Using Alpha Fuel learn to Verify K constant

[skidder]

Hi All,

Right im trying to use the alpha fuel learn to validate and adjust where appropriate the K constant.

So I have a SR20DET, 555's nismos, z32 Maf, GT2860 disco potatoe, 3" manifold, elbow and exhaust.

So im looking at the fuel learns in the consult gauges. Just want to be clear I'm interupting them correcty.

We have:

AFR Alpha
AFR Alpha learn

Can any one clarify what the above means? I assume these are STFT and LTFT? According to the gauges the range is -50 - 150 so i assume 100 is the place to be at?

A number less than 100 means removing fuel? A number more than 100 means adding fuel? Hopefully someone can confirm for me how this works. Seems like a nice easy way to validate k Constant assuming my NB02 is working nicely

Also can anyone confirm what the latency should be for nismo 555 injectors?

Thanks

[skidder]

Anyone!?

[skidder]

observing the Alpha fuel learn during warm up (Open loop 02) the Alpha fuel learn's sit at 100% and 128%.

I am assuming that during closed loop light load my fuel trims sitting at 90% and 119% (average) the short term and long term fuel trims are removing fuel and singalling to go lean.

My high load mixtures however are pretty close to the estimated AFR. Can anyone confirm the injector latency for Nismo 555 injectors? I assume that the latency needs to be refined (reduced?) to resolve my light load and idle AFR richness?

Also to avoid creating another thread...can the source code be editted to limit the maximum TP that the 02 sensor runs in closed loop operation? I have been unable to resolve my holding closed onto closed loop issue at low engine RPM.

Furthermore I'm not convinced that my "TPS enrichment table" is working? I assume this is the TPS voltage required to ignore closed loop operation and in every case use the fuel values in the main fuel table?

Thanks for your help

[Matt]

Yes they are STFT and LTFT respectively

They work as percentages and 100% is spot on. It will adjust your global injection in conjunction with K constant

Use the wideband to command your AFRs however rather than use the estimated fuel AFR

Latency for 555CC injectors not sure (have you googled? Would need the measurement @ 14 volts)

There may be a parameter for closed loop TP adjustment but would need to look into it. As for TPS enrichment I've gone over the tables with the latest version. Still needs more work but please post in here:
viewtopic.php?f=12&t=2307&p=18350