Voltage of rpm signal from ECU?
08 June 2006, 09:36 PM
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Voltage of rpm signal from ECU?
I want to log the RPM along with AFR and MAP in tewblog, but I'm not sure wich setting to use for the J4 jumper. It seems it should be the 2-3 (LO/RPM) setting which takes a 5 volt pulse. But after searching scoobynet it seems the pulse from pin 14 on plug B135 is a 12 volt pulse. Is that true?
Surely someone on here have logged these values in tewblog? How did you manage to do that?
Oh, it's a MY99 if that helps.
Surely someone on here have logged these values in tewblog? How did you manage to do that?
Oh, it's a MY99 if that helps.
08 June 2006, 10:52 PM
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Yes, it is a battery voltage pulse. Not used tewblog to log it, but I have fed it into a microcontroller with a series resistor and a clamp diode and then the microcontroller just read it as a logic (5V) level. I daresay you could do the same, but most RPM signals I would think are not logic level.
You can also get a signal from the feeds from the ECU to the ignitor module, although they are divide by two as one of these would pick up two rather than all four cyls.
You can also get a signal from the feeds from the ECU to the ignitor module, although they are divide by two as one of these would pick up two rather than all four cyls.
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