MoTeC Global Forum

Hi Guys,

Could use your help on this one.

I have an M400 used in a drag race application on a Suzuki Hayabusa engine with a slider clutch (no clutch lever/pedal). It has a 6 speed trans (1-3 auto) and I'm using a button on the handle bars wired to Dig_In_1 to activate the Gear Change Ignition Cut. The gearbox has a voltage potentiometer and the m400 gear detection has been configured for gears 1-6. I'm also using a pneumatic ram to complete the physical gearbox shift.

Trouble is - the Ignition cut is not functioning.

I'm testing this in the shop at low RPM and I am getting a positive the Gear Change Cut Request to the ECU when pressing the Dig1 button, but the Gear Change Cut is not Activating. My air ram functions because the solenoid is wired to the same button. I alos see a tming retard on my data logs when the shift happens, but no ign cut?

Cut Mode = 2
Cut Source = 1
Cut Level = 100
Retard (Trim) = 45

Thanks,
Mike -

minimum TPS or RPM values you're exceeding to activate the GCIC?
if you can post your map file I can have a look for you.

What is the value of Gear Change Delay for the current gear? That determines the maximum time of the cut. If you have Next Gear Terminate set to 1, then the cut can end early when the next gear is detected.

Are you sure your Hayabusa has a gear potentiometer, and not just the factory gear switch?

Min RPM = 1500
Min Throttle Pos = 0

I am using an aftermarket potentiometer from Motec/MillSpec, not the OEM.
Delay settings are.
1st Gear = 0.080
2nd - 6th = 0.045

Need to pull the file and will post it here. Thanks

Attached is a recent log. Some settings changed from earlier post as trying various things to get the ign cut to work.

Your log shows your gear detection always thinks you are in 1st gear. Does your gear detection work? Can you manually change the gears to make sure that all gears are detected?

Please Log Gear Sensor Voltage (found in Data Logging Setup -> Other Sensors).

Also, I notice that the Brake Status is true. Any chance this prevents the Gear Change Ignition Cut from activating? Can you disable this function to test (or disconnect the brake switch?).

Thanks David,

Gear detection works, I've tested the various positions of the gearbox and I see the expected voltages and gear numbers displayed in the ECU. Since we are running a 1-3 auto in a drag race application, we cannot shift that in the shop, it needs to be under load on the track. I've manually put it in 1st to test the ign cut and have removed the air line to the ram preventing the physical shift to keep the trans safe. I have delay values configures, so I expect to see the ign cut when the button is activated even if the GPS does not move to 2nd, 3rd, etc.

I will double check the break status config. I suppose that could be interfering but nothing was set to specifically disable GCIC based on brake status. Will have a look - thanks.

David - thank you for the tip.

The brake signal was the cause. We've turned it off and the cut is now as expected.

Very much Appreciated!
Mike -

Thanks for letting us know the resolution.

We all learned something new!