Kohler EFI engine swap in Deere LX173 wiring question...

MJM48 said:

Will,
I used a test light and yes it followed the 3 steps you listed above. At the risk of jumping ahead of your thinking as I studied the wiring diagram for the Kohler EFI with your insight I have the following 4 questions.
1. Should the Deere white wire #940 (which is part of the fuel shut-off system) be wired to the Kohler 6 pin connector in the #4 pin location. As I read the diagram it appears this Kohler red/black wire powers the ignition coils and the fuel pump.
2. Should the Deere yellow/black wire #416 (carb solenoid fuel shut-off ) be tied into the same Kohler pin as above (#4 in the 6 pin connector that powers ignition coils and fuel pump) this would in affect be the fuel pump shut-off.
3. Where should the Deere red wire #205 go? This #205 red wire was part of the original 4 pin connector to the old CV15 engine. Based on my limited understanding from your first post this appears to also be part of the fuel shut-off system. If questions 1,2, and 3 are correct this would make 3 Deere wires, (white #940; yellow/black #416 and red 205 all connected to the Kohler #4 pin in the 6 pin connector.
4. The Kohler #2 pin, white wire which connects to the Diagnostic Connector is shown connecting into the #14 pin in the Grey Connector on the ECU (2 pages before the wiring diagram I attached). The number 14 pin is titled, "Safety Switch Ground." Should I attach a ground in the Deere 6 pin connector to complete the Kohler 6 pin connector wiring?
I hope these 4 questions haven't muddied the water.

I had some time today but will not be able to do further tests/work until Friday. Thank you again so much for your time and insight.
Mike

Click to expand...

Mike,
I checked out those wires. I will list my answers 1-4 below in the same order as your questions above.

1. The 940 wire is a ground that was used to kill the ignition coils on the old system and works with the safety system. See answer #4 below.

2. The 416 wire is your switched power and works with the safety system. I would put the 416 wire in the #4 spot on the 6 pin connector as that is the ignition switch wire. After doing that, make sure the safety system will shut the engine down. If it doesnt for some reason, we may have to figure something else out.

3. The 205 wire was your B+ wire for the old voltage regulator, which, on the EFI diagram, is the purple wire labeled 'H' off the regulator labeled 'O'. Since the EFI purple wire is connected to the red wire going to your battery, I'm going to say we don't need to connect this 205 wire. In short, the 205 wire is being replaced by the purple wire on the EFI system. Once we get everything up and running, we will do a voltage check at the battery. And if the system is putting charge into the battery, which it should, then we won't need the 205 wire.

4. The #2 spot may be where we want to connect that 940 ground wire. If I read this right, this terminal is for a ground that would be part of the safety system, meaning that we would only want it to ground out by a safety switch. So that would match up with our 940 wire.

When connecting up the wires, just make temporary connections until we make sure everything is going to work as it should, then trim the wires and route them to make it look nice.
Let me know how you make out.

Will

Will1988 said:

Mike,
I checked out those wires. I will list my answers 1-4 below in the same order as your questions above.

1. The 940 wire is a ground that was used to kill the ignition coils on the old system and works with the safety system. See answer #4 below.

2. The 416 wire is your switched power and works with the safety system. I would put the 416 wire in the #4 spot on the 6 pin connector as that is the ignition switch wire. After doing that, make sure the safety system will shut the engine down. If it doesnt for some reason, we may have to figure something else out.

3. The 205 wire was your B+ wire for the old voltage regulator, which, on the EFI diagram, is the purple wire labeled 'H' off the regulator labeled 'O'. Since the EFI purple wire is connected to the red wire going to your battery, I'm going to say we don't need to connect this 205 wire. In short, the 205 wire is being replaced by the purple wire on the EFI system. Once we get everything up and running, we will do a voltage check at the battery. And if the system is putting charge into the battery, which it should, then we won't need the 205 wire.

4. The #2 spot may be where we want to connect that 940 ground wire. If I read this right, this terminal is for a ground that would be part of the safety system, meaning that we would only want it to ground out by a safety switch. So that would match up with our 940 wire.

When connecting up the wires, just make temporary connections until we make sure everything is going to work as it should, then trim the wires and route them to make it look nice.
Let me know how you make out.

Will

Click to expand...

