Data file, troble with PLM readings.

[Chris Wilson]

Would someone kindly have a peek at my logging file taken at Oulton park from my RB26 engined RWD Skyline please? I am happy with the mapping, it has done several track days with no issues. I run dual wide band Lambda, one is read hard wired to the M800, the other via CanBus from my PLM. On Saturday the PLM started to show Lambda of over one at times, which it has only done before when I lost an ignition igniter output and the engine was on 5 cylinders. I THOUGHT I had logging set to record both sensors, but my mapper who did some map trimming last time out may have reset logging to suit his needs at the time, so I am unsure if I am reading the log incorrectly or not. It seems to show Lambda 2 as an error in the right hand column. I believe Lambda 2 is the sensor on the PLM, and Lambda 1 is the sensor that the M800 reds directly and is used on its own for the map trim? The log for Lambda 1 seems, to me, to be showing safe and sensible O2 levels, which is good. So, finally, my questions are, is there a fault with Lambda 1 sensor? Should I try re calibrating it? Or is the data logging set incorrectly to show this area of functionality? I am happy to post the map if needed. thanks. http://www.gatesgarth.com/oulton.zip

[MarkMc]

Hi Chris,
From the logging and the configuration file it looks like every thing is set up correctly. It may be a CAN bus wiring problem. Are you sure the PLM's sensor was working properly?

[Chris Wilson]

Thanks for the reply Mark. On 4 previous occasions the Can Bus wired sensor (Lambda 2) read the same, near as damn it, as the hard wired Lambda 1 sensor. It was this last day where I was aware of any issues due to the reading on the PLM suddenly going worryingly weak, usually at idle and manoeuvring, but sometimes under boost, which grabbed my attention I will check out the wiring on the PLM and Can Bus, and if that's OK I will change the sensor. Should I enable further logging of Lambda 2 for now, to see if it throws more light on the subject, or can you not log much via Can Bus? Thanks again.

[MarkMc]

Hi Mate,
Nothing wrong with putting the PLM through the CAN bus, my car has been like that for years. If the PLM shows silly lean figures at idle then seems to almost come good when the engine is under load it is a sign the sensor could be on its way out.

The logging you sent shows no lambda value at all but the ECU is setup correctly to recieve Lambda from a PLM via CAN.

Fire the engine up with the laptop connected to make sure the PLM reading and the ECU channel from it are reading correctly and possibly swap the hard wired sensor into the PLM and the PLM snesor to the ECU to see if the problem follows the sensor or the PLM.