My LTFTs are perfect, but I had a weird STFT reading in the same 2 cells, over my last several logs. What's really strange is the STFT readings have been very close to the same reading on each log and my LTFTs for those same cells are within .2% error. Is this likely from transient fueling? If so, how would I tune this out?
Last edited by txcharlie; 10-23-2015 at 12:08 PM.
After looking at the logs more closely, I found some common elements, but I don't know what's causing it.
1. For whatever reason, every time it spikes lean on the log, in the specific MAF periods, the LTFTs flat line to 0 just before and while it happens.
2. Fuel Source is always CL Stoich.
3. Throttle Angle is ~20*
4. More times than not, it using MP 9
I understand why my LTFTs are good and STFTs are not. I can't figure out what causes the LTFTs to flat line.
Not sure if this is your issue but when my car was on the dyno it was doing close to the same thing and it was 2 bad widebands/upstream o/2s they would read fine every where except one point in there range changed both 02s and it went away
I hope not. Car only has 8500 miles on it.
Same here, 10K miles, just did a long log tonight, glancing over I saw this happen some. If I remember correctly I saw this pretty consistently in older logs too. I will have to go back over the data and see. I know our coyote kit car exhibited much more consistent behavior. As soon as LTFT's came online, bam! STFT's go back to zero. This might be due to the control pack tune being not quite as dynamic though. Not like the car drives weird or has strange wideband readings. It's not the end of the world though if they are bad.
My car only had 4000 miles on it at the time sounds like a different issue for you though
I'd say it probably has to do with not being able to tune VE and baking everything into the MAF. Some load/pedal/RPM/MP combination gets a dose of wrong VE and the STFT react while the LTFT still correlate to the before and after.
That makes sense. I don't know too much about it, but VE tuning seems a lot more comprehensive.Originally Posted by Higgs Boson
So it seems, with the tools we have, there's not much we can do.
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