an ignition capacitor? I replaced mine two times before I got one that didn’t fail after a few minutes.