Knock Light Implementation
Knock Light Implementation
I read the title of another thread and thought it was about creating a knock light function with the Xede...
Assuming one has the SMART system it occurs to me that one can program the water spray output to permit turning on the MIL when knock is detected by setting,
Control source = an0in
RPM >= 3500 (this is arbitrary but seems like a good number to start with)
Control >= 40 (my experience suggests that this would filter out random junk)
Once started stay on for = 5 (again arbitrary, but one would like to see the problem)
Stay off for = .1 (something minimum)
Then the water spray output of the Xede can be tied to the MIL light at the ECU, as ground the pin at the ECU turns the light on. This works as the Xede ground the water spray output when the function is active.
Note that I haven't tested this but its a good bet that it would work
Assuming one has the SMART system it occurs to me that one can program the water spray output to permit turning on the MIL when knock is detected by setting,
Control source = an0in
RPM >= 3500 (this is arbitrary but seems like a good number to start with)
Control >= 40 (my experience suggests that this would filter out random junk)
Once started stay on for = 5 (again arbitrary, but one would like to see the problem)
Stay off for = .1 (something minimum)
Then the water spray output of the Xede can be tied to the MIL light at the ECU, as ground the pin at the ECU turns the light on. This works as the Xede ground the water spray output when the function is active.
Note that I haven't tested this but its a good bet that it would work
I don't think so because...
The MIL light is activated by the ECU via grounding the light within the ECU. In other words the other side of the light is +12v. Thus by connecting the Xede's water spray output to the ECU MIL light pin, either the Xede or ECU can activate the light (e.g. wired or).
Futher as the Xede would only flash the light when knock is present versus when the ECU activates the light it is on until reset, one can tell the difference between knock and when the ECU throws a MIL condition.
In short one can get this functionality by simply adding a wire from the Xede's water spray output to the ECU MIL pin. Then simply change the Xede's water spray conditions as cited above.
Basically I'm 90% sure this will work. The only question is if the Xede will respond to the short pulse represented by the knock condition. If the Xede doesn't process the water spray conditional every at the normal 100 hertz, then it might miss a knock state. That is really the only question on my mind at this juncture.
If someone is interested in this I could document this further or push a bit testing it with fake data (e.g. set to trigger at a lower threshold, or engine noise).
The MIL light is activated by the ECU via grounding the light within the ECU. In other words the other side of the light is +12v. Thus by connecting the Xede's water spray output to the ECU MIL light pin, either the Xede or ECU can activate the light (e.g. wired or).
Futher as the Xede would only flash the light when knock is present versus when the ECU activates the light it is on until reset, one can tell the difference between knock and when the ECU throws a MIL condition.
In short one can get this functionality by simply adding a wire from the Xede's water spray output to the ECU MIL pin. Then simply change the Xede's water spray conditions as cited above.
Basically I'm 90% sure this will work. The only question is if the Xede will respond to the short pulse represented by the knock condition. If the Xede doesn't process the water spray conditional every at the normal 100 hertz, then it might miss a knock state. That is really the only question on my mind at this juncture.
If someone is interested in this I could document this further or push a bit testing it with fake data (e.g. set to trigger at a lower threshold, or engine noise).
Originally Posted by donour
Good idea, but wouldn't that disable the MIL's "legitimate" uses?
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MIL is the name that the SAE gives to the light in their official specs. People (and automotive companies) call it lots of different things, but in the actual OBD-II documents it's MIL.
And for future reference, ecu codes are called DTCs (Diagnostic Trouble codes). We usually only talk about the powertrain ones (Pxxxx), but theres also a an entire set for transmissions and chassis malfunctions.
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And for future reference, ecu codes are called DTCs (Diagnostic Trouble codes). We usually only talk about the powertrain ones (Pxxxx), but theres also a an entire set for transmissions and chassis malfunctions.
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Sure but then you would need to find somewhere to mount the LED.
couldn't you get the same effect with a LED
In any case I'll write up instructions this weekend and post it.
Originally Posted by NEMES!S
couldn't you get the same effect with a LED