I imagine it is the way the XDi unit 'clocks' the TDC via the 2 missing teeth on the crank pulley wheel.
The missing tooth gap is clocked by the crank sensor when the crank rotates and the count then starts. The command to spark to a given set of plugs in the firing order than commences.
You could do the same using the cam shaft, just the timing count is 1/2 the crank speed. However, the XDi needs about 900 rpm to find the crank position.
It is this bold simplicity of the (2005) XDi system that appealed.
They have made these for a lot of years, I know to 3 in England, all 6 plug 911 engines, and all fired up straight away. All 3 running mechanical injection. One has been running untouched since set-up for 10 years.
Today:
Interesting day on the Lola today.
Ran the XDi box's grounds direct to the battery (helps kill some noise)
The crank sensor is removed and the loom modified for the Hall sensor that's coming.
Emailed the starter motor supplier, Brise, yesterday and they have replied. Not a known problem but they want to know how I get on (
)
A suggestion is to add a dedicated earth cable from the starter to the battery ground direct.
I have been through the entire installation.
First was to machine a small tool turned to push directly on the female terminals in the 23 way connector.
No terminals push back (ie when you push the 23 way connector into the XDi box).
All wires in the right pin location ticked-off in the manual, so all good.
The jumper lead added for the Hall sensor coming (linking pins 4 & 5 together) in the 23 way plug.
All power leads (3) belled through from the +ve battery terminal to the XDi box and the two coil packs.
All grounds tested good.
The closest the crank sensor cable is to any of the system on the engine is 10".
Inevitably, the lot all come intimate at the 23 pin plug.
Electromotive have not given me a FedEx tracker ( :roll: ) so have no idea if it is on it's way or gone to the moon.
Clewett has stopped answering emails.....
Emeralds ECU people enthusiastic, Megasquirt Dealer very energetic! DTA still there waiting.
I really cannot see where there is a flaw in the installation.
End of next week might be interesting.