Kohler Command pro

[mirage]

I have been asked by the county I live in to fix there mosquito sprayer. It has a Kohler ECV630-ECV749 engine on it. This engine is Computer controlled.The problem is the choke is not opening all the way after it warms up and the engine puts out alot of black smoke. The oxygen sensor has been replaced.Did not help. I am in the process of removing the 16 pin plugs out of the computer so I can clean them. That is the first thing the owners manual says to do. My question is if cleaning the Contacts on the computer plugs don't help what should I do next. I don't know how to check the sensor on the choke. I don't know if it is run off of voltage or resistance. Can anyone help me. PLEASE.

 

[thedude74]

Bump

 

[Maintenance Chief]

First off I just want to say I've never messed with the computer control model .
The linkage on most models have a lot of spring tension holes though for various reasons, you might be able to adjust the tension on the choke pull off spring ?

 

[Steve]

I just found this thread as I'm going to bed. If no one chimes in I'll see if I can find a service manual and do some reading tomorrow.

 

[Steve]

Ok, I need some pic of what you are talking about about. With this being EFI it doesn't have a choke. Are you talking about the throttle body? Does this have an electric throttle body or a mechanical governor throttle body?

Here is the service manual that should help you understand a bit better.

https://resources.kohler.com/power/kohler/enginesUS/pdf/24_690_02_EN.pdf?_ga=2.161550399.2011836961.1716383210-1786244915.1716383210

 

[mirage]

I will get some pictures. It does have a Computer on it. You take off the air filter and look ing the throat of the intake and there is a butterfly valve. It stays in the half open position. I have read that if the unit has a Bosch computer on it it is more than likely the computer.

 

[mirage]

The unit has a Delphi computer on it. I have cleaned all of the computer connections and sensor connectors. The engine will run for about two minutes then blow black smoke out of the exhaust. The light on the computer will come on and it is a solid red light. It does not blink at all.

 

[mirage]

Ok, I need some pic of what you are talking about about. With this being EFI it doesn't have a choke. Are you talking about the throttle body? Does this have an electric throttle body or a mechanical governor throttle body?

Here is the service manual that should help you understand a bit better.

https://resources.kohler.com/power/kohler/enginesUS/pdf/24_690_02_EN.pdf?_ga=2.161550399.2011836961.1716383210-1786244915.1716383210

Yes I am talking about the throttlebody. This unit is on a mosquito sprayer with a remote control cable on it. You start the engine let it warm up then turn on sprayer and engine goes to a pre-set RPM.

 

[EFSM]

I have more experience with the Briggs Vanguards with this EFI system, but I think the Kohler should be the same. This has the black Delphi high-pressure fuel pump with a float and needle valve inside, similar to the way a carburetor works. We have seen where the needle valve fails to seal and shoots fuel up the vent tube from the top of the pump into the intake of the engine (that's usually where it is hooked). There should be two fuel lines on the top of the pump (incoming and outgoing) and a vent line. Squeeze the vent line shut and see if the problem goes away.

 

[EFSM]

If that doesn't work, try unhooking the O2 sensor and seeing if the problem goes away. The computer will never go into closed loop with the sensor unplugged. If you're dealing with some other sensor that's bad it could be throwing things off when it goes into closed loop (running with live data from the O2 sensor).

 

[mirage]

yes when you disconnect the O2 sensor it goes away. There is a new O2 sensor installed. I forgot how to get the codes but just remembered.It is throwing a 10 then 2 then 2 then 3 then back to 10.Going to see if the service manual will help. Thank you for all the help. PS I have taken some motorcycle jumper cables and jump them from the - side of battery to the engine. No better

 

[EFSM]

OK so there is another sensor that is giving a faulty reading--I would guess it is the engine temperature sensor telling the engine it is really cold so that it gives way more fuel. Unless it's a defective O2 sensor. They can be pretty fragile.

 

[mirage]

I just reset the Computer. I ran great for about 2 minutes, then stumbled and started smoking again. The lights on the Computer are solid red no flashing. I will try cleaning plugs and oxygen sensor and reset the computer and see what happens.

 

[nbbt]

For checking for sensors functionality, the temp sensor should have a base resistance (1k to 100k depending on the sensors specs) across both wires (unplugged) when at ambient (cold engine) temp and vary going up or down when warming up. If you have a temp gun use that to see what the temp range is where the sensor attaches, and then use an appropriate heat source on the sensor to see if sensors resistance changes out of circuit. It should move fairly quickly when the temp gets within 20-40 degrees of what you measured after warm up.

The O2 sensor should have a voltage across the terminal. of 0-1.2, 5, and possibly as high as 12VDC (not very likely). See if the voltage changes when warming up. Add thin wires into the connector to use as voltage testing points to take this measurement. If possible use 2 voltage meters on the O2 sensor one lead to gnd and one to each of the test points.

Best way to see if one is defective.

 

[mirage]

Thank you nbbt for taking the time for this wright up. I got in touch with a factory tech guy and he was able to give me some info on this. I looks like the owners of this mosquito sprayer, apparently put the wrong oxygen sensor in the muffler. The deck was able to run the build sheet on the unit and the part # do not match.I order a factory sensor and will install it when it comes in. Will let you guys know. Thanks for all the help.

 

[mirage]

Ok after talking with the factory again they asked me if the 02 sensor was a Kohler part. After checking the sensor it was factory. They asked for the part # stamped on it. The part # was not what the correct number. I did not order the part the county did. So after a couple resets and the right 02 sensor I seams to run good. The county says it runs ruff at idle. I will be replacing the plugs in it. I should have done that when I replace the sensor but it is a 50 mile round trip to town. I want to say that Kelly at the factory was a GREAT guy to deal with. Wish everyone was like that. We will see if it makes it through mosquito season.