MicroSquirt (3.3) Questions. Green. CAS & CAM

[BrokeRabbit]

Noob, green, whatever you want to call it, I am IT!

The engine is a VW 16v head mated to a 2L ABA bottom. Microsquirt V3.0 as supplied w. harness from DIYAuto

Regarding the CAS/Engine Speed Sensor.

The ABA engine speed sensors (CAS) has three connections.

• Red - Sensor ground at ECU (Motronic)
  Green - Sensor signal
  Black - Ground connected at engine compartment and connected to shielding

VR1+ and VR1-. I assume + goes to the original “green” and - goes to the “red”. The question I have is the ground. The shielded grey cable has the wrapping foil and a bare wire. Should this bare wire be connected to the “black” wire from the OEM CAS and should I then run a separate ground wire from there to the chassis? Hazy on this detail since the bare wire is not connected to anything at the harness connection to Microsquirt.

Best practices question. With the VW ABA bottom end, I am using the stock CAS. The OE ring at the crank is a 60-2. Should you start with the 1/4w 10k resistor or is that for truly high revving engines only?

Regarding the CAM position sensor

The VW 16V distributor is the hall/optical trigger type I believe (falling edge). Should that be wired up to VR2+ and - or OPTO+ and -? I’m inclined to say OPTO based on the description in the manual. If that’s the case the damper on the block does not have the convenience of timing marks as demonstrated in the manual. Is there another method?

How does the wiring work since I have:

• Ground
  Signal to ECU
  Shared voltage supply with injectors, etc

Thanks in advance.

[prof315]

Use the ABA crank trigger with a 10K resistor. Don't bother with the 16V distributor it will require mods to use it as a cam sensor and you can't run sequential fuel on a microsquirt anyhow. The ABA 60-2 crank trigger will allow a wasted spark ignition along with semi-sequential fueling. As far as the rest goes

[BrokeRabbit]

The ABA 60-2 crank trigger will allow a wasted spark ignition along with semi-sequential fueling. As far as the rest goes

Thanks! I did some research after posting the topic up and landed on wasted spark using a 2L ignition coil I have laying around. Appreciate the help.