Chasing my tail over trims and wandering AFCMD!

FlashPro questions & answers specific to the 2006-2009 (US, UK, Asia) S2000
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Shop Cat @ BCE
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Joined: Mon Nov 14, 2022 4:48 pm

Chasing my tail over trims and wandering AFCMD!

Post by Shop Cat @ BCE »

First post on the forum and trying to understand some logic as to what is going on with my calibration.
Setup is a 08 AP2 with a custom built turbo kit with ID1050x injectors, walbro 485 pump, ktuner flex content conditioner for flex fuel.
This is my personal car and daily driver so getting it perfect is always a nagging game...however I've run across something that I cant figure out despite checking the calibration and reading all of the available help.
Primary issue at hand is the fuel trims get wound down into the negatives which is problematic since the ecu applies that long term global trim to all the fueling including the wide open/boost fueling.
I've tried to track down and isolate it to as why the trims wind up as the car was tuned to stoic at all areas outside of WOT enrichment.
From what I've found so far the AFCMD target seems to be floating and the trims try to chase it but as it ends up being different than stoic it causes the trims to pull fuel even though the logged AF is correct.
For example: closed loop stoic target is set to 1, but while at idle and driving the ecu will flick the AFCMD anywhere from 1-0.92 while the engine is running and because the AF is significantly leaner than the value it randomly chooses it will wind up the trims to take fuel out (even though you would expect it to add...).
This causes a fairly large negative correction which takes absolutely forever to trim back as the ecu is quick to pull fuel but wont add it back in (even with short term trims winding up to their max values).

Very frustrating to say the least especially now that I am trying to sort out flex fuel.

Also it would be nice to be able to adjust injection timing on this ecu to optimize the larger injectors as well as a WOT lambda trim table for ethanol as they always run significantly richer wide open on ethanol which is really the wrong way to go with that fuel.
Any thoughts are appreciated!

Its also worth noting that my knock control value never changes from 55% so I have had to dull up the knock tables and tune the ignition tables to keep the timing in the engine as well as negate knock, again frustrating coming from the standalone world.
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Hondata
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Re: Chasing my tail over trims and wandering AFCMD!

Post by Hondata »

What are your injector dead times?
Hondata
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Re: Chasing my tail over trims and wandering AFCMD!

Post by Shop Cat @ BCE »

Hondata wrote: Mon Nov 14, 2022 8:49 pm What are your injector dead times?
Fuel system is a return system based around radium rail, direct mount fpr, and a new AP1 fuel hanger.
Base fuel pressure is set to 60psi as I was previously running this setup when the car was NA and on OEM injectors so I have set the injector information to info from ID for the 60psi base pressure.
fuel info.gif
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Hondata
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Re: Chasing my tail over trims and wandering AFCMD!

Post by Hondata »

Dead times look too low. General rule for ID1050 is 1.15-1.2 ms @ 14V.
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Re: Chasing my tail over trims and wandering AFCMD!

Post by Shop Cat @ BCE »

Hondata wrote: Tue Nov 15, 2022 11:57 am Dead times look too low. General rule for ID1050 is 1.15-1.2 ms @ 14V.
Ok, is there a 'known good' chart for ID1050xds injectors for use with the honda ecus then?
Also why does my AFCMD wander so much when target is LA 1 out of open loop?
This is the major issue with the car calibration as I'll tune it to stoic and then the ecu will change the AFCMD and cause the trims to wind up because AF actual doesnt match AFCMD.
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