Since changing from my stock 94170008 ROM to the "updated" 94170015 I´ve been having strange idle issues and a "stalling tendency" specially with the A/C ON. I´ve done the usual stuff (boost leak test, etc) to no avail, I decided it was probably normal. However, a couple a days ago we did the ROM change to another STOCK Evo 8 and it started with exactly the same symptoms. I decided to take a look at every table in the ROMS looking for differences and this came up:

The Iddle stepper look-up table is somehow linked to the "Desired ISCV" and "Desired Idle" tables, and this cannot be set to the stock 94170008 ROM Parameters.

You cannot modify the "Engine temp" values in them without modifying the "Throttle position" on the Look-Up table. This DOES NOT happen with the 94170008 ROM, as you can modify them without any effect over the look up table.

I´ve been unable to replicate the values seen on my stock ROM on these tables, and I believe this is the cause of my idle issues.


I´d REALLY like to keep my 94170015 ROM. Do you guys know any possible solutions? Thanks....

 

They look different because you have the wrong info. The X-axis is not based on TPS, it is a temperature scale. In 0008 the temp scale address is 6664 and in 0015 it is 68b8. If you have something different then someone has been playing with your scale mapping.

 

the address is right for 0015 rom it is just labeled wrong.

 

The address matches what you mentioned.

So the real issue is that on 0015:
Idle stepper lookup table, X-Axis Throttle position = 68B8
Desired ISCV, Y Axis Engine temp = 68B8

As you see, it references the same address.

And on 0008, it´s different:
Idle stepper lookup table, X-Axis Throttle position = 6664
Desired ISCV, Y Axis Engine temp = 6630



Could anyone give me the correct address values for 0015?
Thanks a lot.



-

 

It's supposed to reference the same address. Temperature scale is the same for a lot of tables, because it isn't really something that should ever be changed. It's just a scale.

 

After a major rom flash, you should always let the car warmup and leave it to sit and idle for 10 mins, then do the same again with the A/C on. The ecu "learns" an offset for your idle control system and should stabilise itself. If you still have problems, it is time to look elsewhere than the maps first.

Please re-read what I posted earlier. Your X-axis is not TPS, you just need to change the scaling type to Temp and use the addresses I gave you. Your Y-axis address was correct.

They will rarely be the same address. The scale address loacations are at the end of all of the map data, so for each rom there will be differences to the scale addresses depending on the number and size of maps. But, the displayed information should be the same.

Actually, just to confuse everyone, this table has sort-of always been displayed incorrectly by everyone anyway. It is Y that should have 8 elements, not X. There is a header at the top of the map data that gives this. But if you are confused with the addresses, dont try to change this over just yet.

 

<table name="Idle Stepper Look up Table" address="4399">
<table name="Coolant Temp" address="68b8" elements="8" />
<table name="Load" address="68d2" elements="27" />
</table>

That is the information in my 0015 rom, for some odd reason the Idle Stepper Look up talbe" does not come up in ECUflash, it is not there. Anyone have an idea?

Also, my 0008 ROM and my 0015 are both called TPS instead of coolant temp too, just like the OP.

 

The stock ROM (0008) doesn´t reference the same address, as posted.



Mattjin, thanks for your patience
I´ve changed the scale to temp on both roms, it should now be correct. However, the issue of not being able to replicate the stock (0008) values on the new rom (0015) is still there. Do you consider this a non-issue?


David, sorry, no idea why it´s not showing up.

 

Change the address in 0008 from 6664 to 6630 and it will. It all doesnt matter, because you shouldnt change values that are in your X or Y axis in most cases like i said (you can change them if you need more resolution for things like load or RPM). They are just scalings. What matters is the values inside the tables.

 

I think a lot of people are having issues because they change the scaling on their axis' but don't know how many tables use that same axis address. They edit the tables for the maps they can "see" but what about the ones not listed in ECUFlash? I try to NEVER alter my load scaling below 100 load becuase I know there are cruising tables for fuel,timing,etc that would get thrown off by this.

Because I do this I'm usually forced to have a larger gap somewhere in my map and I generally feel confident with a jump from 180 to 220 since my values are generally similar between that range and my powerband is above this area and when I am in the 180-220 load range...its VERY briefly.


Dave B, nice to see you chiming in, in this section lol. A rare occurance.

 

Add the following to evo7base.xml :

<table name="Idle Stepper Look-up Table" category="Idle" type="3D" level="2" scaling="ISCVSteps">
<table name="Engine Temp" type="X Axis" elements="8" scaling="Temp"/>
<table name="RPM" type="Y Axis" elements="27" scaling="RPM"/>
</table>


or:

<table name="Idle Stepper Look-up Table" category="Idle" type="3D" level="2" scaling="ISCVSteps">
<table name="Engine Temp" type="X Axis" elements="8" scaling="Temp"/>
<table name="Load" type="Y Axis" elements="27" scaling="Load"/>
</table>


I don't think anybody really knows what the Y axis scaling really is..

 

i changed my x-axis on the idle stepper table to 68b8 and the y-axis on the desired ISCV to 67bc.

 

Semi-OT

I had always thought about this. I'm a horrible newb when it comes to disassembly, but would it be easy enough to look through the disassembly and see if there are any routines that reference the load/RPM in the timing/fuel maps? That would be a great side-project if it was easy enough. For instance: it looks pretty clear that the timing trim and EGR duty maps reference their own set of load and RPM axes.

I know the rabbit hole is deep (as JB would say), but I was kind of under the impression that this had been thought out before.

 

mplspilot, THANK YOU VERY MUCH. I will try that this afternoon. I've actually moved that table around a bit to help the car start and idle better, so I wanted to carry it over to the 0015 ROM.

Thanks a bunch.

 

Could you explain why you did this, were you having idle issues? Or just to be able to keep the stock 0008 values in the 0015 rom? And why choose 67bc?