Posted 15 July 2020 - 09:45 PM
Posted 25 July 2020 - 03:56 PM
Check for knock sounds in the engine bay. Loose exhaust, worn mounts, engine movement when suddenly WOT etc. which can trigger knock due to frequencies. Had knock on a R53 mini due to loose exhaust.
Logging sessions show that I was detecting knock retard when i had the standard exhaust system and the custom exhaust system. No parts of the exhaust system are touching chasis/body.
Logging sessions show that I was detecting knock retard when i had the standard engine mounts and the black series engine mount inserts.
Ive determined that when operating in WOT (open loop) i get more KR than when operating in closed loop (during fuel learning). So confusingly less fuel results in less KR.
Posted 25 July 2020 - 04:00 PM
Ive now tried a more viscous oil (10W60) to see if its piston slap causing false KR. It has made no difference to the KR readings.
Really struggling on where to go from here. Done another fuel learning session and the fuel table isnt changing much at all. Why is less fuel helping to reduce KR?
Posted 25 July 2020 - 04:25 PM
Posted 25 July 2020 - 05:07 PM
MoT limits for lamda are 0.97-1.03.
That’s at idle/fast idle not at WOT
Posted 25 July 2020 - 07:33 PM
What I have just noticed is that during the logging sessions at WOT the lambda readings are around 1.2. Correct me if I'm wrong but I thought that a lambda value greater than 1 meant lean conditions? Are these values correct?For a target AFR of 11.8 I was expecting a lambda reading of 0.8?
Lambda at WOT should be around 0.8 for an SC. If it's really 1.2 than it far too lean!
You did do a full fuel learning session? Did you also do a wideband learning?
Posted 25 July 2020 - 08:17 PM
The thing that’s confusing is when carrying out a fuel learn the fueling is in closed loop control and adjusting the injector duration based on the readings from the lambda sensor to achieve a lambda of 1 (14.7:1). In closed loop I’m getting reduced KR.
But when operating in open loop I’m getting a lambda of 1.2 (17.6:1) when trying to achieve a lambda of 0.8 (11.8:1). It’s almost like the correction of the fuel table for open loop control isn’t working right?
Edited by Fordy, 25 July 2020 - 08:25 PM.
Posted 25 July 2020 - 11:23 PM
Edited by TFD, 25 July 2020 - 11:24 PM.
Posted 26 July 2020 - 07:38 AM
Your 0-1V lambda dont account during wot. If your 0-1V lambda correspondes with your 0-5V widebandlambda (or vica versa) during normal drive, then you know your 0-5V wideband is OK. Use only your 0-5V wideband for wot/boost tuning, dont rely on your 0-5V lambda.
As I’ve mentioned before, I don’t have a wideband sensor.
The lambda sensor is showing that I’m running lean at WOT rather than rich. I don’t need a wideband sensor to tell me that
Posted 26 July 2020 - 09:36 AM
Posted 26 July 2020 - 09:50 AM
Tuning without wideband and relying on your narrowband...
Thank you for the response.
At this moment in time I’d be happy with a safe tune. Just because I don’t have a wideband fitted doesn’t mean that I don’t agree that it is the better option for tuning. Unfortunately, I’m not currently in a position to upgrade to obdtuner pro and a wideband kit.
At the moment I am trying to address the current issue with what I have. If you have any further advice it would be greatly appreciated
Posted 26 July 2020 - 01:03 PM
Apologies, I think I've realised why I've created some confusion.
Peter has corrected me that the lambda readings that I am seeing on the log files are the voltage rather than the calculated lambda value.
So, at wide open throttle I'm getting a lambda voltage of around 1.2 V which corresponds to a lambda value of less than 1 therefore there is indeed a rich mixture as there should be.
So it does seem that i'm getting KR with rich conditions.
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