pulse signal

bad driver · Unread post by **bad driver** » 17 Oct 2004, 01:47

anyone know how I can find a pulse signal on the 306 td?
basically the td engine is in a n/a derv, the n/a didnt have a tacho as standard and I got fed up off dodgy incorrect speedo on cable drive so I'm putting aftermarket gauges in but the tacho requires a signal, assuming the engine will be sending one as the dt had a tacho and they use the same loom. Also need to find out if it is 2 pulse??
Thanks
Richie

PowerLee · Unread post by **PowerLee** » 17 Oct 2004, 01:56

Hi
It all depends what set of gauges your fitting to your 306.
There are several different options for a start, At least one of the diesel tachos works of the alternator terminal W, All the other diesel tachos work of a engine sensor, I think its the TDC flywheel sensor but dont quote me on that.
Also mid 1996 was the changover point for ditching the speedo cable for the electronic set up.

PowerLee · Unread post by **PowerLee** » 17 Oct 2004, 02:01

Hi
I would look for a Brown 3 terminal plug near where the gearbox & engine are joined.
This is the flywheel sensor connection.
Have a search on the Citroen section for "Diesel Tacho" & that should point you in the right driection

bad driver · Unread post by **bad driver** » 17 Oct 2004, 02:26

Thanks for the quick response, I've had a look and search etc, anyway, I know of this TDC sensor, mine comes up to a 2 pin plug though?? Also I think it may need replacing as it appears to be dead as a dead thing. should it make contact with the flywheel? Mine seems to have a small gap between it and the flywheel. I'm also assuming as its a TDC sensor it will only trigger once per revolution when the engine is at TDC, any idea what would happen if I could make it trigger twice, the tacho requires a 2 pulse connection, which I am assuming means 2 pulses per revolution.

bad driver · Unread post by **bad driver** » 17 Oct 2004, 02:36

The alternator is a good theory, any idea what the ratio per revolution is on there? ie 2:1 ??

PowerLee · Unread post by **PowerLee** » 17 Oct 2004, 15:01

Hi
The flywheel sensor should have a small air gap between the tip & the cars flywheel.
There are loads of small notches around the flywheel & one large notch, The sensor works just like a ABS sensor by sensing the notches passing under the sensor, The large notch is the reference one so the sensor knows when 1 complete revolution of the engine has occurred.
I do know that diesel tachos are different form petrol ones & cannot be swopped between cars.
I cant really help anymore on this subject, Im more of a petrol man.
Im sure somebody has done this before, good luck.