91 Corvette need some help to make modest changes

**ddahlgren** · 09-12-2016

I downloaded TunerPro and found an $8D mask and a bin from what is claimed to be a 90 Corvette ANHT thinking it was close enough to get a feel for things and maybe ask some intelligent questions. I have no aspirations of modifying the engine other than get rid of some failing smog parts that I will save if needed later by me or a new owner. Tidying up the engine bay sure would be nice though. If the tuneup shows up as a real mess in some spots might tweak those but seems to run fine as is.

I want to change the following

Idle speed vs. engine temp ( found easily and ok there I think)
Air Fuel ratio for lambda 1 as E10 is a lot closer to 14.3 vs. 14.7 ( found easily and ok there I think)
Fan on and off temps ( found easily and ok there I think)

Switch settings that seem to baffle me..
Disable EGR errors as it is leaving
VATS disable at ECU and will jumper start relay so it cranks I will have a key cut with no pellet to verify done correctly

Any help on the switches section in general would be helpful as all the abbreviations seem cryptic to me.
The flyover hints are great for someone who knows what they mean but way to short for someone trying to figure them out.

Did look at some of the tables and have been programming after market EFI for decades Motec EFI tech and Haltech, it is what I do for a living for 25+ years.
Just work on race cars though so anything smog or street related is an alien concept for me.
What is the world is with 20 to 23 degrees of advance at WOT? I guess that might take me into data logging if I go in that direction later.

Any help would be greatly appreciated!

**dave w** · 09-13-2016

Attached are a few files that might help. TunerPro RT has a compare function, so compare the .bin I posted with the .bin you have.

dave w

**ddahlgren** · 09-13-2016

Thanks for sending the files I sort of get it by flipping back and forth between the 2 xdf files.
I guess my short question is what bits to turn off or on to eliminate VATS entirely and EGR entirely in the ECM.
The longer question is there some sort of cheat sheet for all the abbreviations in the switches section?
The constants are very clear as are the tables though suspect a learning curve as to how they relate to each other.
We manage to eliminate at least 50% of these tables and the car runs just fine but low speed operation is secondary as long as clean sharp and picks the throttle up well.

**dave w** · 09-13-2016

The .xdf I posted is a much improved version! Look in FLAGS to eliminate VATS (UNCHECK the flag). Look in SCALARS and set the EGR ENABLE MIN. MAT TEMP. to 151.25 c. I see no need or logical Tuning reason to eliminate any TABLES! TABLES are a TUNERS BEST FRIEND!

dave w

**ddahlgren** · 09-13-2016

I had no intention of removing them only the comment many more than I am used to seeing.

**ddahlgren** · 09-14-2016

I m slowly figuring this out while I wait for parts to get here.
I think I have the constants figured out and switches for error codes.
Playing with a file for a little learning I did find out in Win7 Pro the User does not have permission to write to the directory and has to be changed in the directory properties under security. So a heads up to anyone here.

I am getting a little pumped on the idea of data logging now after looking at some of the tune tables as some make little sense to me.
What is needed to log the 91 Vette ECM?

**ddahlgren** · 09-16-2016

OK here is my change list with the BIN and LOG file attached well with luck that I can get that done!
Goals
Fan on around 99C
Fan off at 90C
Lambda 14.3 to account for E10
Fuel cutoff / rev limit 5850
Fuel resume 5650
Add idle speed for hot engine to circulate a little more water
Lose EGR and EGR errors
Lose VATS and VATS error