Smiths Flight Electronic Tachometer

v8250 · Post by **v8250** » Wed Jan 20, 2016 10:22 pm

Gents, looking for a sanity check here. Installing Smith Flight/Prism Electronic Speedo and Tacho' in the BV8 conversion [TVR 4.0 with 14CUX]. The tacho' needs input from -Ve side of coil as per norm'. However, the ECU also has a link from the coil to pin39/white black wire :.

Q? does the 14CUX ECU need the coil signal to operate fully...or, can I ignore the ECU wire and just connect -Ve coil to tacho?

And depending upon answer, I'll ask why...?

DEVONMAN · Post by **DEVONMAN** » Wed Jan 20, 2016 11:39 pm

The ECU needs a signal from the coil so that it can fire the injectors to suit engine speed etc

v8250 · Post by **v8250** » Thu Jan 21, 2016 8:23 am

Thank you Devonman, that's just the answer. Had been trying to find the data on this and couldn't find it anywhere. Have the 14CUX diagrams and operational manual but the only data was the engine speed sensor with 6.8k resistor test. Rgds, Andrew