Diacom, Spark Advance, 1985

B84RADR · 02-10-2004, 04:28 PM

Gentlemen,

I asked this a while ago but wasn't able to come to a conclusion.

The 1985 ECM does not display Spark Advance data in Diacom. Someone, somewhere, figured out a way to hack some of the hex in a .bin and display that data in the Prom ID field. Doing multiple searches on the internet hasn't yielded very many results. I'm just hoping that by posting up here it jogs someone's memory on where I can read up on this to make it happen.

Any takers?

GRX · 02-16-2004, 04:02 PM

I'm hoping too that someone has an answer :lurk:

B84RADR · 02-17-2004, 01:00 AM

I have looked everywhere. Still looking. TunerCat said they would check a few more of their resources if I came up completely empty handed. I've posted messages on four different boards, but no responses. If I figure it out, I'll definitely add it as a tech-tip.

Shayne

scorp508 · 02-17-2004, 12:39 PM

Get yourself a 86-89 ECM and live in a land of bliss and useful data logging. :jester

B84RADR · 02-17-2004, 12:54 PM

I know that if you go newer on some of these ECM's, you need to switch from a MAF to a MAP system. Can I go any newer on my ECM without having to make that whole change?

scorp508 · 02-17-2004, 01:42 PM

MAP was 90 and 91. You can get the ECM from an 86-89 and swap over. :yesnod: There are a lot of sites on the net showing exactly what must be done and how to re-pin your ECM connectors. You get many more editable features and a hell of a lot more data samples.

B84RADR · 02-17-2004, 01:56 PM

Quote:

MAP was 90 and 91. You can get the ECM from an 86-89 and swap over. :yesnod: There are a lot of sites on the net showing exactly what must be done and how to re-pin your ECM connectors. You get many more editable features and a hell of a lot more data samples.

So no matter what, if I go newer I have to re-pin the ECM connectors? Or is that only if I go newer than an 89?

GRX · 02-17-2004, 01:59 PM

Go here: http://www.eecis.udel.edu/~davis/z28/ecm_swap/

GRX · 02-17-2004, 02:03 PM

Here are deviations from Davis's outline per Bluevette85 awhile back.

Bluevette85
Senior Member
1291 posts [100%]
Latham NY

Title: 870 to 165 Conversion Instructions 5:28 PM 2/6/2003

This seems to be a popular topic recently. I have sent several members my instructions for this so I figured I would post it here.
DISCLAIMER: This worked for me on the stock TPI and on my Superram conversion. You should double check all wiring yourself because it is easy to misconnect something and fry the ECM. Do this at your own risk.

These two sites have information you can use. The davis site has some
errors and I have noted the corrections below.
http://www.chevythunder.com/fuel%20i...%20pinouts.htm
http://www.eecis.udel.edu/~davis/z28/ecm_swap/

The pin changes below are one way only. i.e. A11 gets moved to C12 but C12
does not go to A11.

There are a few connection changes from what davis posted on his site.

870_________165
-------------------------
A11----------------C12
D2-----------------C1
D8-----------------C15
B4------------------D4
+D12---------------D2
C9------------------D11
B11-----------------B12
+D13---------------A11
+D14---------------D16
+D15---------------D15

*Combine the old C15 into the old D14 (which is now the new D16)
*Combine the old D16 into the old D15 (which is the new D15, it doesn't
change)

+ indicates differences in what davis says to do.

The original C12 is a redundent wire and is not connected to anything in the
165.

You can use your 85 MAF without a problem. From what I have read, the 85
MAF can be used in 86-89 but 86-89 cannot be used in 85.

Buy the MAF relay connectors at Napa #EC85, $4.49 each. The two relays are slightly different. The power relay uses all 5 pins but the burn-off uses
only 4 pins. You can use the power relay for both but I used one of each
type. I use the relays for an 86.

There is a six connector plug coming off the 870 ecm wires which goes to the
burnoff module behind the breadbox. You must disconnect this or your
conversion won't work. This plug is lettered and this is what davis calls
the "MAS connector". The relay connectors you buy from NAPA are labeled
ABCDE and you connect everything as follows: (some changes from what davis posted) I put the relay connectors under the dash with the ecm wires so I didn't have to run a bunch of wires into the engine bay.

MAF Burnoff Connector pin A----------MAS pin D
MAF Burnoff Connector pin B----------must run a new line to D12 on ecm connector. You must buy ecm connector pins.
MAF Burnoff Connector pin C----------MAS pin A
MAF Burnoff Connector pin D----------not connected to anything
MAF Burnoff Connector pin E-----------MAS pin A

MAF Power Connector pin A---------MAS pin F
MAF Power Connector pin B---------MAS pin E
MAF Power Connector pin C---------splice into ecm pin B2
MAF Power Connector pin D---------MAS pin D
MAF Power Connector pin E--------- MAS pin A

I tried to use the 870 burnoff module instead of the relays but it wouldn't
work so adding the relays was the only solution.

B84RADR · 02-17-2004, 02:10 PM

GRX, thanks a lot. It looks like this change is without question the best thing to do. I will get my hands on all of the required hardware and read up on it completely. Thanks for taking the time, I appreciate it.

Shayne

B84RADR · 02-17-2004, 02:11 PM

I am assuming that in Diacom, after this switch has been made, I just need to update the letter in my VIN that has to do with the year of the ECM. Correct?

GRX · 02-17-2004, 02:13 PM

Well, I would think you need to use a valid VIN number from a 86-89 corvette chassis. I have contemplated this change but have my hands full at the moment. :cheers:

GRX · 02-17-2004, 02:16 PM

Of course you will need a differnet TunerCATS ECM file as well as a different bins for the chip (which is now a Memcal in the 165 ECM).

scorp508 · 02-17-2004, 02:21 PM

You'll need either the $32 (86), $32b (87-88) or $6e (89) definitions from TC. Then yeah just plug a VIN from a correct year vehicle into Diacom and it'll know what to look for.

B84RADR · 02-17-2004, 02:23 PM

Yeah, I thought about the TC def. file, I'm going to see if they can switch mine out since I just barely bought the TunerCat RT program. We'll see.

GRX · 02-17-2004, 02:35 PM

Geez, ALL those bins work with the SAME ECM? Which bin is better? I mean, if I switch for a 165, then which bin should I go with? :confused:

B84RADR · 02-17-2004, 02:41 PM

If you switch for a 165, you'll need to use a compatible bin with it as well. I plan to just read the chip that comes with the ECM to get a base, or download a base bin file for the proper year to program the chip.

GRX · 02-17-2004, 02:45 PM

Yes, but how will you know which TC def file to purchase? I guess you could send the extracted bin file to TC??

scorp508 · 02-17-2004, 02:49 PM

Quote:

Geez, ALL those bins work with the SAME ECM? Which bin is better? I mean, if I switch for a 165, then which bin should I go with? :confused:

Yup, they all used the 165. If you don't have a 4+3 tranny where you have to keep O/D computer control then I would just jump straight to the 89 code ($6e) as it is the most refined and feature filled.

There are plenty of clean virgin copies of code around here that we can get you. I'd start with a fresh copy of 89 code and start altering things from there. If you have a question about bins let me know. I own all the 165 TC definitions and also have the Bin Decoder that decodes the 4 character BCC on every prom.

GRX · 02-17-2004, 02:54 PM

Sorry sspackman, I don't want to take over your thread here but I need to ask a few questions. :) Scorp, since I do have a 4+3, should I order a ECM for a 1989 that has a 4+3 tranny? I assume I would get a fresh ECM with the proper bin?