Strange AFR Readings While Decel and During Shift

[NateCross]

This is a short log file from a base map I just finished up NOT tuned yet. Car runs and drives good, seems to be safe. No ignition retard, AFR is at least safe - although not always at my target which is OK for now until I tune it. Before I tune it, I was just doing some data logs to verify base settings and such, when I noticed some very strange AFR readings especially on in gear decel or shifting. In this log 43 to 45 seconds are a perfect example where the afr swings from .7 to 2.2. The engine certainly doesn't show any signs of this sort of violent change in AFR, and I don't really think that throwing 200% fuel at it for those points seems smart. Any advice on what needs to be done to smooth that out would be great.

Also, if someone wants to chime in on how I did getting a PRB base map set up for a K20A3 - it seems to be working well but I am not sure if there are any optimizations that could be made to improve it.

[NateCross]

Also - I noticed when using the PNF calibration I never ever recorded a single knock event and now with the PRB calibration it counts up to 100 or more by one city block. I do have poly engine mounts, not sure if that is the issue.

[Spunkster]

Its normal for the fuel injectors to shut off when decelerating and for it to show lean readings.

You need to determine if it is timing related that is causing the knock, or if it is something rattling that is causing it.

[NateCross]

Its normal for the fuel injectors to shut off when decelerating and for it to show lean readings.

You need to determine if it is timing related that is causing the knock, or if it is something rattling that is causing it.

Ok, so the very lean readings are normal. What about the extremely rich readings? Just want to make sure I don't try to tune out something that is normal operation.

Is there any difference between the PNF and PRB as far as knock strategy goes? I have imported every table and parameter from the old PNF calibration (which works great), so in my mind no real changes were made to the actual tune. Unless there is a setting or table I missed, which is possible

[Spunkster]

The values are interpreted differently from the fuel tables, so you cannot just import the tables from one to the other. It will need to be properly tuned.

[NateCross]

The values are interpreted differently from the fuel tables, so you cannot just import the tables from one to the other. It will need to be properly tuned.

Got it. That is what I was wondering. I figured there would be some differences, but wasn't sure what. Is it only the fuel tables that are different? Or all of them? Cause if I need to change things like knock sensitivity I wouldn't even know where to start with that. I know my fuel and ignition tables pretty well, but I'm not too sure about the others.

[Spunkster]

Anythign relating to fuel will be different.

[NateCross]

Anythign relating to fuel will be different.

Great, I can deal with fuel tables. I bet that is the source of the knock then. Once I get it dialed real good, is it possible to get this out to the community as an option for guys with a k20a3 who want to run a PRB calibration?

Also, would it be an acceptable starting point to use fuel tables from a k20a2 prb calibration for the a3 or will they be different?

I did port over the correct injector data, so that should be set right.

[Spunkster]

You can post your calibration here, or put it in the vault.

[Hectorabdiel21]

Hi, I'm new to tuning, I have a 03 rsx k20a3, full bolt-ons. PLM RH, HKS hi-flow full exhaust 2.5, TSX 310cc injectors, injen short ram intake, RBC IM etc...how did the calibration for the IM turn out?

[NateCross]

Hi, I'm new to tuning, I have a 03 rsx k20a3, full bolt-ons. PLM RH, HKS hi-flow full exhaust 2.5, TSX 310cc injectors, injen short ram intake, RBC IM etc...how did the calibration for the IM turn out?

Still working on it. Although this is simply a calibration for PNF based cars to use a PRB calibration. No intake manifolds involved.