I can see on line some how to's for interpreting the data that comes out of the ECM. But some things are not clear..
I have a (new to me) 87 4cyl manual (with 88 engine), that I only get to every 2 weeks, as I am working on it at a friends. So I cannot just run out and examine it. But the internet seems to indicate that the 160bps data is not the same on the 87-88 manual 4cyl. Or they say "not compatible". Is there a reason for this?
I bought a 1227748 ECM from a Buick Century, with ASAW software, not realizing that the Fiero had different software.. and alas, the data that comes out of this one is 8192bps, and clearly not the 20 bytes of the Fiero.

Question 1.. does the 87-88 manual 4cyl ECM data spew out the same 160bps, 20 bytes?
Question 2.. if I look at all 160 bps data streams from all Fieros, is it the same? One would expect a difference in the Torque versus shift up status, but are the data streams the same otherwise?
Question 3.. is the data stream present in all of the diagnostic modes, including no diagnostic mode? IE no resistor or short, and data still comes out?

Unsure about question 1. I believe they're all 160 baud.
The data streams are similar between the years, but may have subtle differences based on broadcast code.
The resister may not have to be used in all instances. My 85 didn't need a resister and steamed info all the time, i had to short the terminals to get the advance to bypass, however, an 86 I worked on needed the resister to start streaming and also went into a different mode, changed idle speed and no advance.

Since then, I've started messing with the 7730 ecm with 8192 baud. There's a lot more data and control both in data output and in bin manipulation.

Here is a post that covers some of these issues,
https://www.fiero.nl/forum/A...130314-2-121381.html
and you can see that sometimes the data comes out all the time, and sometimes you have to apply the resistor.
If you apply the wrong resistor, the car would not even run right, as it bypasses the ECM timing.
So clearly, different ECM versions behave differently. Sigh. It would be nice to have it work the same, every time.
When I have my own '87 back here, in the next week or two, I will post on how it behaves right away.

A1 - No
A2 - No
A3 - From what I have found you will always need the 10K resistor to have the data flowing.

If you are looking to scan your 87-88 2.5 and already have a cable that works with it, download my disk, install TunerPro RT and use the .adx file I have modified to work with the 87-88 2.5 Fiero.

The disk can be downloaded here - http://www.reddevilriver.com/aldl.html - The link is the yellow box at the bottom of the page. This is also the page you can purchase a cable if you don't already have one.

On the disk is a directory of .adx files. The one for the 87-88 2.5 Fiero is 1987 - 88 2.5 Fiero 1227748 $48.adx

Note - TunerPro works 100% after a 10 second 'nag' screen. You can purchase a license and avoid the nag screen however that is never required.

I appreciate that, but I am trying to create an embedded processor project that does the work. Not trying to put a PC in the car. So can you share any details about the data? If it is not similar, that probably makes it 8192. Is it the same data, but at a faster rate? The cable is not an issue, I am putting circuits together to do the conversions.

8192

Download the disk, install TunerPro, select the Fiero 2.5 ADX and use the Edit ADX function to see how the data is arranged in the stream.

You can flash a 27SF512 chip with the Fiero chip's data.

You do have to poll the data - ie you have to send a 'request' header and then the ECM replies with a single data stream. Once you receive it you then send another request.

Request stream - 0xF0 0x56 0x01 0xB9

Reply stream header - 0xF0 0x95 0x01

[This message has been edited by phonedawgz (edited 05-16-2016).]

I get it, thanks for the idea. I will do that..