MoTeC Global Forum

During dyno testing this past week, the engine would cut out at around 9600 rpm, without any apparent reason. I've reviewed the logs carefully, and there's no fuel or ignition cut and the engine speed limit is 10000 rpm at the time of the cut-out/stumble.

The car/engine is a Radical SR8, and the redline should be fine to 10500. I'm using custom GPR-based firmware, with dual DBW throttle servos.

The only thing I can see is a throttle pedal diagnostic of Open Warning, caused by a main and tracking reading of 103.1%. This was in place for about 4 seconds before the drop in rpm. Can an Open Warning cause this?

If not, what else might it be? I'm happy to provide the log if anybody wants to take a look. I'm back to the dyno early next week so any additional logging is possible as well.

Thanks!

Hi,

This can cause the M1 to shutdown the throttle servo as it is exceeding the safety conditions for the DBW, I would recalibrate the Throttle Pedal to ensure that the pedal cannot exceed 100% in all operating conditions. To calibrate pedals like this, I will have as much pressure that is possible on the pedal to get the highest reading (some OEM pedals also have lateral movement that will also change the signal) and then pause the time graphs and move the cursor back to this point and Q the Scale for the pedal at this point.

This will usually result in a normal opening position around 95%, I then change the Throttle Pedal Translation to give me a 100% request at that position so you still get a fully open throttle servo.

Hi Stephen,

Understood. I've implemented this change and it's back to the dyno tomorrow AM.

Many thanks!

Hi,

The throttle errors are fixed. Many thanks for the guidance on that.

However, the engine is still cutting out about 9200 rpm for no apparent reason. You can see it in the screen snip below. Closer examination seems to be more like a ref/sync problem. Any guidance for how to narrow that down? Log/package can be provided if someone wants to look.

Hi John,

What is the Engine Load Average Engine Speed Limit set to?

Hi Stephen,

It's set to 10000 rpm across all cells:

Hi John,

Can you send the logging through thanks.

Hi Stephen,

Sent via dropbox link.

Post the calibration so we can help you. Shouldn't be hard to find.

Thanks, posting calibration: