Ideas to use a 3rd party rev counter with any modern FIAT

[lewey]

There are very few ways to wire the canm8 device wrong and it just doesn't work for me. The "ignition on" should be very easy to identify, but it doesn't work. I don't have any choice but to return it. I tried a pull down resistor with the tacho output, with no effect. I did try revving the engine a bit with each experiment, in case the counter was reading low.

Looks like I'm going to be looking at diodes utilising the coil-per-plug triggers. Good point about 2Hz per revolution. Funny how you forget the basics when your held is filled with new stuff.

 

[petrolhead69]

Have you tried scoping the canbus from the ecu? Maybe it doesn't want to talk to the canm8 without the can gateway controller from the bravo.

 

[EI4GGB]

Have you tried scoping the canbus from the ecu? Maybe it doesn't want to talk to the canm8 without the can gateway controller from the bravo.

good point, not being very familiar with the new bravo's, where does the gateway live ?. If its in the body computer then it should be working, but you would want to be connecting at the diagnostic socket CAN lines. he didn't say where he was connecting it. very hard to see whats going on after that unless you start analysing bus traffic. Anyway, since only the RPM is needed, the simpler solution should work.

 

[lewey]

good point, not being very familiar with the new bravo's, where does the gateway live ?. If its in the body computer then it should be working, but you would want to be connecting at the diagnostic socket CAN lines. he didn't say where he was connecting it. very hard to see whats going on after that unless you start analysing bus traffic. Anyway, since only the RPM is needed, the simpler solution should work.

Although I returned the unit a while back, I have now got the instructions which I have attached. It mentions your point about connecting at the right point, i.e the OBD interface wires. That was almost certainly the issue for me. I am going to have a go at wiring up the tacho from the coil trigger wires, but if I fail then I might go back to this solution.

 

[lewey]

To follow this up, I got another unit second hand and plugged it in the right place and it still doesn't work. It may be compatible with some Bravo electronics, but not mine.