Batch fire engines typically idle best in the mid 13’s, so if you’re leaner than that, put in some more fuel and see if that stabilizes the idle. You’ll need to make sure the air/fuel ratio is maintained during cold start. If your idle hunts when the engine is cold, but stabilizes when it warms up, try more warm up enrichment.
With a closed-loop system, the ECU checks the air-fuel ratio against the target numbers, but now the computer uses that information to adjust the fuel delivery to meet the target air-fuel ratio. The tuner also has the option of adjusting the correction factor and also switching between open- or closed-loop.
after 3 passes N/A on a new motor i had a best et of 12.7 .with a A/F of 12.9:1 at 28 deg timing .jetted 50 shot and dropped to 12.1 et with a A/F of 11.9:1 , leaned it out by dropping fuel pressure and ran 11.7 et with a A/F ratio of 13.0:1 when i pulled or added timing et dropped so 28 deg was the ticket for that jetting . hope it helps.
Cut the seal holding the black plastic lid in place. Gently pry the lid from the housing. To adjust, first mark the original location of the hold-down clamp on the gear wheel so you can return to stock setting if necessary. Loosen the clamp screw and rotate the gear wheel a few teeth as necessary. Clockwise leans the mixture, counter-clockwise
If you are tuning with a WB, it is to dial in your airflow tables. If your airflow tables are not dialed in, you can not simply calculate anything with any sort of accuracy. Basically my theory was that it would be possible to calculate your AFR based off airflow and calculated fuel flow.
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how to tune air fuel ratio
