looking into an aftermarket ecu for my cinq as a little project.

most of it makes sense so far, apart from 1 item i am struggling to understand!!

the RPM signal wire from the ECU; from what i have read it is pin 23, yet all wiring diagrams i can find show pin 23 as being a coil wire on the fuel pump relay?

could someone please enlighten me on this please? thanks

Bump, surely someone knows the answer to this?

I fitted a Sporting instrument panel via the guide on this forum:
https://www.fiatforum.com/cinquecen...90-how-fit-rev-counter-cento-without-one.html
It worked fine. I picked up the rev counter wire from pin 23 of the ECU (a purple/black wire at the fuel pump relay is a convenient point).
I have no idea if this will work with third-party rev counters though. Hope this helps.

I really wanted to confirm the wiring diagrams I have as I have seen the info you are on about, but in the haynes manual and other wiring diagrams I have seen, the wire from pin 23 goes to the coil of the fuel pump relay?

Before I look at ripping the wiring out for an aftermarket ecu I wanted to find a decent wiring diagram that actually makes some sense!

I changed the "simple" panel to the panel from the "sport-version" which have a RPM-meter. I only has to connect the pin23 to RPM-meter and it was ok like that.
As i understand, the pin23 signal is the ac-voltage with the frequency of RPM. It need to be so for security reasons - the ac-relay for, for example, fuel pump will stop it when the engine is stoped.

ser907 said:

I changed the "simple" panel to the panel from the "sport-version" which have a RPM-meter. I only has to connect the pin23 to RPM-meter and it was ok like that.
As i understand, the pin23 signal is the ac-voltage with the frequency of RPM. It need to be so for security reasons - the ac-relay for, for example, fuel pump will stop it when the engine is stoped.

Click to expand...

done a bit of reading up on it. makes sense now. learn something new every day. didnt realise such a thing existed, but makes sense why it is used. the wiring diagrams dont make it obvious.

thanks