- Woke up with an idea of what was causing the WOT problem from yesterday. Cut a long story short, the AFR being delivered to the MegaSquirt ECU from the TechEdge wideband controller (Model 2Y1) was jumping erroneously all over the place. The clue was yesterday when I noticed at times that the AFR meter in the TunerStudio application was pinging up to 19:1 AFR (very lean).
This morning I connected up a logging application directly to the Techedge to monitor the AFR directly, and also I monitored the AFR in TunerStudio. There was at times a fairly large discrepancy. I then applied the age old t
rickmethod I used to use ages ago in testing ‘microphonic’ valve equipment when I was in the R.A.A.F. i.e. I gave it a knock, the TE that is. The AFR stayed steady on the TE but went ballistic on the MS. Mmmm… found my problem but where? I then grabbed the two wires feeding the MS and you guessed it (well did you?) the earth wire fell out of the connector.
After screwing it back in, the AFR’s tracked within 0.2 – 0.3 AFR, (the difference is mainly down to slightly different ground voltage levels), of each other. Yeah problem solved.
- Yesterday I also mentioned that I might try 2 squirts instead of 4 squirts per cycle. Well I tried it, and after slightly modifying the VE table, so that it would run, I decided to go for a drive with the TS autotune function doing its thing. So far OK, then I had to stop for some petrol. Upon starting the engine went into demon mode! It sat there cycling up and down around 2000 RPM. Turned off ie recycled the ECU, still no go. WTF!
Changed setting back to previos 4 cycle, recycled and back to normal.
I don’t know what the problem was, will look at further down track.
- I also updated the MS ECU firmware this morning.
- Took it for a drive to autotune the VE table, goes very well, the WOT problem has nearly gone, the logs I took still show that I’m running out of duty cycle i.e. can’t put enough fuel in when hitting the gas pedal abruptly. Maybe the acceleration enrichment demands are to much now since the AFR has been fixed?
- Car has a very small oil leak. Bugger! Looks like its around the back of the engine or timing cover. Does anyone have a fool proof way of telling from where?
That’s all for today, and maybe a few days or so as I’m back to work tomorrow, Bummer!