Thread: MSX 140 Electrical Fault
06-30-2010, 11:09 AM #1
- Join Date
- Apr 2009
MSX 140 Electrical Fault
We have a major issue with our 2003 MSX 140, half the time it runs fine then all electrical power to spark, fuel, and MFD display is severed. This only happens after turning off the engine and attempting to restart. (After being stranded on the ocean last weekend, I won't ride again until it is fixed) The starter motor turns but no matter how long we hold the start button, nothing happens. (No clicking of fuel pumps or spark visible and display remains off). All fuses are good. We took the ski into the shop and had the EMM diagnosed, it came back fine. We replaced the Crank Position Sensor but still have the same problem. It is very frustrating because when it runs, it runs perfectly, thus, when we have taken it in for service, no trouble codes are being tripped.
If we manually turn on the display by pushing the blue gauge button while holding the start button, the rpms read Zero.
We are having a very hard time figuring out where to look for the problem. Has anyone heard of this happening or have any idea what the issue could be? Thanks
06-30-2010, 11:25 AM #2
- Join Date
- Jul 2007
- near Toronto, Canada
The MSX 140 starter motor is directly controlled by the Start button. The Start button only affects the starter motor.
The EMM and the rest of the system (including the NGI display) do not get a signal from the Start button.
Instead, the EMM watches for an electrical signal from the stator inside the flywheel. When the EMM senses the engine rotating (cranking), it then 'wakes up' the EMM. The EMM then sends an RPM signal to the display, which in turn also wakes up.
Since your display remains asleep, that means the EMM is also not seeing the engine turning, or the EMM thinks the lanyard is not in position. Ohm check the lanyard switch.
The problem could be in the EMM, or the stator, or CPS (Crank Position Sensor).
When the shop checked the EMM, did they find any stored codes?
Has it failed again since the shop had it?
If necessary, you can water test it on the trailer. Strap it down front and rear, and back down the launch ramp until the jet pump intake is submerged. Now you can run it as long as necessary to trigger the problem, and do some diagnostics.
When it fails, what does it take to get it going again?
Remove the CPS from the top of the flywheel housing. Look for any signs of damage or metal debris on the sensor bottom. Measure the CPS ohms - should be under 200, typically around 140 ohms.
Remove the 12 and 8pin connectors from the EMM, and look for signs of water or corrosion. Do the same with the large 40-pin connector, which is held in place with a hex bolt.
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