Question on Mahindra Emax25 fuel shutoff solenoid

[Catsailr]

I have a 2014 Emax 25 that got water contamination and had to drain fuel,replace filter and bleed and all was fine a couple of weeks ago went to use again and more water contamination so this time I dried out tank and replaced with fresh fuel, cleaned filter and dried as it was brand new and even though in contact with some water it looks fine. Re bled everything but not getting fuel at the injectors so I suspect fuel cutoff solenoid. It retracts when starting but stays out when in run position. I tried checking voltages at the connector and am only getting 5.4V in the run position on the red/wh. My question is there are two sets of wires running to that solenoid white and black on one connector and black, red/wh, pink/wh and black on the other. I have parts and service manual on order with Bill's tractor and am in need of schematic or knowledge of the wires going to the solenoid and what voltages to expect. I suspect the solenoid is bad but don't want to spend $200 if I don't need it. Thanks, Richard

 

[Dave M7040]

This is just a quick response hoping it will be of some help to you.

Typically these solenoids have two sets of electrical windings inside much like starter solenoids do.

A high current thus strong winding to move the solenoid and then a second winding to hold the solenoid in position. The two winding work together at first and then the high power winding drops out of the circuit as internal electrical contacts are opened by the solenoid plunger's movement.

This image is of the internals of a Kubota engine stop solenoid but most are similar.

Item 18 is the relay which powers the solenoid item 19.

Item 19 has an internal set of contacts which open when the solenoid plunger has moved and then only the hold winding remains powered.

Your voltage measurements are of little help to me not knowing where the voltage was measured and to what ground or reference.

In the Kubota image, relay 18 sends 12 volt power to both solenoid windings immediately. Then, once the plunger has moved, the internal contacts open and the pull coil is de-energized.

What might help me is for you to unplug the connector and while the key is activating the relay, check both colored wires for 12 volts to ground such as the starter bolts or battery terminal.

Then I suggest you measure the voltage between either of the colored wires and the black wire in the connector as this would establish that the wiring is grounded as it should be.

Lastly, measure the ohms or resistance of either colored wire to the black wire.

Dave M7040

 

[Catsailr]

This is just a quick response hoping it will be of some help to you.

Typically these solenoids have two sets of electrical windings inside much like starter solenoids do.

A high current thus strong winding to move the solenoid and then a second winding to hold the solenoid in position. The two winding work together at first and then the high power winding drops out of the circuit as internal electrical contacts are opened by the solenoid plunger's movement.

This image is of the internals of a Kubota engine stop solenoid but most are similar.

Item 18 is the relay which powers the solenoid item 19.

Item 19 has an internal set of contacts which open when the solenoid plunger has moved and then only the hold winding remains powered.

Your voltage measurements are of little help to me not knowing where the voltage was measured and to what ground or reference.

In the Kubota image, relay 18 sends 12 volt power to both solenoid windings immediately. Then, once the plunger has moved, the internal contacts open and the pull coil is de-energized.

What might help me is for you to unplug the connector and while the key is activating the relay, check both colored wires for 12 volts to ground such as the starter bolts or battery terminal.

Then I suggest you measure the voltage between either of the colored wires and the black wire in the connector as this would establish that the wiring is grounded as it should be.

Lastly, measure the ohms or resistance of either colored wire to the black wire.

Dave M7040

Thanks Dave! I do have two connectors and one set does get 12v the other only has 5.4 so I'm waiting on service and parts manuals due here Friday to further troubleshoot. I will try your suggestion of unpluging the connection that I do get a 12v reading on and see if the other changes in run and start positions from the 5.4 it has in run mode. I always use battery ground as my neg side of my meter. Very small gauge wires, three on one connector and two on the other. I double checked frame to battery ground and it's a good connection. I'm hoping my dealer will take some readings for me as well on a working machine. I just found out a new solenoid is $1100 not 200 so I'm want to be **** sure it's bad and no way to work around it before I order. Thanks, Richard

 

[Dave M7040]

Richard

I think your problem may be that the device in your photos is not the engine stop solenoid but a sophisticated engine speed governor.

The word "proportional," on the device is the big clue. My reading on the product brought me to this link which I have now studied. The documents title says a lot.

http://www.traycana.com/catalogues/apecs/APECS3000.pdf

The passage below is taken from the manual in the link above. I would never have imagined a Mahindra (no offense to Mahindra owners intended) would have this level of technology in a farm tractor.

APECS 3000
®
Electronic Engine Speed Governing System
Manual SE-4049
Woodward

Chapter 1.
Understanding the System
System Basics
APECS is an acronym for Advanced Proportional Engine Control System. It provides a
means of controlling engine speed by adjusting the fuel control lever with an actuator.
The heart of the system is a powerful microprocessor-based controller that processes
the signal received from a speed sensor and compares it to the desired speed setting.
The output of the controller is a pulse-width modulated signal that drives a precision
proportional actuator connected to the engine’s fuel control lever. The actuator converts
the signal to an output shaft position, proportional to the duty cycle of the pulse-width
modulated signal.
The APECS system provides isochronous engine governing (i.e., engine speed is
maintained at the commanded setting, regardless of load) through a wide speed range.
APECS is suitable for use on both compression ignition (diesel) and spark ignition
(gasoline, CNG, LPG) engines.
Woodward developed the APECS system for a variety of on- and off-highway
applications. Typical applications include generator sets, compressors, construction
machinery and farm vehicles.
WARNING

An overspeed shutdown device, independent of the APECS
system, should be provided to prevent loss of engine control that
may cause personal injury or equipment damage

This last paragraph above gives vital info. It clearly states that the engine using a proportional control system must have a way to shut down the engine completely independent of the electronic speed controller.

You do likely have an engine stop device. It could be an engine stop solenoid or a cable you pull but the device you photographed is not it.

Dave m7040

 

[Dave M7040]

Richard

I came across this Mahindra recall notice on their web site in North America which was issued in Nov 2015 so may not apply to your tractor.

Perhaps you have this problem with cracked fuel lines and that is why your tractor is not wanting to start. cracked fuel lines can both leak and allow air into the injection system.

Dave M7040

Dear Mahindra Customer, Mahindra USA is voluntarily conducting a safety recall of certain eMax tractors.

Problem:

One or both of the fuel delivery or the fuel return pipe attached to the diesel fuel tank can
crack at their base causing fuel to leak from the diesel tank, posing a fire hazard

Product:

Mahindra Model eMax Compact Tractors. Tractors are driven by diesel engines and range from 22-25 horsepower.

What to do:

As part of this Mandatory Safety Campaign affected customers should contact their authorized Mahindra dealer as soon as possible for an appointment to schedule the free
repair.
The repair will consist of a reinforcement with epoxy of the base of the fuel delivery and the fuel return pipes.
Affected customers have been sent a direct mail notification in November 2015.
We sincerely apologize for your inconvenience caused by this Safety Recall Notice.
You may contact us at (866)856-8099 in case of any questions.

 

[Catsailr]

Hi Dave,

Thanks for all of your earlier input. I just got the tractor back $2100 later and it turned out to be the injector pump that was $1600. I'm going to punch thru the catch tray and glue in a drain line so water can't pool. Also having a line of 40" trees taken down next week so I can have a proper pole barn instead of tarps. Richard

 

[Dave M7040]

Glad your Mahindra is running again.
$1,600 is a lot of money

Dave M7040