Running extremely lean when started 1:18 - 1:20

K-Series Programmable ECU Calibration updates / downloads
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Location: Belgium

Running extremely lean when started 1:18 - 1:20

Post by A4XRBJ1 »


finally got it and connected my PLX device wideband sensor to the Hondata through ELD. Changed it in the software under settings, wideband input to PLX M Series on the quick select.

Numbers are displayed correctedly, in accordance to what the PLXdevice display says.

Now comes the problem. After 90 seconds of cold start it idles around 1:15, but from there it goes into getting leaner and leaner. At 2:20 min. the first correction on the short trim is done from the ECU (I'm already running 1:20 then). When I rev it all seems to go well, quickly going into 1:11.85 at the lowest. When I get off the accel. it goes back to 1:20.

I then changed the idle rpm at 5:28 min. to 900 (from previous 1000 rpm) and the car seems to idle a little bit better, but not for long at 5:36 it goes back into the 1:20 AFR.

On the other side I see the gasoline being thrown out of the exhaust when I rev it, what can I do to get the idle to stochiometric?

Does the ECU needs to run a long time in idle, to correct itself on LTFTs?

No tuning is being done so far, running on the base cal file for AP1, just the map sensor and other parameters specific for my setup are changed, not the ignition or fuel tables.

Like I said in another post, tuner postponed the tune to Friday 24th. Can I still drive with the car until then?

Calibration and datalog is attached.


s2000-ap1 AW with Wideband.kal
My current calibration file based on stock AP1 cal from Hondata
(46.75 KiB) Downloaded 271 times
Cold start2.kdl
Cold start with AFR's running into 1:20 after some minutes
(524.49 KiB) Downloaded 176 times
European Honda AP1
Vortech sc w 14 PSI boost w aftercooler
Hondata KManager Ver.
RC 750cc
AEM 3.5bar MAP
ERL/Aquamist water injection system 2D
Head & manifold ported by Alaniz
3'' custom built exhaust w Berk kat

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Location: Hondata

Post by Spunkster »

You have 750cc injectors, you cannot expect it to just start and idle prefectly without tuning. You will need to make adjustments to the fuel trim until you get it to idle near where you want, then start making changes to the fuel tables to fine tune it.

If you cannot tune this yourself I would suggest putting the stock injectors back in and load a base calibration back in to the ecu and just drive very carefully until you can get it tuned properly with the larger injectors.