[jvanabra]

My 16v c900 Won't Start

Here's a flowchart describing how the c900 starts:

Here's a breakdown of the TSI socket, which can be useful in diagnosing start problems:

 

[Jim Mesthene]

The Hall Effect Transmitter produces a square wave.

 

[jvanabra]

Ah, fair enough. Hall Effect sensors are analog devices, but the conditioning circuit could be built into what's in the dizzy rather than in the ICM. Makes sense - I will update!

 

[Rodentmaster]

The shape is square directly out of the hall sensor. The cutout on the crank (or dizzy rotor) dictates the primary composure of output. EZK or ignition module sharpens the shape via Schmitt trigger logic gate/s.
For your flow chart, may I suggest the Tacho be off a split to the side of the ignition stage?.......not through.
LH and tacho share a common tach input.
The flow depicted suggests the signal flows through the tacho (which could infer a possible point of failure) ??

 

[jvanabra]

Hall sensor makes sense...

I'm not really approaching this as a flow chart per se, but rather a "points of possible failure" approach. As indicated, there is a splice behind the tachometer that sends signal to both the gauge and the LH ECM. Maybe call out that splice and send one leg to the tach and the other to the ECM?

 

[Rodentmaster]

...yep ...a splice point or a "T" joint would give the better concept or birds eye view of the signal path if a newbie was to be reading for the first time.

 

[jvanabra]

Updated!

(BTW, SaabCentral's auto aggregation of images is both great and super annoying... you cannot replace images of the same name. Grrr.)

 

[jvanabra]

Final update.... IT'S A MASTERPIECE!

 

[Jim Mesthene]

I found another nit!
No Neutral Safety Switch?

 

[jvanabra]

Ah, yeah, the little orange wire. Do you know offhand if it's + or - that triggers the interlock?

Edit: No, not the orange wire. That thing is the idle increase for D(rive). (Or, the I'm teaching someone to drive a stick and need a few more revs at idle )