Hi Will,

No luck. I did notice that the yellow/black wire should be #416 not #415- both 415 and 416 are yellow/black wires. I'll list what I've currently got set-up. I have put the Deere wire in pins that mate with the Kohler 6 pin connector. I have also attached the print out of the ECU pin configuration.
Deere side connector:
Pin #1- empty (empty on the Kohler side)
Pin #2- white wire #940 [According to LX173 Electrical Schematic, pg 5-13 went to "A1 Ignition Module."]
Pin #3- new wire (red small gauge to match Kohler gauge) to MIL on dash- I have checked to make sure on correct polarity of Malfunction Lamp.
Pin #4- yellow/black wire #416 [on the Deere schematic went to "Y1 Fuel Shutoff Solenoid"]
Pin #5- tan wire # 620 [on the Deere schematic went to "B1 Engine Oil Pressure Switch/light"]
pin #6- purple/white #721 [on the Deere schematic went to "M1 Starting Motor"]

Kohler Engine side 6 pin connector:
Pin #1- empty
Pin #2- white wire [goes to grey connector on the ECU which is called, "Safety Switch Ground"]
Pin #3- black MIL [goes to MIL]
Pin #4- red/white [goes to black connector on the ECU called, "Ignition Switch (Switched +12V)]
Pin #5- green [goes to "Oil Pressure Switch"- no pressure switch on engine. I have the old one and when I change the break in oil at 25 hours may try to install in provided port.]
Pin #6- dark blue [goes to "Starter Motor"]

I have run the following test lamp check this was performed on the back of Kohler side of the 6 pin connector:
With key on the "On" position: pin wires- 3,4,5,6 bright light; pin 2 barely lights, very dim
With key in the "Start" position: pin wire- 3,4,5,6 bright light; pin 2 barely lights

I am not well versed in meter usage, I do have one and will check YouTube on usage this afternoon. I have pulled the rear body/fender/seat off to make sure that the connector to the transaxle correctly seated, with the seat off I have a jumper across the seat safety switch as well with the back unit off. I also checked to make sure that the PTO connector is seated, I did clean with electrical spray cleaner these connectors while rebuilding the tractor.
Mike

MJM48 said:

Hi Will,

No luck. I did notice that the yellow/black wire should be #416 not #415- both 415 and 416 are yellow/black wires. I'll list what I've currently got set-up. I have put the Deere wire in pins that mate with the Kohler 6 pin connector. I have also attached the print out of the ECU pin configuration.
Deere side connector:
Pin #1- empty (empty on the Kohler side)
Pin #2- white wire #940 [According to LX173 Electrical Schematic, pg 5-13 went to "A1 Ignition Module."]
Pin #3- new wire (red small gauge to match Kohler gauge) to MIL on dash- I have checked to make sure on correct polarity of Malfunction Lamp.
Pin #4- yellow/black wire #416 [on the Deere schematic went to "Y1 Fuel Shutoff Solenoid"]
Pin #5- tan wire # 620 [on the Deere schematic went to "B1 Engine Oil Pressure Switch/light"]
pin #6- purple/white #721 [on the Deere schematic went to "M1 Starting Motor"]

Kohler Engine side 6 pin connector:
Pin #1- empty
Pin #2- white wire [goes to grey connector on the ECU which is called, "Safety Switch Ground"]
Pin #3- black MIL [goes to MIL]
Pin #4- red/white [goes to black connector on the ECU called, "Ignition Switch (Switched +12V)]
Pin #5- green [goes to "Oil Pressure Switch"- no pressure switch on engine. I have the old one and when I change the break in oil at 25 hours may try to install in provided port.]
Pin #6- dark blue [goes to "Starter Motor"]

I have run the following test lamp check this was performed on the back of Kohler side of the 6 pin connector:
With key on the "On" position: pin wires- 3,4,5,6 bright light; pin 2 barely lights, very dim
With key in the "Start" position: pin wire- 3,4,5,6 bright light; pin 2 barely lights

I am not well versed in meter usage, I do have one and will check YouTube on usage this afternoon. I have pulled the rear body/fender/seat off to make sure that the connector to the transaxle correctly seated, with the seat off I have a jumper across the seat safety switch as well with the back unit off. I also checked to make sure that the PTO connector is seated, I did clean with electrical spray cleaner these connectors while rebuilding the tractor.
Mike

Click to expand...

