Need some $5b XDF /VATS help- 3800 SC 16183247 ECM

[darbysan]

I found what may be a discrepancy in the XDF I'm using, but I need someone with more smarts than me to confirm. I took one semester of Assembly Language, and that was 45 years go!

Trying to program my 16183247 ECM from 95 Riviera, 3800 SC engine. I used XDF $5b 94-95 L27 L67 3.8.xdf file , 5B7a.adx. I was able to download the stock bin BKZS from the donor vehicle. Engine is installed in an '87 Fiero.

The problem is that I'm having issues getting VATS to disable. I "unchecked" the VATS enable box, saved the file, burned the chip, but car acts like it has Vats enabled. Engine runs for less than a second and dies. I cleared all codes, and Using TunerPro RT, I can see the Error Flag on VATS change as soon as I turn the key to try and start.

In the above referenced XDF file, the VATS Select flag shows Flag, Offset 8013, Mask:1 Using the HEX editor, I can see that the value changes from FE to FF, when I go from Checked to Unchecked. I used a different XDF file, $5b6, and find the VATs Select flag at 800E, Mask:1 , and the values switch from 00 to 01. All of this may be irrelevant, but I wanted to give as much info as I could.

My Question #1 is "Could the VATS location in the first referenced XDF be wrong?" That XDF has many more variables defined, and looks like it would be the better choice to use.

I've been advised that the Error codes will still set in the ECM, , even though VATS has been un-selected, and that I would have to disable those codes separately (626 and 629). The suggestion was that the Injectors may be stuck closed from sitting, and may need to be cleaned, rather than a VATS issue. Is this a fact- that the error codes will still set, even though VATS is not selected?

Only place I could find in TunerPro to change the error codes, other than de-selecting the Flags, would be to delete them in the ADX file. My thinking is that will just change what I see when data logging- not what gets set in the PCM. Can you give any advise on how to Disable these codes as well.

As always, appreciate your help.

[steveo]

My Question #1 is "Could the VATS location in the first referenced XDF be wrong?" That XDF has many more variables defined, and looks like it would be the better choice to use.

potentially, yeah.

5B and 5B6 are different. are you sure about your mask? does everything else look 'sane'?


Only place I could find in TunerPro to change the error codes, other than de-selecting the Flags, would be to delete them in the ADX file. My thinking is that will just change what I see when data logging- not what gets set in the PCM. Can you give any advise on how to Disable these codes as well.

correct. the adx is just an interpreter for what the ECM sends out for data.

de-selecting the flags is usually the correct way to disable an error code, although sometimes you can disable the device in question. might have to be more specific


In the above referenced XDF file, the VATS Select flag shows Flag, Offset 8013, Mask:1 Using the HEX editor, I can see that the value changes from FE to FF, when I go from Checked to Unchecked. I used a different XDF file, $5b6, and find the VATs Select flag at 800E, Mask:1 , and the values switch from 00 to 01. All of this may be irrelevant, but I wanted to give as much info as I could.

to look at this in terms of binary flags (which this is) think back to your punchcard days.

FF=11111111
FE=11111110
00=00000000
01=00000001

everything but that last digit is another probably unrelated flag

is there a disassembly of this mask?

[darbysan]

I just found the problem!! There was another thread regarding an earlier year's ECM, but same general issue, that I hadn't found before because I was searching by my ECM number. http://www.gearhead-efi.com/Fuel-Injection/showthread.php?2017-VATS-issue-3800-L27-to-L67-5B4-5B5

In that post RobertISaar gave come insight into the Factory Setting of that bit 8013 as FF, but the program is looking for 0 / non 0 to disable VATS. ( In the referenced thread, is was bit 8014, not 8013). I edited the 8013 bit to 00, and then for grins re-checked the VATS box, and it changed to 01 ( sort of as expected). So I unchecked the box, and it re-set to 00. Burned a new chip, installed, and it fired up on the first try!!!!!!

So just to make it easy for someone else searching this thread, uncheck the Vats Select box in Flags, and then use the Hex Editor in TunerPro (Tools, Advanced) to change bit 8013 from FF to 00. Commit the change, and then save the BIN.

[dave w]

Thanks for sharing your experience!:thumbsup: I'm sure someone will find your information very helpful.

dave w

[steveo]

8013 is a byte. bit 1 is a bit. there are 8 bits in a byte. ff is all on. That's eight flags. 00 is all off. its rare that a byte only contains one relavent bit. im glad you solved your problem but you probably disabled more than just vats. just throwing that out there.

[1project2many]

I was intrigued by the potential deselection of multiple options as well. Referencing the thread linked above, it appears VATS choice include a byte value of 00 or FF rather than the typical bit value of 0 or 1.

[RobertISaar]

a lot of the later OBD1 code has those types of option "masks".... why GM chose 0/non-0 operation instead of just setting up a bit, I don't know, the amount of code to interact with a bit vs a byte is pretty similar.