MoTeC Global Forum

Hello, I am with a formula SAE team and we are having an issue where the timing is advancing with rpm.


The engine will start and run and reaches cycle lock. However, When I have the ecu in "timing mode" set at 0 degrees the timing will change drastically (30+ degrees) with rpm using a timing light.

I believe it is an issue with the magnetic sync sensor on the cam. But I can not figure out how to do any sort of ref sync capture using m1 tune.

Any suggestions or Ideas would be helpful.

Which package and version are you using.

The later system 1.4 GPA and GPR have ref/sync capture function. ( unsure about other system1.4 packages)

System 1.3 packages do not have ref/sync capture function.

However the sync sensor on its own should not cause the timing to drift.

But It could cause the timing to jump suddenly.

Are you using a 12 tooth trigger wheel (no missing teeth?)

And is the timing drifting gradually with rpm or jumping 30 degrees suddenly?

baselkwt wrote:Which package and version are you using.

The later system 1.4 GPA and GPR have ref/sync capture function. ( unsure about other system1.4 packages)

System 1.3 packages do not have ref/sync capture function.

However the sync sensor on its own should not cause the timing to drift.

But It could cause the timing to jump suddenly.

Are you using a 12 tooth trigger wheel (no missing teeth?)

And is the timing drifting gradually with rpm or jumping 30 degrees suddenly?

we are using a 1.3 package.

12 tooth no missing teeth crank

3 tooth cam sensor

Using Honda bike sync.

the timing appears to linearly increase with rpm.

If the timing is changing by one tooth (30 degrees), then it's likely you are missing the teeth. Have you tried using an oscilloscope on your speed reference (crank) or syncronisation (cam) signals?

Note what the peak-to-peak voltage is at various RPMs. Compare this to the Speed Pin Hysteresis and Syncronisation Pin Hysteresis. You might also need to play with the Blank Ratio, Narrow Pitch Threshold and Wide Pitch Threshold as this will allow or filter out mis-identified teeth detected.

Use the Ref/Sync tab in the Initial Setup and make sure the Time Graph has signals like Engine Speed and engine Synchronisation Pin Diagnostic.

Look at the Engine Speed / Synchronisation Voltage Miniums and Maximums, too.

The clues should be found in there.

If the ecu was skipping a tooth the cycle lock status should change. And even if it didnt the effect would be the ignition advance suddenly decreasing by 30 degrees.

A linear increase in timing by 30 degrees is very strange.

Crank trigger sensor delay would have the effect of reducing the ignition advance as well so thats probably not it either.

It could either be a large (impossible) amount of crankshaft twist between the trigger wheel and where you are checking your timing mark. Or there could be some loose parts causing it.


Or it could be that the ignition>driver> delay is set much higher than required in M1 tune (but that would also have to be an impossibly high number. E.g. no less than 830 microseconds for 30 degree drift at 6000 rpm )

Make sure the ignition>driver>firing edge is also set correctly (falling/rising)


Make sure the settings are correct and that the trigger and what you are using to check the timing mark are fastened correctly.

Depending on the package that you are using there may be a trim table that is causing this.


If you are using GPA/GPR see of you could switch to the latest version, a ref/sync capture may still help diagnose the problem.

Thank you for the response.

I am stumped as well. Our other engine on the dyno ran with out any issues.

The only thing that has changed in the car is the wiring diagram and a 2011 600rr compared to the dyno having a 2009 600rr

The ignition driver is set to falling edge, which I believe to be correct

Ignition driver delay is set at 40 mirro seconds which seem normal

We have an M1 build license using a modified gpr 1.3 package Im not sure we have paid for the updated 1.4

Hi,

If you email support @ motec.com.au with the serial number of your M1, I can let you know if you have an updated build license.

What other changes have been made between the 2009 and 2011 engines and looms? there might be a small change such as the polarity being swapped on the Sync Mag sensor pins, that swaps the signal from falling to rising, or vice versa, between the models.

Im going to hook the magnetic sensors up to an oscilloscope and hopefully get a better idea of whats going on.

So the issue is resolved!

After hooking up an oscilloscope I found the cam sync sensor was on rising edge instead of falling edge.

Thanks for y'all help