Will,
Additional information: I have checked all fuses on the Deere and the Kohler to make sure no problem there, also this is a brand new battery. In rebuilding I pulled the key switch module off the dash and blew with low pressure compressored air 23 years of dust off and reinstalled.

MJM48 said:

Will,
Additional information: I have checked all fuses on the Deere and the Kohler to make sure no problem there, also this is a brand new battery. In rebuilding I pulled the key switch module off the dash and blew with low pressure compressored air 23 years of dust off and reinstalled.

Click to expand...

The first thing that stands out to me is that the #721 purple wire should not have power unless the keyswitch is in the start position. This wire activates the starter solenoid. I'm assuming your new engine has a solenoid shift starter (solenoid piggy-backed onto starter). If the solenoid is not on the starter, then we will have to wire it up differently. If the purple wire has power with the keyswitch in the run position, then there is a problem on the tractor side that needs to be corrected first.

Pin #2 is a ground and shouldn't light at all. Let's disconnect that for now.

Will1988 said:

The first thing that stands out to me is that the #721 purple wire should not have power unless the keyswitch is in the start position. This wire activates the starter solenoid. I'm assuming your new engine has a solenoid shift starter (solenoid piggy-backed onto starter). If the solenoid is not on the starter, then we will have to wire it up differently. If the purple wire has power with the keyswitch in the run position, then there is a problem on the tractor side that needs to be corrected first.

Pin #2 is a ground and shouldn't light at all. Let's disconnect that for now.

Click to expand...

Will,
Had partial success late yesterday afternoon. In rechecking all connection I found I had a poor gound connection, fixed that, after pulling the white wire got spark/turned over engine- didn't run though. Just as I got the spark/turn over we had a ranch emergency arise and I didn't get back to the Deere Saturday. Such is ranch life. Off to church today, will try and get Deere started tomorrow. Will post results as to what happens.

MJM48 said:

Will,
Had partial success late yesterday afternoon. In rechecking all connection I found I had a poor gound connection, fixed that, after pulling the white wire got spark/turned over engine- didn't run though. Just as I got the spark/turn over we had a ranch emergency arise and I didn't get back to the Deere Saturday. Such is ranch life. Off to church today, will try and get Deere started tomorrow. Will post results as to what happens.

Click to expand...

Will-

Sucess, the tractor is running. I wanted to give information for anyone who might want to do an engine swap on their LX series particularly regarding the wiring. The Kohler EZT 740 engine will fit the LX chassis, with some modifications. The biggest issue is fitting the muffler. That requires the engine to be moved forward an inch or so for the muffler to mount to the engine and clear the front of the chassis. That requires drilling new holes in the chassis deck to mount the engine. It also requires adjusting the pulley idlers to allow the stock drive belt to fit with the engine further forward. Making the hood fit required a fair amount of modification- lots of cutting to clear the wider, taller engine.

Regarding the wiring. The initial problem was a grounding issue. I installed in addition to the engine grounding wire as second grounding wire directly to the chassis. I purchased a Molex 6 pin connector from Amazon along with the pin remover tool, total cost $15.00. The following is the list of which Deere wires went in which numbered connector slots to mate with the 6 pin Molex connector on the new Kohler engine.

Pin #1- empty (empty on the Kohler connector.)
Pin #2- Deere white wire #940
Pin #3- New wire to the new installed dash Malfunction Indicator Lamp (MIL)
Pin #4- Deere yellow/black wire #416
Pin #5- Deere tan wire #620, oil sensor wire
Pin #6- Deere purple/white wire #721 this connects to the starter assembly

The Deere red wire #205 was not used, I capped it and then wrapped the wiring assembly. With just the yellow/black wire, the MIL wire, and starter wire, the engine would crank but not start. It was necessary to have the Deere white wire in the #2 pin to start the engine. I've attached a couple of pictures showing the completed project. The clear boxes on the sides of the hood are a Rubbermaid 9" x 12" clear polycarbonate type dishs modified to cover the sides of the engine that was too wide for the original hood requiring the hood sides to be cut. Covering the side probably not necessary for most, but we mow down tall weeds with this tractor on the ranch. I wanted to protect what would have been open engine sides from brush.

I hope this might help anyone who is thinking of doing an engine swap on an LX series tractor. I want to thank you, Will, for your time and advice in walking me through this project. It is alway good to have sucess.
Mike