Kohler ECV870 misfiring

[heavy_kevie]

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.

 

[Tiger Small Engine]

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.

Never heard of that Kohler model number (double check if correct). What made you use a multimeter to check ignition coils? Did you take them off of mower to check? Did you pull kill wires or spark plug boots to coils and plugs to see if any change in power? Sounds more like choke on carburetor is not functioning correctly? Do you have black smoke from muffler? Have you pulled the spark plugs to check condition of plugs?

 

[ILENGINE]

Do you have a MIL light on when this happens. That would give some direction to the problem. But sounds like the issue starts when it goes into closed loop. Disconnect the O2 sensor and then start it and see what happens.

 

[heavy_kevie]

Unfortunately no MIL light, the engine model number is for the Kohler 31hp fuel injected engine used on Dixie Chopper lawn mowers so there is no choke or carburetor. The primary side was checked from the ECU connector terminals through the coil with a DVM. The coil supports a dual spark plug design and were checked on the secondary side from one boot terminal to the other boot terminal with a DVM. Did not pull kill wire nor pull spark plugs as I believe I am not getting spark steady for some reason and the exhaust smells rich. Spark plugs are platinum and were installed two years ago. I may be able to use my DVM to simulate the MIL light if I can find the 6 wire connector that Kohler uses to power the MIL.

 

[heavy_kevie]

Data from the engine tag: Serial 4509700131; SPEC PS-ECV870-3013

 

[VegetiveSteam]

Do you see any black smoke when you feel it's running rich? Lean exhaust also stinks and burns eyes but there wouldn't be any black smoke.

And like ILENGINE mentioned. Try running it with the O2 sensor disconnected. If it runs better don't automatically think you need a new O2 sensor. You might need one, but there are other things that influence the O2 sensor so some other testing will be needed.

Are there any lights that come on when you turn the key to the start position? Key on, engine off.

My main question would be, do you see any black smoke?

 

[heavy_kevie]

Tried to hook up my DVM to the MIL output terminal (pins 3 and 4 on 6 wire connector) but it doesn't respond quick enough to capture the voltage change. Ran engine at 2600rpm for 4 minutes, started missing but no black smoke. Disconnected o2 sensor and ran at 2600 for 4 minutes, no miss detected, ran at 3600 for 2 minutes, still no miss detected. Does that mean it is running okay in open loop but the miss appears when it is running in closed loop?

 

[VegetiveSteam]

Have you tried actually using the equipment with the O2 sensor disconnected? My guess is it will lack power as I believe it might actually be running lean.

To make a MIL, you'll need a test light with an incandescent bulb, not an LED. Clip it to the positive terminal of the battery and probe the backside of the tan wire 3 in the engine to equipment connector S. You just made a MIL light. The link below should take you to the Kohler Service Manual which might be nice to have.

If you could test the fuel pressure that could answer a lot.

https://resources.kohler.com/power/kohler/enginesUS/pdf/19_690_01_EN.pdf

 

[heavy_kevie]

Yes, I ran it with the O2 sensor disconnected, that was in my previous post. It seemed to run fine with the o2 sensor disconnected. And thank-you for the download link, I'll get that right now. I'll see about getting a small incandescent light tomorrow. I have an old pressure gage but it only goes up to 20lbs.

 

[VegetiveSteam]

Yes, I ran it with the O2 sensor disconnected, that was in my previous post. It seemed to run fine with the o2 sensor disconnected. And thank-you for the download link, I'll get that right now. I'll see about getting a small incandescent light tomorrow. I have an old pressure gage but it only goes up to 20lbs.

It was in your previous post that you ran the engine. I was trying to ask if you actually tried using the equipment? Make it do work so the engine has to carry a load.