I was browsing through the Evo 10 FSM this morning trying to better understand the fuel injection system and came across a very nice block diagram explaining what sensors are involved in creating the fuel pulse width. Prior to seeing this, I was beginning to strongly believe that the Evo 10 was controlled only MAP/MAT and that the MAF sensor was purely for diagnostics (OBD-II). However, based on this block diagram (from GR00004700-13A) and other things I have seen, the fuel control on the Evo 10 is by a combination of MAF and MAP. According to the block diagram below, the basic fuel pulse width is calculated from the MAF signal, and then compensations are performed based on things like MAP and MAT. The compensation from MAP/MAT can be quite significant as the Z-chip alters the MAP signal to indirectly modify AFR, timing, MIVEC, and anything else compensated by the MAP signal.

This means that there is a bit of a hole in the ECUFlash tuning capability because as of yet, no one has found a verified MAF scaling table, or anything else related to MAF.

There's also lots of other interesting info in this tech document that I am reading. In particular, it discusses all the sensors that are used. I think its been mentioned before, but the Evo 10 MAF is a hot wire MAF rather than a KV MAF used on prior Evos. This means that the MAF signal is now an analog 0-5V signal, so anyone looking for the MAF signal in a disassem should be looking at the ADC input reads.

 

i tune these cars with the Maf scaling just like a subaru :-p

 

This might help?

<scaling name="MAFVoltScaling" units="units" toexpr="x*5/1024" frexpr="x*1024/5" format="%.3f" min="0" max="255" inc="1" storagetype="uint16" endian="big"/>


<table name="MAF Comp Test 1" category="Intake" address="5753a" type="2D" level="1" scaling="uint16">
<table name="Volts" address="615ea" type="X Axis" elements="69" scaling="MAFVoltScaling"/>
</table>

<table name="MAF Comp Test 2" category="Intake" address="575c4" type="2D" level="1" scaling="uint16">
<table name="Volts" address="61674" type="X Axis" elements="61" scaling="MAFVoltScaling/>
</table>

 

Very interesting. I have heard that with Subaru's MAF scaling is very important (i am not positive though) but would it then be safe to assume that the Evo X is the same way? Meaning that a decent amount of power could be picked up by scaling the MAF properly? Or does it not matter if the MAF is scaled wrong as long as your afr, timing (no knock detected) etc are good?

Just curious that if we do get MAF scaling in ECUflash if its worth retuning for or not?

 

Yeah, I've found the first table. Your defs are off a bit. There's 130 elements in that first table. The scaling is off a bit too. It should be 5/1023 and 1023/5. I'll look at the second table later today.

 

Yea somebody else posted that a couple months ago, so it could be (is) off.

 

Good find, thanks for info!

 

The second table is a continuation of the first table. Whoever posted the tables probably did it like that so that all of the table elements can be seen in ECUFlash.

For the Evo 7/8/9, MAF rescaling was only required to compensate for aftermarket intakes that altered the airflow pattern through the MAF. Hard for me to say what value there is for the Evo 10 because at this point, its still not obvious to me how the Evo 10 uses the MAF signal because I have yet to track down the MAF signal RAM variable. And I don't know of any tuners with other tuning software (ECUTek, Cobb?) who have tried messing with whatever MAF tables they have at their disposal.

 

Mychailo .. I have 4 of the 6 tables listed.. I think you do too .. Also IAT compensation (maybe) as I haven't delved into that yet .. IAT 2 is post IC temp for computation of MAP temperature as compensation.. 0x808756 (or 7A can't remember)

I do not know what they do thats why I still have them as unknown ..

I am so busy with FIXING bad roms from tuners that I barely have time to do much disassembly now ..

I think I should start charging $$$

The MAF is now used more as a check and balance to control the amount of 'power' the engine makes .. MAF output is referenced at most (I think) of the power restriction tables .. my current limiting factor is I can't log .. so I can't verify ..

OH BTW .. if anyone is wondering why all these controls .. they are to protect the SST gearboxes .. not much else ..
I have tweaked some control tables to the extent that you'd think the SST gearbox has broke .. so if the MR guys are complaining trans slippage .. its time to take a look at the limiters

 

Yeah, I've tracked down the two IAT scaling tables if that's what you mean. Interesting that you think the MAF is only used for diagnostics and limiting power. That was my theory as well until I saw the block diagram in the factory service manual. More digging is needed to find the truth. :-)

 

1) There is a strong strong possibility I will be the proud new owner of an X within a few hours - so I will be able to much more active in X development - you guys have done a fantastic job to date

2) EvoM mods have previously warned about posting images from the FSM - I am not sure of the exact problem with this (copyright I am guessing) but something to think about

 

while all the tunners are in attention here....

are you guys having problems to read the 2009 evox ecu?
i just cant connect using ecuflash...

 

No 2009's in USA.

 

No issues with the JDM 2009, which one are you working on?

You can leave that up to me so you have more time to work the tables

 

im working on a 2009 USDM GSR Evo X

(remember guys politics appart PR is a US territory and abides to US commerce whats on sale here comes from US ports and the Mitsubishi stock gets supplied by MMNA we don't have the luxury to call Japan and ask for an Evo, not even dealers have that power, dealers ask Mitsubishi Motors Sales of Caribbean and they in part make the order via MMNA)


i dont know about the continental states but to PR we have '09 X's.. the main differences are colors available (we have Rotor-Glow X's and Ralliarts) and taillights (wich are black)
USDM not EDM nor JDM......