[PSIG]

The intent is to prevent the sensor from sitting at full pre-heat and full temperature before engine start, where cold engine condensation could cold-shock the sensor element. Typically, the relay for WBO2 power would be triggered with the ignition coil or fuel pump power, and it is common to simply take power from the pump relay output.

If you wanted to get really picky, you could set an AuxIO function to be active above cranking rpm threshold, on its own relay. I wouldn't get that picky myself.

[MikkoR]

Ok. Maybe it's a wise choice to leave it unpowered during the first start attempt to eliminate full heat before engine start. You may have to crank and crank and crank before the engine starts... if it starts...

[Roverdog]

On the subject of WBo2 power supply,don’t pick it up from the pump supply.i have been chasing rpm spikes when cranking for a while on my install with a 36-1 & Ford VR sensor on a Rover V8.
Finally traced it with scope to fuel pump noise somehow causing massive rpm spikes via the 14point7 power supply which i had sourced from the fuel pump feed.
When running it was ok so i surmise that the speedy noise filter was not quick enough to deal with it when cranking.
Anyway,sourced wb power via pump switched relay,problem solved.

[PSIG]

Anyway,sourced wb power via pump switched relay,problem solved.

Thanks for reinforcing this small (but important) point. The actual WBO2 power is not pulled from noisy coil or fuel pump power, but rather the power is used to signal the WBO2 relay, as I stated above:

… Typically, the relay for WBO2 power would be triggered with the ignition coil or fuel pump power, and it is common to simply take power from the pump relay output.

[MikkoR]

Engine wiring harness is ready. Well, a couple of outputs still unconnected (fan etc.), all wires are connected which are needed for starting the engine. At the moment I'm missing a valid M20 tune. I found some tunes, perhaps from my previous M20 Megasquirt project, but I have no clue if they are valid or just some rough examples...

Anyone has a running tune for M20? A tune with all basics set correctly, just for trying to get the engine start and run.

https://photos.app.goo.gl/bqRoLQv8dB7GrCW99
https://photos.app.goo.gl/JFHGKczoSrmBNgux5

[MikkoR]

Ok, created a tune. Speeduino connected, at this point the goal is just get the engine running. At first I just cranked and checked what's happening. Some fuses disconnected to proceed step by step, starting from fuel pump. Result: fuel pump is not running. Pump itself is ok, it's running when powered.

- IAT value ok
- CLT value ok
- TPS calibrated
- When cranking RPM gauge shows some reasonable values -> trigger wheel ok -> possibly also sparking. Coil fuse is however disconnected
- When cranking Duty cycle gauge shows some reasonable values (about 10%) -> injector control maybe ok. injector fuse is however disconnected

So far so good. But fuel pump pin has no current. The pump is controlled by relay and relay is controlled by Speeduino FP pin. The tune has 3 seconds FP run when power-up, no current in FP pin... Or is it grounding pin?

Any ideas? Would it make sense to get the relay control from ignition switch, just like the coil?

My tune is based on TPS, do need to attach a vacuum hose to MAP?

[LPG2CV]

As you suspected, FP relay ground, goes to FP pin on Speedy.

And yes, switched 12v to FP relay

[MikkoR]

Ok, fuel pump is now running as it should. But, I'm a bit confused aboout trigger angle.

"This number represents the angle ATDC when tooth #1 passes the primary sensor."

In the picture the engine is in TDC and engine rotation is clockwise. So, as far as I've understood, the trigger angle is 45 x 6 = 270. Also (43 teeth plus missing two) x 6 degrees. In case the tooth #1 is the first tooth after the gap...

[LPG2CV]

That appears to be in the ballpark.

Disable fuel, lock timing to zero, set cranking to zero. Confirm it with a timing light. Adjust TA until marks line up at TDC.

[MikkoR]

I tried this today. All set to zero, additional wiring done for cranking the engine while standing in front of the car.

Cranking, but no flashes in the timing lamp. Lamp tested in another car, lamp is working. Another try, no flashes - except a couple of flashes just when releasing the cranking button.

So, no spark while cranking, but got a couple of sparks when stopped cranking and the engine still rotated a bit. I ran out of time, but I suspect that I've taken the coil relay control from a wire that is not "Hot in run and start". It would make sense, however, if this is not the case, then I don't know.

We'll see...