Does anyone know if a 94 e350 will have a cto tach wire anywhere? Looks like newer trucks had one coming out of a harness by the break booster. I'm building a tach from a microcontroller, and this signal would be easier to process than the raw signal off the ip. It's an automatic, so the sensor is there for the trans, just trying to find a good place to pick up the signal for my use.
CTO wire
- Thread starter lkrasner
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ifrythings
Full Access Member
There is no Clean Tachometer Output on these trucks, being you have an automatic you can grab the tach signal from the TECA to tachometer as it will be a buffered signal from the tach sensor.
Do note that this signal from the TECA isn’t the nicest looking and will be a very high pulse train (54 pulses per rev if I remember right), if you have a tachometer in your van you can copy the input op-amp circuit that they use which will give you a clean square wave that you can feed to your micro or you can tap off of the output of the tachometer op-amp and use that.
Do note that this signal from the TECA isn’t the nicest looking and will be a very high pulse train (54 pulses per rev if I remember right), if you have a tachometer in your van you can copy the input op-amp circuit that they use which will give you a clean square wave that you can feed to your micro or you can tap off of the output of the tachometer op-amp and use that.
There's no tach in it currently. Where can I tap into that signal. Doesn't need to be thay clean. Thinking I can clamp it with a 5v zener diode to drop anything over that, then counting 54 pulses / Rev should be easy even if it isn't clean, as long as it has a reasonable rising edge. I can throw in a Schmitt trigger inverter or something on the input if it's too dirty, but as long as I get to a reasonable square wave it shouldn't be an issue.
ifrythings
Full Access Member
Pin 36 is the tach output, red with a light blue stripe, this may also be at the instrument cluster too.
Note: the wire maybe a different colour as I forget what year this diagram was for.
Note: the wire maybe a different colour as I forget what year this diagram was for.
Or just pull it off the alt output?
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