This topic on reading MAT has gotten a bit convoluted, thanks to myself. First let me clarify on temperature variables available on the stock MUT setup:

MUT11 is IAT after its been through the scaling table in the ECU. The scaling needed in a logging program to read IAT over this MUT channel is x-40 for deg C and 1.8*x-40 for deg F.

MUT3A is the raw IAT ADC signal straight from the sensor with no scaling whatsoever. The formula in EvoScan of 1.8*x+32 is a custom thing that Hamish did before I found that scaled IAT was available on MUT11. Hamish inserted his own custom scaling table in the EvoScan code (not accessible by end users) to convert the ADC signal into a scaled value. It meant only to work with a Mitsubishi IAT sensor, and will not work with the GM IAT. Bottom line is that there is no need to ever use this MUT channel because real temperature is available on MUT11.

Now onto SD. Here is the info for USDM ROMs:

What I said before was partly correct. Here is the correct part:

Option A - If MAT is being read over the IAT ADC, then my MAT compatibility patch is not needed, and the MAT sensor scaling gets dumped into the IAT sensor scaling table.

Option B - If MAT is being read over the fuel tank temp ADC, then my MAT compatibility patch needs to be applied to the SD ROM.

What is incorrect is that I said my SD ROMs were setup to read MAT via the IAT ADC. The patched ROM is actually setup to read MAT over the fuel tank temp ADC but does not have the MAT compatibility patch applied. In this configuration, if the MAT sensor is wired into the fuel tank temp ADC input, then SD will work properly, but there's a good chance some sort of evap CEL will occur (that would not affect engine performance). However, if the MAT sensor hooked up to the IAT ADC input with no changes to the SD ROM, then the MAT values would be inaccurate. In retrospect, this was a very confusing way to set it up. I'll have to rewrite that first post tonight or on Monday evening (probably Monday evening because I'll have my server back online and can post updated patches as well).

Now specifically for the 9653 ROM:

My base 9653 SD ROM is also setup for reading MAT over the "fuel tank temperature" ADC input. I use quotes because there is no fuel tank temperature sensor code in the 9653 ROM, and to keep things short, no MAT compatibility patch is required when using this input for MAT on the 9653 SD ROM. It will "just work" in the same way that boost sensors "just work" for this ROM.

 

Yes, I was confused about that as well and questioned several times and I thougth that I had different answers.

I always thougth that if you wanted to run SD with MAT wired into the fuel tank ADC that you needed the MAT patch. But then, I remember you telling me that for 96530006, the SD ROM was setup to read from fuel temp ADC from the IAT scaling table and the MAT patch wasn't needed.

So, the consensus and correct answer is that the MAT patch is needed when running the MAT into the fuel temp ADC when running the SD ROMs. I think that's what you are saying above. I will wait for your updated posts.

 

Oops. I forgot about the 9653. Its different than the USDM ROMs. I've edited my previous post to cover it.

 

So, if I'm reading this correctly, you're saying that for SD patched roms except 9653xxxx roms (including the pre-patched ones you and phenom posted?) then your MAT patch is required.

If you are using 9653xxxxx (which I think a lot of us are that are currently active in this thread) we do NOT need the MAT patch at all, and of the MAT scaling is done in the scaling for the original IAT table? If this is true, and the MAT patch is applied, does it break anything? Please see my post above, #259, re: which MUT to log for proper MAT readings and the differences in values? I had logged MUT09 and MUT3A...

I swear adding the MAT patch to my 96531706 rom and fixing the scaling (C vs F) in the tables made a difference in driveability...the car seemed to go lean on throttle tip-in (as though VE tables were not correct) but after the above it seemed to go away. Gah, sorry I'm still confused!

 

Ok, so if I'm currently set up to read through the IAT temp input, then the scalings that are listed there are not correct...correct? And in which case, I never should've added in the extra code to the xml to allow me to use the maf plug as the input?

