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SAFC looses tuning after ECU reset?

Grim

By Grim,
in General Automotive Discussion

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Grim Proficient

Grim

Posted
Posted

I had my Apexi SAFC tuned to lean out the top end of the rev range but last weekend I had to disconnect the battery for ages and the ECU reset.

Now I've read that the ECU 're-learns' all it's settings so would it compensate for the SAFC and add more fuel to bring the mixtures back up to factory levels (ie. work against the SAFC and add more fuel)????

I only ask because now I get a lot of gurgling and backfiring when coming off WOT which I didn't get when the SAFC was tuned which makes me think it's running rich again... plus the car feels less powerful and a bit sluggish (I originally gained 25rwkw with the SAFC tune).

Should I bring the SAFC settings back to 0 then reset the ecu again and let it learn for a while then tune the safc back to it's leaner settings?

Or does an ECU reset not affect SAFC settings?

Cheers,

Craig.

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Guest INASNT

Guest INASNT

Posted
Posted

grim

i recon u should write down all the settings from the safc and then 0 them, reset the ecu, drive for a day or so and then re-enter the corrections into the safc!!

U cant go wrong that way.

But from memory when i didnt drive me car for 1 month and the battery died, the settings seemed to be the same with the new battery installed and drove the same. I have never noticed a change from reseting the ecu either.

doxximus Grand Master

doxximus

Posted
Posted

sounds good dudes

btw u know the digital dials display my KAP or KPA or KAR or whatever the hell it is next to the AIR gauge that shows boost isnt moving. is something else needed? like some kind of hose so it can sense it or what not?

the air works and everything else just not that

rev210 Grand Master

rev210

Posted
Posted

the ecu reset thing does nothing to the s-afc settings. Check them, they don't change.

The factory ecu has a crappy fuel map it follows, regardless of resets. I think your problem could be timing related. Here at least things can get out of whack. Also the plugs might need looking at.

JimX Grand Master

JimX

Posted
Posted
Originally posted by rev210

the ecu reset thing does nothing to the s-afc settings. Check them, they don't change.

That's not what he was asking, if you read his original message properly. He knows the settings haven't been lost, but he wants to know if the ECU is "re-learning" a wrong fuel mixture because of the S-AFC. I don't know enough about it to determine one way or the other, but my mechanic said an ECU reset won't affect it.

However, my fuel economy seems to have suffered recently after I got some speakers hooked up, which would have been the first time the ECU had been reset since my S-AFC was tuned. Could just be coincidence, I don't know. I'd really like a definitive answer on this. Wish I could afford a PFC :P

predator Grand Master

predator

Posted
Posted

Mine totally went out of sync once running very badly like you describe, and i am not sure the exact reasons..

I did reset the ECU inbetween, however whether this killed my S-AFC adjustments i don't know. I didn't notice any difference whatsoever in the ECU reset.

You would think however if you reset the ECU it would go back into learning mode and learn back from the adjusted S-AFC settings, not the standard sensors -> if anything a good thing.

A plug change and retune (timing, S-AFC, etc) in mine fixed everything up however and it has been running fine for a couple of months now.

JimX Grand Master

JimX

Posted
Posted

The S-AFC uses static ram to save its settings, so even by cutting the power for years it shouldn't erase your settings. There is a reset button on the unit that does that.

In theory the ECU learns off the exact same AFM signal whether standard or modified by AFC, the only variation in the fuel injector output comes from the ECU itself. The ECU reset shouldn't care whether or not it has to re-learn everything from a standard or modified signal, it should end up exactly where it was before the reset whether the AFC was in use or not. If it "knew" about the AFC, then it would gradually end up compensating for all the AFC settings and you'd have to reset the ECU every few weeks.

That's all in theory of course, because it still doesn't explain why my economy has suffered. Maybe I just need to give it more time to learn an optimal mixture. It's been 3 tankfuls so far and it's in the low 14'sL/100km, whereas before it was as low as mid 13's.

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