# Kohler Diesel Genset Issues - cannot start



## Jass (Dec 7, 2020)

Recently purchased a Kohler Diesel Genset where it had been set up with a remote programming/monitor setup, but that remote setup is no longer in place and there are likely some lingering setups and wire connections that could be causing issues for the Genset. For example, I see on the rear circuit card of the controller on the right side on the TB3 terminal block set of terminals, that the 1A wire has been re-routed to go to the exterior of the controller likely over to the remote monitor area that had been in place before I purchased the Genset, and that a wire runs back into the controller and to terminal 1A on TB3. Additionally, there are wires routed from outside the controller to terminal block TB2 terminals BCF and LF – no idea if this is an issue relative to faults being observed and getting the GenSet started???. Genset details follow:

Kohler Diesel Fast Response Generator Model# 20ROZJ,
Serial # 600858
Decision-maker 340 Controller Assembly
Set up for single phase and 24V with approx. 238 hours per controller menu’s.










Recently purchased where it had been set up with a remote programming/monitor setup, but that remote setup is no longer in place and there are likely some lingering setups and wire connections that could be causing issues for the Genset. For example, I see on the rear circuit card of the controller on the right side on the TB3 terminal block set of terminals, that the 1A wire has been re-routed to go to the exterior of the controller likely over to the remote monitor area that had been in place before I purchased the Genset, and that a wire runs back into the controller and to terminal 1A on TB3. Additionally, there are wires routed from outside the controller to terminal block TB2 terminals BCF and LF – no idea if this is an issue relative to faults being observed and getting the GenSet started???.
I am trying to get the engine to turn over so I can get it started.

When I connect two 12V batteries to create the required 24volts, the Controller displays has the System Warning and the System Shutdown lamps illuminated and when the Master Switch is rotated to Run in attempt to start the generator nothing happens, not even a click from the solenoid on the starter.
Using the controller to try to see why the System Warning and the System Shutdown lamps are illuminated, I press the “Reset Menu” button and then use the down arrow button to scroll thru the faults and the “Emergency Stop” and the “Low Coolant Temp” errors/faults are displayed.
When I press the “Reset Menu” button again and then select “7” for “Engine Status” and then select the down arrow to scroll through the status, is shows Battery VDS at 25.6V, Oil Pressure at zero, Coolant Temp at 80 degrees F, Engine Start at No, and the countdown at 00.
I have the Kohler Operation Manual TP-5829 for 20-2000kW models and the Decision-Maker 340 Controller, but I am not finding anywhere that says how I can reset the faults. I have rotated and pulled out the Emergency Stop Switch, but that does not seem to change the System Shutdown lamp illumination nor the status message on the main display.

Might anyone have any experience with these generators/controllers that could tell me how I get these faults reset and the Genset to turn over? Any/all help appreciated


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## ToolLover (Jan 13, 2020)

Post a picture of the schematic.
This is all I can find...


http://www.kohlerpower.sg/onlinecatalog/pdf/tp6140.pdf


Once you find where each of the blue wires that are coiled on top of the controller go, you can then go the the schematic and get an idea of the start sequence.
On page 25 go to the start sequence board.
I feel for you as the guy that pulled this out had no concern about getting it running again.
You are going to have to reconnect the "Decision Maker box" to those blue wires.
Go to page 25:
As for the low coolant LCT Terminal strip TB4 on the interconnect board pin 3 wire 35 A
The the emergency stop ESS is just above the LCT on TB1 pins 1 & 1A.
The battery problems could be from the Interconnect board also and then there are those five fuses that feed the DC voltage.


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## ToolLover (Jan 13, 2020)

You might want to connect to the Ziller.com forum.
There are some Generac guru's over there.


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## Jass (Dec 7, 2020)

Thanks for all the replies. 
I looked at the document referenced but that one is for the Decision-Maker 550 controller whereas I have the Decision-maker 340 controller, and they appear to be quite different. I have document tp-5829 which I got from Kohler support, so I need to study that better, but I am not a circuit expert, and the document is not the most intuitive. 
As for the wires coming in from what was the external remote control center, as stated above there are just four wires, wire 1A on TB3 was disconnected from the terminal block and is routed out of the controller and a new 1A enters the controller and is connected to the 1A terminal, plus there are TB2 terminals BCF and LF that have wires connected to the to them and routed out of the controller.
Anyway, based on the above, maybe that will trigger some other advice?
Thanks,
Jeff


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## Jass (Dec 7, 2020)

So I removed all the wires that had routed to the remote control center and re-connected the 1A terminal and that cleared up the errors and now the GenSet turns over. However, fuel is not getting to the injectors. Fuel gets to the Stanadyne DB2435-5000 injection pump input, but there is no fuel pumping out to the individual injectors. This Genset had sat for maybe two years. Does anyone know if there is something I can do to get the fuel flowing through this injector pump?


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## iowagold (Jan 22, 2020)

there should be a fuel shut down solenoid on the injection pump.
they need voltage to let the valve pass fuel out of the injection pump to the engine injectors.

most of the time a med hi pressure electric diesel fuel pump at 60 psi works to help bleed out air on a pump for a temp injection pump prime. 
that is one of my favorite tricks to save starters on diesel first run ups.

there should be several places in a diesel fuel system to bleed air.
and the last is the individual injector lines at each injector.


