MoTeC Global Forum

I have my motec m400 on my v-twin 800 can-am. It syncs up nice while turning over on the bench but about 5-8 seconds of cranking it sets the code error ref noise tr. I have maxed out the noise filter and it seemed to help a bit. Is this anything to worry about? I have to finish the wiring up to start it. I tried to attach my ref capure but it wont allow rsc2 to attach...

Your crank sensor's wiring is reversed.

Fix that and then try

Thanks! I will do...

stevieturbo wrote:Your crank sensor's wiring is reversed.

Fix that and then try

Thanks! hat did the trick-everything is good. Ready to do initial fire up soon..

another question- I have a device that requires a distributorless tach driver to get its signal for rpm display. I have used a msd 8913 tach driver previously to run it. I am wondering can i use a aux out set as Tacho to drive this device? I am testing it on the bench with that aux set to tacho and I have ref and sync from motor hooked up for the motec to get is syncd signal ok but my device will not display any rpm when I crank it. I have 260 rpm displayed on the motec screen.

Does it need to be actually running to send a signal out for tacho?

thx

The ECU doesn't care which way around the sensor is you just have to tell it whether the signal is rising or falling in the software. So if you have reversed the wiring, the signal will now be falling. Make sure the Ref sensor edge polarity is set to falling.

The output will work if the ECU is getting a readable ref signal, which if it is syncing up and the dash is reading an RPM value then it will be fine. The output from the ECU is a switch to ground so the tacho will need to pull the voltage up. You would have to check the documentation for the tacho but most likely it will require a pull up resistor to 12V. A value like 1k is probably about right.

adrian wrote:The ECU doesn't care which way around the sensor is you just have to tell it whether the signal is rising or falling in the software. So if you have reversed the wiring, the signal will now be falling. Make sure the Ref sensor edge polarity is set to falling.

The output will work if the ECU is getting a readable ref signal, which if it is syncing up and the dash is reading an RPM value then it will be fine. The output from the ECU is a switch to ground so the tacho will need to pull the voltage up. You would have to check the documentation for the tacho but most likely it will require a pull up resistor to 12V. A value like 1k is probably about right.

So I didnt have to change the polarity around??? just the rising or falling edge setting? So that being said, I did change it and it is opposite to what I have posted above, so what should I have it set to now? Rising now since it was falling originally as I had posted?

And I did hook a resistor to 12v and I have a signal reading on my device. What will changing the resistance value do to the reading? I have a 89ohm in it now and I have to tweak the output pulse setting to get it accurate when I crank...

thanks for the info!

Your image shows a rising edge signal, if it is now opposite to that then make sure the software has falling edge set.

The only difference the resistor should make (and I'm making an assumption that the input of the tacho is pretty high impedance) is the amount of current that flows through the resistor. If you have an 89ohm resistor connected to 12V that means that it will draw 0.134 amps. That means that it is trying to dissipate about 1.6Watts. Unless you have a very big resistor you will burn it out pretty quick. I would find something in the low 1000 ohm range.

Thanks for the explanation! I did have it set up right in the first place then. It was to be a falling edge sensor. I will change it back to that and leave it set as falling. I will also look for a bigger resistor and try that. Thanks again..

Hello DOOREV800,
The rising or falling setting of the ECU must match the signal you have going into the ECU. The correct procedure is to just wire the sensor to the ECU, if it is a Magnetic sensor (two wire) then you can wire it whichever way suits you. Next you would crank the engine with ignition and injectors disconnected and use the ref/sync capture to get a view of the signals. The ref/sync capture tells you how to set the rising/falling ECU parameter. If you have a rising ref/sync capture trace then you set it to rising, if it is falling in the ref/sync capture trace you set it to falling. There is no need to "try" different settings this is why we have the ref/sync capture application.

Noise Tr, Noise Ar are just warnings to tell you that the filters you have set are doing their job. These warnings WILL NOT cause any miss reading of the ref and sync and therefore cause no misfire. They are good to keep an eye on but nothing to really stress about. If your rising and falling parameters are set correctly based on your ref/sync capture then you should not change them ever.

MarkMc wrote:Hello DOOREV800,
The rising or falling setting of the ECU must match the signal you have going into the ECU. The correct procedure is to just wire the sensor to the ECU, if it is a Magnetic sensor (two wire) then you can wire it whichever way suits you. Next you would crank the engine with ignition and injectors disconnected and use the ref/sync capture to get a view of the signals. The ref/sync capture tells you how to set the rising/falling ECU parameter. If you have a rising ref/sync capture trace then you set it to rising, if it is falling in the ref/sync capture trace you set it to falling. There is no need to "try" different settings this is why we have the ref/sync capture application.

Noise Tr, Noise Ar are just warnings to tell you that the filters you have set are doing their job. These warnings WILL NOT cause any miss reading of the ref and sync and therefore cause no misfire. They are good to keep an eye on but nothing to really stress about. If your rising and falling parameters are set correctly based on your ref/sync capture then you should not change them ever.

Thanks Mark,

another question, under ign type setting-fall or rise- does the ref signal matter in regards to this setting or is this setting apply only to the coil type? I am using a ls2 coil and it is set to fall trigger. So if its a falling ref signal does the this setting follow suit?