Converting CSV files to LogWorks format

beetle wrote:

czen wrote:

What I want to understand is: what exactly does the AFR log on the Scan M5X actually record?

You'll need a wideband sensor and controller. You'll have to either feed the analogue wideband output into the ECU or via HC-06 directly to ScanM5x. Logging the narrowband via the ECU will be pointless.

Yeah - been reading up on this today (also got an e-mail from Christian, the guy who put together ScanM5X) and that's the overall conclusion.

Doing a wideband installation is a bit more time/effort/cost than I can handle right now.

Still, is the narrowband totally useless even for determining if you're running too rich or lean? Guess you could look at your spark plugs too - but is a narrowband log not of any more utility than that?

The narrowband trimming is primitive in its approach. The narrowband sensor, to put it simply, has three states: Rich, Good, Lean. The ECU doesn't know the magnitude of the rich/lean state. Say the sensor output sends 'rich'. The ECU has a look-up table, and trims by a preset value. The sensor sends 'rich' again, so the ECU trims again. Then the signal may be 'good', so the nothing more happens. At another point, it may send 'lean', so the ECU adds a bit. It's an iterative approach, and the throttle must be in a steady state for a long enough period for the ECU to trim to the 'good' point.

Unfortunately, the 'good' point is not really that good. It's usually a small range with the stoichometric point of 14.7 smack in the middle. Great for meeting emissions standards, not so good for lean best torque.

Truth be told, using a wideband device, whether it be a fixed sensor or in a dyno, is really the only way to get your AFR right. Second best is looking at the plugs. Reading the plugs is still a valid way to do it, but you end up with a compromise.

The narrowband log will just be a number that has no meaning. It may as well be counting house numbers.

If you don't want to invest in a wideband setup or some dyno time, may I suggest turning off the lambda in the map and read the plugs and use seat of pants.