Lazer Z with Kohler Command Pro 26 EFI

[ILENGINE]

After extensively taking apart every connector, cleaning, etc. here’s what I’m left with:

Felt the ground had a lot of resistance (14-15ohms). Cleaned ground now resistance down to .2. No change.

Tested throttle position sensor. Passed test. Replaced it anyway with another Bosch sensor. Passes test again. Still unchanged. Initialized many times per service manual recommendations. No change.

The mower now runs worse than it ever has. Code 31 is gone, but I now have codes 22 and 23. Code 23 is for faulty ecu/ unable to read ecu data history. I’m not sure how the tps can still be throwing a fault if it passes every test and shows good voltage.

One caviat, the mower does have multiple bad oil leaks, and all grounds, connectors, ecu itself, etc were saturated with either oil or residue. Everything has since been cleaned.

In reference to tigers comment, I’d love to get it to the dealer. But all local dealers refuse to look at it due to its age, stating they no longer have the ability to plug in their diagnostic suite. I have the service manual and am a small engine mechanic myself, however on Atv’s and Powersports, not lawnmowers. I’m in uncharted territory.

I think the TPS is fine. The code 22 is either an issue with the wire, a pin fitment, or is a false flag issue that is a side note for the code 23 which could be related to a wiring issue with the TPS or the ECU is actually going bad.

 

[MParr]

If this engine is original to the mower, it's 20 years old with lots of oil leaks.
How many hours are on the engine?
How is the compression?

 

[slomo]

Codes are JUST suggestions only. A good place to start. Most of the time they are related to the issue. Still start with the basics and carry on.

Verify each part/module/O2 sensor has PROPER battery voltage and a good clean GROUND. THAT is EFI troubleshooting 101.

On cars and trucks, do the same. ABS module codes, verify the ABS module has good power and ground. Then you look at your communications bus making sure you can communicate with the module across said bus. No coms means the module is dead. Replace the ABS module in this scenario.

 

[Zue]

My experience with Kohler Efi has shown fault with fuel pressure every time. Those fuel pumps are pathetic. Especially the after markets ones.

 

[ILENGINE]

My experience with Kohler Efi has shown fault with fuel pressure every time. Those fuel pumps are pathetic. Especially the after markets ones.

And most of those can be traced back to using a fuel filter that has the wrong micron filtration. The pre-filter for the main pressure pump has to be a 10 micron, anything courser will lead to clogging of the internal filter in the pressure pump.