EFI tuning? What can you do with stock ECU

[Pube]

Anyone know what kind of chip/rom/eprom is used in the toyota ecu's?

[EldarO]

I can't speak for a Toyota, but I know for PGM-FI this isn't a good idea. It takes longer to re-tune itself from a re-set than it does just by changing the petrol.

ive done it before going from BP ultimate to shell 98, and the results were instant.

can idled smoother, was on boost quicker, and pulled a little better, but boost response was most profound change, as well as idle (semi solid engine mounts and no vibration through to me)

Elmo.

[oldcorollas]

I dont think thats right. My understanding has always been that when the ECU keeps advancing the timing until it picks up knocking on the knock sensor, then it retards the timing, but this is not permanent. If you put in a higher grade fuel, the knock will not occur until the timing has been advanced more, so the ECU will run this timing.

This means you will always run at max timing for the fuel you are using. It also explains why my car makes more power by simply putting in 98RON fue, without having ot reset the ECU

of course you are assuming that all ECU's have knock sensors

many do not. many do not have "learning capability", and instead just adjust within their set range.

learning, for AFR's will be limited to cruise conditions anyway, since the O2 feedback is meaningless (except on the few cars with wideband EGO sensors)

learning for timing will help, assuming engine has knock sensor, assuming it is sufficiently tuned or filtered to pick up knock correctly (ie, 4AGZE ), and that the ECU itself has the programming to actually change the base tables for ignition, as opposed to just adjusting within a given range....

[EldarO]

i was assuming "tuning" uncluded timing/knock.

my bad.

Elmo.

[Lachie]

I stand corrected. My knowledge about ECUs learning comes from when i was into nissans. Toyotas must be different. Appologies.

Umm, Nissans do the same thing! Ever put a timing light on an RB20 at idle - it goes nuts with the timing jumping about all over the place.

of course you are assuming that all ECU's have knock sensors

many do not. many do not have "learning capability", and instead just adjust within their set range.

learning, for AFR's will be limited to cruise conditions anyway, since the O2 feedback is meaningless (except on the few cars with wideband EGO sensors)

learning for timing will help, assuming engine has knock sensor, assuming it is sufficiently tuned or filtered to pick up knock correctly (ie, 4AGZE ), and that the ECU itself has the programming to actually change the base tables for ignition, as opposed to just adjusting within a given range....

True, and I totally agree, but the question was specifically about 4AGZE ECU's

[ra65]

ive done it before going from BP ultimate to shell 98, and the results were instant.

can idled smoother, was on boost quicker, and pulled a little better, but boost response was most profound change, as well as idle (semi solid engine mounts and no vibration through to me)

Elmo.

I wouldn't base that on an ecu. You notice that even on a carbie car. Good fuel makes car run better.

[Mr Revhead]

yes, if the car is lacking "good" fuel in the first place, of course running the correct fuel will mak an instant improvement.
however, depending on the ecu, running a higher octane can make a difference.