re-mapping and live tuning L28ET 1982/83 S130 ECCS

[stupid_fast 3]

I made a mistake by saying 'air flow would be consistent'.  

I'm trying to figure out the explanation as to why there's a severe drop in AFR after a certain RPM, but the fueling would remain constant with a flat AFR target above that value. 

[Gollum 28]

Likely because you DON'T have a "VE" table anywhere. You have an "AFR" map as your only "fuel" map (that you've posted or shown me). There's an ignition map, but that's unrelated. So once the AFM is maxed out, the ECU likely takes that reading as it's "max flow" reading and the AFR table adds fuel on top at higher RPM where necessary. This means that in WOT beyond max AFM flow you're only operating on RPM scale, like an alpha-n would at WOT.

Edited April 4, 2019 by Gollum

[bradyzq 13]

Yup. Your main fueling is calculated from the AFM voltage and RPM. No VE. Though there may be an as yet undiscovered WOT fuel map that is unrelated to or a further multiplier of AFM fueling.

 

@Gollum, sorry. I thought the MS logs stupid_fast was referring to were yours.

 

Also, if one is trying to figure out how this stock file works on a modified engine, you may get some weird things going on, such as going off the end of tables. You can see that a stock boost 280ZX likely would have followed a slightly leaner AFR trace, and maybe not hit the last TP column.

[stupid_fast 3]

I was referring to Gollum's megasquirt logs.


I've just updated the rom data translation spreadsheet with my more recent findings. 
https://github.com/eccs-reengineering/280ZX-Turbo-ECCS/blob/master/Rom Data Translation/S130T_ROM_Address_Translation.xlsx

You're welcome to look, and if you have any questions about a specific table I can test the results of changing it.  I've modified and tested almost every bit of used data while the engine is running to find out what it does.
I've verified which maps are in fact used, and which are not by checking which tables are referenced and loaded by the assembly code. 
 

The next step is to verify if in fact the AFM is hitting its limit. 
If so, the real solution would be finding a way for the ECU to measure flow past the AFMs max flow capability. 

 

 

Edit, found what appears to be the injector constant (Generally referred to as the K constant in the Nissan world) it is a DWORD at 1F44 on the stock rom.
Adjusting this dword changes fueling characteristics across the whole range. 
 

Edited April 6, 2019 by stupid_fast