MoTeC Global Forum

Hello,
I keep getting the "Error Ref Runt". I'm using a 60-2 wheel at the crank with a hall sensor. What normally caused the Ref Runt error?

I went through the Webinar regarding ref/sync error but couldn't understand what ref runt means.

Please help..

Cheers
Andy

The Runt means that there is a noise pulse that is present but is lower than the amplitude filter (Mag Sensor Level table). The mag sensor level table tells the ECU to ignore any signal with lower voltage than the table.

For example, if the signal is 3v positive you would set the Mag Sensor Level table to about 0.7-1.0v. A noise signal of 0.6v would probably cause a Runt warning but seeing as how it was below the Mag Sensor Level it does not cause a problem.

The Runt is a warning telling you the ECU can see something but it is not causeing any problems, just something to be aware of. This is covered in the Ref Sync Trouble Shooting webinar.

Hey Mark,
The hall sensor I'm using is a Cherry Hall sensor GS100502, I installed a pull-up resistor between the vcc and the input signal. Is the pull-up resistor necessary? Does the M400 ref input already have a pull up resistor internally when configured for hall sensor?

Cheers
Andy

There is no need for any external pull up with any MoTeC ECU, this is why there is a Hall option in the set up.

I would be very suprised if the sensor will work with 60-2, the tooth frequency will be very high and I doubt that sensor will cope.

Like I said the Runt is only a warning and will not cause any engine running problems.

Hey Mark,
Thanks for the input, I really need to sort this out before getting the car fully tuned. I get the to fire up with the current setup which is 60-2 wheel with the Cherry hall sensor. here is the ref/sync capture.



Once the car is up.. I tried to log the ref/sync voltage through logging and this is what I got at around 620 rpm(idling). The resolution of the crank signal looks like below. Why does it work during the ref/sync capture without the car running but when the car is running.. the logging ref/sync look pretty bad?



By the way, do you know any hall sensor which will work with a 60-2 wheel?

Thanks for all your help.

Cheers
Andy

The logging of the ref/sync voltage channels is a max of 200Hz which is no where near enough, the ref/sync capture does it much, much faster. You should never try to log the ref/sync voltage as a way of looking at the exact pattern, it will not work for this.

The current Gen 4 chev V8s have a Hall sensor that would work on a 60-2 (what they have standard) and will also handle plenty of temperature.

Can I do ref/sync capture while the engine is running?

Also.. since I already have the resistor installed externally, can I switch the ref sensor setting from Hall to Magnetic and set the trigger voltage setting to 3.x volts(what's the exact voltage setting in M400 when sensor type is Hall?)

Thanks
Andy

You can do a ref/sync capture at any rpm.

ive done it at 6000rpm before.

Crank mag trigger looked fine ( off the scale with voltage ) and cam trigger quite distinct, although the "noise" around the 0v line was quite apparent although below filter levels.

Yup,
Did a 3000+ rpm ref/sync capture as well as 4000+k ref/sync capture and the graph looks good. Thanks everyone for your input!