adrial

What style crank trigger does the 968 use? As far as I know, its not the same setup the 944 uses.

I've heard its a motronic 60-1, but I am looking for confirmation.

thanks,
Adrial

theedge

Yes, standard Motronic 60-2 (note the 2 there!). Its mounted on the flywheel. There is also a cam trigger.

adrial

What's the cam sensor for? Does the 968 run sequential or direct fire? I can't see how it would be neccesary for anything else.

hauser

The 944s run two reference sensors the 968 runs one reference sensor and a hall sensor on the back of the cam pulley, and not sure why but it would be nice to know!

Mikes3.0cabturbo

the hall sensor is for the knock control so has to know TDC, CPU needs more than just the crank sensor to do this

FRporscheman

OOOOooooohhh. Good to know.

adrial

The crank sensor, being a 60-2, should tell the ECU where TDC is...

The cam sensor is generally needed to distinguish an intake cycle from a combustion cycle, so that fuel is only delivered when it's needed (sequential fuel injection) instead of every cycle (batch fire).

Mikes3.0cabturbo

the 60-2 crank signal is generated every 360 degrees, the engine cycle is 720 so the CPU needs the cam trigger to know exactly where it is in the engine cycle otherwise it doent know if its top of exhaust stroke or compression stroke TDC. Your right that this camshaft sensor is used for sequential injection and spark/knock control.

hauser

I believe its also there because of the variocam, to send the correct tdc signal to the dme.

Mikes3.0cabturbo

I thought the variocam was a RPM driven function, so it would need some smarts to look at rpm then generate a digital on/off signal that would be via the CPU, which could derive rpm from either the crank or cam sensors.