TBI headache

[robertisaar]

which dumbass at GM decided this:

when in ALDL mode using a 10K resistor, it ADDS TIMING?!? how the hell are you supposed to get the main advance right when its gonna knock like fucking crazy?

[Superdave]

that doesn't make sense...

[robertisaar]

according to some sources, alldata included, when a C3 ECM is put into ALDL mode by using a 10K resistor at the terminals, it adds timing, and i've heard anywhere from 4-10*... it also raises your idle to 1000 RPM and a few other things as well.

[robertisaar]

OK i haz an update:

in $4E code, at location $1F is a value for spark added in ALDL mode.... 8 degrees in AZNU...
in $42 its at $23, in ABHC its 8 degrees.

SO: for anyone tuning a C3 ECM:

BE AWARE!

[Canyonero]

What ECU is this? I've been running my '7747 almost all day with the 10k on.

[robertisaar]

4E is a 1228062, 42 would be a 1227747.

check that value out and see what it is.

i zeroed it out and ALL knocking issues have since disappeared as well as a code 42 or 43 can't rememeber.

[Canyonero]

My truck came with an '8062 running the 2.8L, but I couldn't find an xdf to work with it. I swapped over to a '7747 with a 5-speed $42 bin which is what I was tuning on yesterday. I have the moates APU1 which has a switch for the 10k resistor, and WinALDL was showing the 10k Diagnostic Mode flag on.

[robertisaar]

the 8062 does indeed have a XDF, check the TP website. i was probably the one that sent it to mark for him to post it there anyways...

seriously, check those values. or even look at any of the hacks that go through the algorithm, you'll see it.

why GM decided to add spark in 10K mode, i have NO idea... it also changes the idle RPM on a 8062 to 1000RPM. i believe i have also found the location for that as well.

[Canyonero]

Oh, there is a 4E.xdf on the tunerpro site, but everything shows as zero when I open the bin I pulled off the stock chip. Is there some trick I'm not doing? I can burn the bin off the stock 2732 chip to a 27SF512 and the truck runs just fine with it.

[robertisaar]

i'm thinking its an offset issue... feel free to send me the BIN(@yahoo.com)(or post it here) and i'll see what i can do with it.

or even just post the BCC. i probably have it on my laptop.

[Canyonero]

Ok, attached it.

[robertisaar]

i don't even have to download it... its 32KB, while its supposed to be 4...

EDIT: here's a fixed version. opens fine in my XDF.

[Canyonero]

How did you fix it? Should have have done an offset when I read the chip?

[robertisaar]

shouldn't have needed to actually, since it was a 2732 chip, right? they can only hold 4K, i'm not sure how yours was bloated to 32...

i pulled the BIN off of my 85 TPI IROC(2732) and it was only 4k... not sure why you would need to offset anything unless it was a different chip.

[Canyonero]

Now that's interesting. The BPC is 166, which is exactly what I calculated for the 3.1L w/ 36# injectors (used in the 91-92 Isuzu Rodeos and pickups). The 2.8L with 36# (89-91 Troopers) should have a BPC of 150. My 3.4 with the 46# figures out to be 143.