Wire with Power only when the Engine is running/starting?

Posts specific to the 2.5 litre turbo engine

Re: Wire with Power only when the Engine is running/starting

Postby tom_kauf » Mon Jul 03, 2017 2:19 pm

The result is what I was after doesn't exist. Pages 1243 onwards of the Service Manual (EN(H4DOTC)(diag)-17) nicely list all the ECU outputs with Engine Off (Ignition On), and Engine On. None of them are usable for what I'm after. Even the factory O2 sensor heater relays don't get steady power with the engine on, they get a 'Waveform'.

I had even removed the cabin fan assembly to get to the 'Main Relay' on the passenger side. It only got a few volts DC (maybe because it was actually a waveform, and not a steady voltage) - I didn't get out the old oscilloscope to look at it.

So my solution: I made my Windeband O2 Sensor into a mobile unit. I put a bung in the top of the Dump Pipe's sensor location, so it's removed for everyday driving. Then every few months when I do some logging, I re-insert the Wideband into the Dump Pipe. Then connect it straight to the battery and go for a drive.

The alternative would've been to get an AEM Wideband Unit, which don't blow their sensors. But I have a booking on the Dyno in 7 days, so that's pushing it. And I only just bought a new Sensor for the Innovate Unit, so it'll last a while if I only use it occasionally.

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