MoTeC Global Forum

Hi all,

I am trying to set up paddle shifters with a electric solenoid actuator with an M150 on a Formula SAE car (sequential gear box). I've read through the docs and watched videos (HP Academy) on setting this up.

As far as the hardware configuration goes:

+ Paddles going to universal digital inputs
+ Solenoid actuated by two separate relays that are controlled by Low side ignition outputs
+ Gear position sensor
+ No clutch sensor of any kind - Disabled
+ No Gear shift mode switch - Set to Manual

Here is the current behavior:

+ Shift requests, gear position, and solenoid actuation all work as expected.
+ If I up-shift with the engine off -> Shift with Ignition/Fuel Cut is requested
+ If I up-shift with engine running and in 1st gear but with clutch in (throttle or no throttle/wheels not spinning) -> Shift with Ignition/Fuel Cut is requested
+ If I up-shift with engine running and in 1st gear (throttle or no throttle/car moving) -> Shift is requested but No Ignition/Fuel is requested.
+ Gear shift diagnostic reports "OK" the entire time except when it detect the shift failed.

Any suggestions are much appreciated!

Make sure your gear ratios are correct (including final drive). The ignition cut is normally caused by the Gear Shift Engine Speed Limit (you do have Gear Shift Engine Speed Limit mode enabled don't you?) attempting to slow the engine to the required speed for the next gear ratio.

I've verified gear ratios.
So you're saying ignition cut should not happen at all if Gear Shift Engine Speed Limit mode is disabled? because it was disabled during all of my tests and ignition cuts did happen under the specific circumstances I previously described.

Upload an archive of your config and we can take a look. Guessing always seems to take much longer.

Also helpful would be a log of shifts with and without ignition cuts.

Attached is the archive and a log containing the tests I described before. The shifts that do have the ignition cut and fuel cut are with the car not moving, the ones without the cuts are with the car moving.

Attachments: ...

Looks like the file attachment didn't work? Anyway the channels to look at which should point you in the right direction are:
Gear Shift Type: make sure the type looks right - e.g. shows Up Shift Power On when you are accelerating, if not check setting for Gear Shift Power On Throttle Position
Gear Shift Engine Speed Mode: you may find that with the vehicle not moving it is in the Speed Matching Disabled mode and is using the Gear Shift Ignition Cut Main setting, but when the vehicle is moving then Speed Matching is Enabled, but calculating wrong so it doesn't need an ignition cut. If that's the case you need to verify all your settings around that are correct (and there are a lot! Wheel circumferences, Gear Ratios, Input/Output Ratios, Final Drive Ratio, Gear Shift Engine Speed Match %, probably some more). You can quickly determine whether the ratio calculations are correct if you look at the Gear Estimate Ratio vs the value reported by Gear Ratio.
Engine Speed Limit: When the Gear Shift Engine Speed Mode is Upshift Speed Matching Enabled you should see the engine speed limit drop down to a value very close to the actual speed limit. If you ratios have all checked out correctly and the engine speed limit isn't coming down low enough, your settings for Gear Shift Engine Speed Match % may be wrong

Got it working by disabling the Engine Overrun feature. Don't know why that was causing it because it was not even active in the instances where the ignition/fuel cut would fail, but it works with it disabled completely.