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Potential bug: discrepancies in the recently exposed fuel tables

Posted: Fri Aug 01, 2025 12:37 pm
by jeffx
A few releases ago we got some new fuel tables, labled Fuel Pressure (Mode) and Fuel Pressure (Blend).

I have noticed that the values in the Fuel Pressure (Blend) tables for the baseline calibrations differ between the 2017/18 FK8s and the 2019-2021 FK8s. However, the 2019-2021 FK8 Fuel Pressure (Blend) tables match the ones for the FL5/DE5 Fuel Pressure (Blend) tables and the Fuel Pressure (Mode) tables match the Fuel Pressure (Blend) tables in both of these platforms as well. So are the tables in the 2017-18 FK8 calibrations the "correct" ones and the 2019-21 and FL5/DE5 tables wrong, or is it the other way around?

as you can see in the attached graphic, the Fuel Pressure (Mode) tables are the same across all 3 platforms
Fuel Tables.png

Re: Potential bug: discrepancies in the recently exposed fuel tables

Posted: Fri Aug 01, 2025 12:40 pm
by FK8_Hoonigan
Also, due note the RPM index on the 17-18 as shown above, differ and indicate 1800 rpm instead of 2000rpm

Re: Potential bug: discrepancies in the recently exposed fuel tables

Posted: Mon Aug 04, 2025 9:04 am
by Hondata
Nope, double checked FK8/FL5/DE5 and the tables are correct. So the 17-19 FK8 has an odd blend table from the factory.

Re: Potential bug: discrepancies in the recently exposed fuel tables

Posted: Mon Aug 04, 2025 9:12 am
by jeffx
Interesting. thanks for clarifying.

Re: Potential bug: discrepancies in the recently exposed fuel tables

Posted: Mon Aug 04, 2025 9:40 am
by jeffx
while we're on the topic, can you help us understand what the Blend and Mode tables are meant to do?

It seems like at cold start, if you let the car warm up without moving, the ECU follows the blend table until it reaches some point where it seemingly switches to following the idle fuel pressure table. I checked it a couple times and it seems to occur after around 30s but the ambient conditions haven't changed enough between my cold start testing to rule out the possibility that it's temperature related.

Are there any other times that the Blend table comes into play?

How about the Mode table, what is the purpose of the Mode table?

thanks

Re: Potential bug: discrepancies in the recently exposed fuel tables

Posted: Mon Aug 04, 2025 9:46 am
by FK8_Hoonigan
I can confirm.
I have datalogs from multiple cars (FK8/FL5) showing upon COLD START ( ECT = IAT), the Fuel Pressure (blend) is the one being used in the first 30-60s