replacement ECM (or ECU?) for my '95 Wagon

[billmorrow]

I hear you. I'm still debating throwing a carb on one of my LT1s. Also getting lazy in my old age and prefer cavernous & un-cluttered engine bays.
FWIW while you are learning about the opti, if you also learn how to read data logs (need a communication cable & laptop, software is free) then LT1s aren't so difficult.

reading the data log IS easy once you find it.. in my '87 allante the codes were read through the climate control if my memory is correct, on a small digital readout.. sold that car about 18 years ago.. still have pix, someplace..
reading OBD1 codes on the '92 buick is counting beeps or flashes or something and shorting a couple of pins on a connector whose whereabouts are a mystery to me..
have a lot of laptops, read my sig line..
was on a site where the software was $500+ to thousands.. not so free, that.. 🙂
read the codes on both my '95's and both had 16 set, which points to the opti..

also, just for interest, i ordered an opti for the LT1 engine for $50 on amazon..

https://www.amazon.com/gp/product/B07S3YR9YR/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

arrives sunday..

 

[Dirtybob]

pulling codes is not a data log.

logger screenshots:

 

[billmorrow]

nice graphic..
looks to have been written in visual basic or similar..
that for the OBD1 or OBD 1.5 or OBD2 and is that software package freeware..?
if so where can i get the cable andsoftware package..? 🙂
thanks..

 

[HotZ28]

nice graphic..
looks to have been written in visual basic or similar..
that for the OBD1 or OBD 1.5 or OBD2 and is that software package freeware..?
if so where can i get the cable andsoftware package..? 🙂
thanks..

OBD Diagnostics

aldlcable.com

TunerCat

 

[2007LucerneCXL]

See post #38.

 

[billmorrow]

See post #38.

thanks, have seen that cable source.. the software is still a bit high cost for just one or two cars.. 🙂

 

[2007LucerneCXL]

Freeware is on the site, so not sure if you can get much cheaper!

 

[billmorrow]

Freeware is on the site, so not sure if you can get much cheaper!
View attachment 31480

maybe i did not look closely but did not see the freeware application..
will look again, a lot to look through.. 🙂
i just do not see the freeware part.. datacat is $70
i can not make out anything on the graphic in your post..
perhaps you have a link or i could be at the wrong site..?

 

[2007LucerneCXL]

It's all listed in this link on the site, but you may have to spend some time looking at the individual software programs.

OBD Diagnostics

aldlcable.com

 

[billmorrow]

It's all listed in this link on the site, but you may have to spend some time looking at the individual software programs.

OBD Diagnostics

aldlcable.com

got it, thanks..
interesting what one can do reprogramming the ECM and other controllers on these cars..
if the opti replacements don't sort out both '95's these tools will sure help point to the root causes..

 

[Dirtybob]

eehack is the free logger software (LT1 specific). $EEHack – fbodytech
Tunerpro is also free but is mainly for editing bin files IIRC it will not log an 8051 pcm. It does do a nice job of logging obd1 cars. Might be of some use with your '92 wagon.

 

[billmorrow]

eehack is the free logger software (LT1 specific). $EEHack – fbodytech
Tunerpro is also free but is mainly for editing bin files IIRC it will not log an 8051 pcm. It does do a nice job of logging obd1 cars. Might be of some use with your '92 wagon.

THANK YOU for the links..
FWIW a .bin file is, or should be, a binary file (thus the .bin), not a program, just a file with each line separated by a CRLF (carriage return line feed) and is, or was, read by a command processor which was just like keyboard input to a program..

SO! what is an 8051 pcm..? 🙂

what i am taking from this conversation is that the .bin file is read by the ECM which is thus programmed to run the engine in whatever fashion the .bin file wants it to run..?!

another FWIW, i got the $50 optispark today, borrowed the thin wall torx socket at the repair shop, took it apart and i can see TWO vacuum ports, at least i THINK they are both vacuum and not one vacuum and the other supplying air.. filtered air one would hope and not outside dirty air.. and i can see how this thing can get dirty with the vacuum being applied sucking in dirty, moist, oily air if not sealed with more than what is supplied..
pix supplied if asked..

 

[Dirtybob]

The 8051 pcm is the 'LT1' brainbox.
Yes, the bin file is the 'tune'

there should be two vent lines from your opti. One will have a one way check valve which runs to the manifold and the other attaches to the intake elbow.

