JECS ROM Download

[richh]

Ok, I tried the address and only 2 showed some data w/ one moving. Not sure what is it. You can tell me. Advance Multipier is 80224E

The engine load parameter on at least some of the 99/00 ECU's is one byte at 801308, so try that and see what you come up with. The one thing I'm unsure of is what, if any, conversion formula is done to the raw byte returns in order to produce the load value.

E**Tek shows load as g/sec of air. This value can be close to (but isn't the same as) the MAF voltage.

The MAF voltage and actual airflow value would never be "close" to each other, as MAF sensor voltage range is between around 1.0 and 5.0 volts, while airflow ranges are anything from a handful of grams per second to over 300, and the relationship between them is non-linear. However, if, as mentioned above, the ECU uses MAF sensor voltage as its primary load value, the scaling is less of an issue.

The ECU either appears to hold a scaling table, or a formula which converts vMAF into g/s. The scaling is distinctly non-linear - the difference in airflow between 1.1 and 1.2 volts vMAF is a fraction of that seen between, for example, 4.1 and 4.2 volts.

The SSM protocol apparently outputs the mass airflow in g/s as a 16 bit value at 0x013 and 0x014. I tried once to read this and cross-reference the MAF voltage value reported at 0x0H1D to deduce the lookup table, but can't get sensible numbers from the 16 bit reading. May be that I got the LS and MS bytes the wrong way round, or may also be that this function only works on the newer ECU's. I'll have another go with the byte order reversed and see what happens.

[west_minist]

My logging do not show load. I will have to try the addressed. But in dd, no
load.

Ok, I tried the address and only 2 showed some data w/ one moving. Not sure what is it. You can tell me. Advance Multipier is 80224E

Ok, I cross reference it and it seems to be a the Idle Control valve.

Just to let you know, I have a non turbo model.

It would be interesting to know if non turbo models in DD have load.

My friend own is MAP (non turbo) and no load is seen, except MAP psi variable

The Ecutek tool for 99+ until some date most probably change the maf to g/sec, maybe from variable from rom. But from that pic (http://195.112.37.59/products/deltaecu/), that is MAF voltage.

[x99percent]

The Ecutek tool for 99+ until some date most probably change the maf to g/sec, maybe from variable from rom. But from that pic (http://195.112.37.59/products/deltaecu/), that is MAF voltage.

So the MAF voltage only goes up to 2.75V ??

[x99percent]

E**Tek shows load as g/sec of air. This value can be close to (but isn't the same as) the MAF voltage.

The MAF voltage and actual airflow value would never be "close" to each other, as MAF sensor voltage range is between around 1.0 and 5.0 volts, while airflow ranges are anything from a handful of grams per second to over 300, and the relationship between them is non-linear. However, if, as mentioned above, the ECU uses MAF sensor voltage as its primary load value, the scaling is less of an issue.

The ECU either appears to hold a scaling table, or a formula which converts vMAF into g/s. The scaling is distinctly non-linear - the difference in airflow between 1.1 and 1.2 volts vMAF is a fraction of that seen between, for example, 4.1 and 4.2 volts.

Here is a screen capture from the E**Tek software...

I could be 100% wrong... but with as anal as they are, I don't think they would mislabel an axis.

[west_minist]

That's true.
I believe I need to understand how the load(grams) are calculated.

So we are looking @ mass air flow - g/s
Maf voltage - v
Load - g

[Freon]

Guys, that is correct. MAF voltage is converted to load, which might as well be unitless as far as the ECU is concerned. It just takes that load and looks it up whereever load is used as an axis on a map (mainly timing and fueling). It seems to be approximately exponential. There is a 2D Map that is 87x1 (or whatever, it is long!) with an 87x1 column header on the last WRX ROM I looked at.

FWIW, I think a lot can be done to tune intakes by adjusting that table. Once I get into it, I will be using the MAF to load table to flatten out fuel trims to adjust for my intake.

[x99percent]

FWIW, I think a lot can be done to tune intakes by adjusting that table. Once I get into it, I will be using the MAF to load table to flatten out fuel trims to adjust for my intake.

http://195.112.37.59/tuning/induction/

[STi6]

Here is another ROM to hack away at.

[richh]

I could be 100% wrong... but with as anal as they are, I don't think they would mislabel an axis.

Ah, no, you're correct, the axis isn't mislabeled, but we are talking about different units.

The MAF sensor, located where it is, and being the design it is, by definition measures the total amount of air being pulled into the engine. Hence grams per second being the quantity used by the SSM stream, MAF scaling table and so-forth.

The ECU map you quoted uses grams of air per cylinder per charge, so they're dividing the total g/s figure by engine speed and so-forth.

[west_minist]

Here is another ROM to hack away at.

Where you getting these roms from?

Help me get mine

[Hitokiri]

what I really want to see is a ae800 or ae802 - the standard WRX flash for europe

or a ae490 or ae491 which is the standard japan wrx

[Hitokiri]

that second dump seems to be the same as the first???

[STi6]

that second dump seems to be the same as the first???

Do you mean mine? First one was encrypted, this one isnt.

[STi6]

I've got an AE802 ecu for sale if anyone is interested. It got the stock map on it. Want $200 for it excl postage.

[west_minist]

Does this model have avcs?