Tacho question

[UIL9794]

Hi Guys

Does anybody know if the tacho on the Chims is connected in series with the coil or paralell?

Lee

[nemery]

Fairly certain it will be in parallel - you wouldn't want to put all the coil current up through the tacho and all the way back down to the coil.

[UIL9794]

Thats what i would expect but i have seen somewhere on the wedge forum that they were in series - the guy could'nt start the car with the tacho disconnected, when it was reconnected it started.

The reason i'd asked was because i had had a few starting problems and since changing the plug extenders the tacho reads about double what it should be then sometimes it reads about half!!
Thanks
Lee

[griffter]

isn't it more likely that the 'feed' for the tacho also feeds the rpm signal to the ECU?

[shpub]

UIL9794 said:

Thats what i would expect but i have seen somewhere on the wedge forum that they were in series - the guy could'nt start the car with the tacho disconnected, when it was reconnected it started.

They are in parallel. Wedges also have different versions of the engines and wiring and ECU.

If the tacho is double reading etc then the ignition system is screwed up or there is so much interference and generating additional peaks that are being counted and thus causing the readings.

>> Edited by shpub on Friday 31st October 09:53