RomRaider

Has anyone discovered in the 32-bit ROMs any control logic for alternator output.

I have confirmed on my car, as well as another identical, the behavior that battery voltage (logged) varies considerably from 12.4V to 14V. Now if I turn on the lights, then output is back up to 14V. Others have experienced this too:-

http://www.subaruforester.org/vbulletin/f85/design-fault-smart-voltage-regulator-38052/



I guess Subaru trying to keep things efficient as possible.

is idle speed target rpm changing when you enable high electrical load?

I know in the 16b roms there are two distinct idle targets depending on whether that register is toggled

I haven't checked but will do. Seems to idle the same.

Now the reason I bring this up is because I was occasionally running lean under full throttle. Today I logged battery voltage and it seems that when the voltage is low, despite going full throttle, it stays low Thus not providing enough power to the fuel pump etc.. If I turn on the internal fan, voltage stays at 14V and no more lean out.

So for whatever reason the load sensing is not related or triggered by engine load. This is really disapointing. Could be that for a stock setup it works to specification.

same issue here.

Full hardwire, so MAF scaled at 13.8V, but when ECU drops to 12v I run 0.5AFR leaner. There is a standard SSM parameter called alternator duty, it will be 0 when altenrator engaged (13.8v), 100% when alternator disengaged. WRXs don't have this wire connected, so they 13.8V+ all the time.

Non-elegant solution - unpick the blue wire from alternator plug.

Elegant solution - un-pick the ECU logic. I'm looking at all the refs to alternator duty in the ROM, I've found a couple that sort of make sense, but still looking. Hopefully td-d can weigh in his definition god powers.

i would also consider tuning injector latency vs voltage values an elegant solution.

Looks like I found a way to switch this mode off, aijii's test so far proving positive. I agree latencies would help if you were dealing with just idle and light cruise areas - but the leaning being experienced is in high load areas, with high IPWs - where latency is a minor part of the fueling equation, relatively speaking. Certainly not enough to causes 0.5 AFRs difference.

I'm also testing this - similar situation, hardwired pump, was also getting very odd results - one drive perfect fueling, another very lean - seems it was the same issue. Driving with lights on, or defogger (or other significant current draw) results in predictable fueling.

very interesting!

ken

I can confirm, this works 100% - my voltage now stays between 13.8v and 14.2v, and my fueling has stabilised markedly - even with significant IAT differences. For big builds with hardwired fuel pumps, and those ecu that have the 'smart' alternator functionality - probably advisable.

is that the correct address AZ1G202G = "13C7C"

Yup, that's the address.

Is there any hint or clue how to easily find the right address?

Can you help me with the address for AZ1J500G please

bumping this

also curious how to disable this annoying function
EDM FXT MY07

Anyone know what to change the value to? I took a look in Ghidra for AZ1G202G described above, address 13C7C defaults at 100.0.