So if all that is true, how do I import the MAT scaling over to the IAT since currently my MAT table lists 1 constant number for the entire table and looks thoroughly screwed up? Or do I not have to bother? Man I'm still just as confused lol...if copying the scaling into the IAT table will work I'll do that instead for now and later on swap over to the MAT input.

 

If you want to leave the MAF hooked up and use the Mitsu IAT sensor in the MAF for fuel calculation, you need to rescale the table for the Mitsu sensor:
Set the "Input for IAT" option to 0x03
Open up a stock 96530006 ROM
Change ECU ID to 96531706
Close the rom and reopen so it opens using the 96531706 xml
Copy the values from the IAT scaling table from the speed density programming section into the same table on your speed density ROM

If you want to hook a GM IAT sensor into the MAF plug for fuel calculation:
Set the "Input for IAT" option to 0x03

That's all that needs to be done as the stock IAT table has already been rescaled for the GM IAT.

Here are the two tables.
Stock IAT scaling on the left, GM IAT (default map in 96531706) on the right.

 

Are we getting confused because some of us downlaoded the tephra v7 96531706 rom from phenom's post, option 5, and some are patching the stock rom (or base tephra v7) and then possibly changing the romid to 96531706 per prev post?

 

Could be the issue.

If you downloaded Phenem's pre-patched rom, it has the correct IAT table rescaled for the GM IAT sensor.

If you started from a stock ROM, then you'll need to change that table to the appropriate table for your IAT.

Speaking of IAT sensors though, I wish I had seen this sensor before getting the standard 3/8" NPT plug GM IAT.

http://www.t1racedevelopment.com/en/...at-sensor.html

 

..but uses the fuel temp sensor input as the source. And what is the correct MUT to log for actual MAT?

This totally makes sense for me now; I was logging MUT09 before and wondering why my values were all goofed up, but then when applying mrfred's patch I saw more realistic values. If the MAT patch is not needed for this rom and MAT can simply be logged elsewhere (and/or MUT09 updated/copied to mimic this value?) it would make implementation of SD on an evo8 a lot easier

 

MUT09 is specific to MRfred's MAT patch, which does not need to be used on the 9653XXXX speed density patch. I think the real confusion just came from the 9653XXXX specifics. It doesn't have the original fuel temp routine that needs to be bypassed in all the other ROMs.

The patch kept getting brought up though because the other SD patched ROMs need the patch applied.


MUT11 is what you want to log if you are using 96531706.

 

Okee, I'll try ripping out the MAT-logging patch and also log MUT11 and see what happens. cold/warmup driveability is my only issue now, and only since it has gotten colder (~0°F). Never was an issue before though, which is what kinda troubles me. Cold idle is dandy

 

Wow...that table you posted compared to mine is way different. I'm hoping it's just the scaling that's set differently, but mine is like this...



Completely different than what you have. I also think this is the 3rd release of that rom, so it probably isn't the most up to date.

 

My temp scaling is in Celsius

Yours looks to be in Fahrenheit, hard to read though so I'm not positive.

It's not a complete table, I just posted it up to show the difference between a stock table and the GM IAT scaled table.

 

This is true only for USDM ROMs and only if the fuel tank temperature ADC is used.

The MAT patch is not needed for SD. However it is needed to log MAT in absence of SD. Applying the MAT patch would not affect the SD performance. However, its important to remember that the SD option for temperature sensor input needs to be set appropriately. If the MAT sensor is attached to the IAT ADC input, then the SD option for temperature sensor input needs to be set to 0x03. If the fuel tank temperature ADC is used, then it needs to be set to 0x0E.

If you want to be absolutely sure that you did not inadvertently mess something up, start with a fresh 9653 SD ROM. I've got one that you can use if you want.

 

Just finished looking at the MAT scalings in the SD variants of the tephra 9653 ROM. As I expected, both ROMs have the correct scaling.