Megasquirt P38 range rover sensor sharing - Continued from previous page

With the Megasquirt correctly configured the next job was to splice into the existing signals going into the GEMS ECU. Because I already had a spare loom, I could make up little splice connectors. You simply push the pin out of the connector and insert the splice - totally non destructive and neat.

And here’s the proof that it worked.

The blue boxes are the values read in from the GEMs ecu using my Blackbox Faultmate Diagnostics for the P38 and the dials are the values that megasquirt see - as you can see, dead on.

Throttle posistion was just tapped into and then I used the TPS calibrate function in tunerstudio(or megatune) to set the closed and wide open positions.

Startup

I finally found a use for my round headed long nose pliers - they allow you to get to the injector connectors under the plenum inlet.

I had a known good base map already which I had adjusted a few parameters (edis etc) and the car pretty much started up straight away and idled smoothly.

I took the car for a few miles drive and it felt really nice. Amazingly no engine check lights on the dashboard, despite the ecu logging an open circuit fault with all 8 injectors.  

So I have Megasquirt controlling fuel and the GEMS controlling spark, idle and everything else.

I’m really pleased with it so far. Next step is getting a wideband fitted.

29/6/2011 Update

Done around 250 miles with no lights or errors at all.

I removed one of the Narrowband lambdas (pre-cat) to fit a Bosch wideband lambda - still no check engine lights.

And now I’ve removed the Mass Air Flow meter and still it works without protest!