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## Jass (Dec 7, 2020)

Thanks. I did verify that there is voltage getting to the terminals on the top of the injection pump for the referenced solenoid. The gauge on the fuel filter console registers at it's max pressure (7 PSI). I also bled the fuel lines at the fuel filter, at the inlet line to the injection pump, at an injector (no fuel being expelled), and at the bypass line out of the injection pump. Fuel is being pumped out of the bypass line by the injection pump, but it is a very small amount.
I am wondering if maybe that solenoid inside the injector pump as stuck on closed from getting gummed up, maybe due to fuel having sat in there and dried up over the two or so years the Genset sat?

If I were to get the 60 psi med hi pressure electric diesel fuel pump, where in the fuel flow would I insert that? The fuel lines run to the mechanical fuel pump driven by the engine to the fuel filter console, then to the injection pump. All of the fuel lines from the mechanical fuel pump over to the injection pump are all rigid steel fuel lines.
Is the objective of using the 60 psi fuel pump to force fuel past the various ports and passages within the injector pump and up to the injectors? If so, maybe I could put a temporary flexible fuel line on the injector pump inlet, fill that flexible fuel line with diesel fuel, and then use my compressor set at 60 psi to pressurize the temp fuel line to accomplish the objective to push fuel in through the injector pump. Thoughts on that anyone?


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## ToolLover (Jan 13, 2020)

I think you need a diesel injection mechanic to answer your questions.


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## iowagold (Jan 22, 2020)

Jass said:


> Thanks. I did verify that there is voltage getting to the terminals on the top of the injection pump for the referenced solenoid.
> Fuel is being pumped out of the bypass line by the injection pump, but it is a very small amount.
> I am wondering if maybe that solenoid inside the injector pump as stuck on closed from getting gummed up, maybe due to fuel having sat in there and dried up over the two or so years the Genset sat?
> 
> ...


send over the exact engine numbers for me.
i can pull up prints here on it.
yea sounds like it is sticking closed on the shut down fuel valve.
did you replace the fuel filters and clean the water separator?

i place the high pressure pump after the lift pump in an area that has "HARD LINES"
and yes it is to free flow fuel through the injection pump.

be care full on the output injection side of the pump as there is 10k to 30k psi pressure as an injection hazard.
on injection lines make sure both ends are not tight for test remove one nut only at the end at the injector and leave
it loose during crank to see if there is air in the system or trash.

oh yea was there black trash or slime in the water separator?
or any rust chips?


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## Jass (Dec 7, 2020)

Paul,
Thanks for your inputs. I did drain the water valve at the bottom of the fuel filter and it looked clean.
The engine is a John Deere engine ser # CD4039D369909; that also has the following numbers on the ID tag: DD15454; FG17527; 24V-SAE4 and was made in France.
The Fuel injection pump is a Stanadyne injection pump model # DB2435-5000, Ser # 8890192, Mfg # RE-47176
Today I put some diesel injector system cleaner in the lines and injector pump to let that sit there for a bit to maybe soften any varnish that built up from dried fuel during the time it sat, and if by chance the solenoid is stuck closed maybe it will free it up?? . I used a little compressor air to push that cleaner into the injection pump from both the inlet as well as the overflow outlet. I then cranked over the engine for a bit to enable the cleaner to hopefully get throughout the injector pump. I will flush that out before I resume trying to start it.


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## iowagold (Jan 22, 2020)

good engine!
they are a real work horse!
new injection pumps are $1600.00
so it is worth the time to go through it!

is this your pump?
click here for the jd pump









snap a pix of the pump you have when you get a chance


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## iowagold (Jan 22, 2020)

hummm
i had a jd a while back that the lift pump was week.
they have a habit to eat the oem mechanical lift pumps.
I replaced it with an electric pump.
still working after 10 years..
it is on a gehl telehandler.

yea check the shut down sol. 
remove it carefully, and see if fuel is free flowing to that point.
and while it is off the engine check the sol for action when energized.
no power is fuel off on these shut down valves.

some of the other brands of diesel engines injection pumps have a lever that the shut down sol hits when it is not powered.
on those you can start the engine and with that valve removed you can finger shut down the engine.
I have for a couple of setups like that a custom machined welded up washer that will bolt up
to the pump for rescue to get it loaded on a trailer to get it back to the repair shop.


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## Jass (Dec 7, 2020)

here is a picture of the fuel injection pump.
I had removed the side inspection port and everything looked clean inside, no rust or anything, just clean diesel fuel that spilled out. Otherwise, the unit is unmolested and basically new with just 238 hours on the genset.


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## iowagold (Jan 22, 2020)

take a look at this check sheet
*click here for the pump help sheet*


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## iowagold (Jan 22, 2020)

this is for another brand of pump
but the basic testing is the same


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## Jass (Dec 7, 2020)

Looks like I am in the no start, no fuel to injectors problem area. I think I need to check that the solenoid functions correctly. The cover on the pump for where that solenoid is has tamper-proof Torx screws attaching it. I do not have any of the tamper-proof Torx bits so iI have a set of them on order. 
I plan to leave the pump mounted on the and just remove the cover for the solenoid to check it. 
I assume to check that solenoid all I need to do is apply power and the solenoid piston should move in/out. Any tips/tricks I should be aware of for either removing that solenoid cover or for testing the solenoid?
Hopefully that is the issue as that would be a relatively simple fix.


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## Jass (Dec 7, 2020)

thanks for the solenoid test video, that is helpful


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## iowagold (Jan 22, 2020)

check the voltage first
make sure it is a strong 12 volts. at the sol.

if you have help
have some one switch it on and feel the sol for a click.
that would check the electrical part.
then look for a stuck shut down valve


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