 

[billmorrow]

After spending a LOT of $$ for different optispark distributors purported to fit the 1995 Roadmaster LT1 cars i have found the following:
Accel brand, MTC brand and, apparently all others, ranging, i am guessing, from those with prices from about $45 to $375 (Accel brand) are ALL made in china.. they all sure look alike.. same numbers on the machined casting and plastic parts that HAVE any sort of number.. SO FAR..
the one $49 one from amazon has a no name or country of manufacture on the optical sensor.. i have NOT YET opened the MTC version (the screws are covered with paint) i have here to see if the optical sensor was branded of a no brand like the $45 item..
so if i open it up it is mine and not returnable..
no one seems to know if the reductor plate screws have thread locktite (NOTE: the $45 one i disassembled had those screws only hand tight)..
i do not know if the reductor plate number of slots is the same on those units speced for different 7 Liter V8 engines..
if you were to look at these on amazon you will see wild variations of price on units that all appear to be the same.. even those that are supposed to fit the '95 RM cars..

 

[billmorrow]

just to finish this thread, i pulled the blue '95 from the guys who had done no work on it for months, took it to another shop, it was done in a week, new optispark installed and it is now running..
the symptoms were it would stop when warmed up..
today i took the old optispark apart and found the optical sensor coated with what looks to be clean motor oil.. the cable also looks like it was burned and the plug showed signs of high heat..
it was also different from all the newer rebuilt or aftermarket optispark units i have taken apart these last weeks..

car ran well when i brought it home on thursday, about 15 miles.. took it for a spin to warm it up and after a mile+ it just stopped dead.. coasted to a stop and it fired right up and ran another few miles no problem..

thanks to all for the education on the optispark.. good idea poorly executed by GM, IMO..

 

[Dirtybob]

Car stalling sounds as if it could be a loose connection at the opti pigtail or the ICM. A wiggle test (of the connectors/wiring) while idling may reveal the culprit. Also a chance your ICM is going bad, they tend to fail when heated right before they fail entirely. Even if new. If the module is made by wells/airtex start looking for another one...
Doesn't help when many parts stores throw returned items back on the shelf for resale (looking at you Autozone).

 

[billmorrow]

Car stalling sounds as if it could be a loose connection at the opti pigtail or the ICM. A wiggle test (of the connectors/wiring) while idling may reveal the culprit. Also a chance your ICM is going bad, they tend to fail when heated right before they fail entirely. Even if new. If the module is made by wells/airtex start looking for another one...
Doesn't help when many parts stores throw returned items back on the shelf for resale (looking at you Autozone).

the OS was, as i said above, oily inside.. looked to be clean motor oil.. but wet all around the reductor(?) wheel..

ICM..? just guessing: ignition control module..?
is that the same thing as the ignition coil aka coil pack..? if so, it was already replaced..
the car drove fine from the shop to home, about 15 miles..

 

[HotZ28]

The ignition control module (ICM) & coil are two separate parts. I have owned plenty of LT1's and always spaced the ICM with washers about 1/4" from the head to eliminate heat failure from the head. After that simple modification, I never had another ICM failure!

 

[Dirtybob]

Right, I don't think I've ever had a coil failure (not counting coil pack/cylinder cars). Have had plenty of ICM failures/malfunctions in everything from HEIs to the distributorless setups. Wells brand modules fail with alarming regularity, I once received three bad ones in a row (all new in box). Thought I was losing my mind and took the car to one my professional mechanic friends for a second opinion. 3 hrs. and $210 later, he confirmed the ICM was faulty. Purchased a (not wells brand) ICM from another parts house and all was good. Store manager didn't want to refund me on the wells module until I (less than politely) asked him if he was willing to pay my mechanic's diagnostic fee.
FWIW, did the ICM spacer mod on my LT1. Can't confirm it helped but it sure didn't hurt (cheap insurance).

 

[billmorrow]

Right, I don't think I've ever had a coil failure (not counting coil pack/cylinder cars). Have had plenty of ICM failures/malfunctions in everything from HEIs to the distributorless setups. Wells brand modules fail with alarming regularity, I once received three bad ones in a row (all new in box). Thought I was losing my mind and took the car to one my professional mechanic friends for a second opinion. 3 hrs. and $210 later, he confirmed the ICM was faulty. Purchased a (not wells brand) ICM from another parts house and all was good. Store manager didn't want to refund me on the wells module until I (less than politely) asked him if he was willing to pay my mechanic's diagnostic fee.
FWIW, did the ICM spacer mod on my LT1. Can't confirm it helped but it sure didn't hurt (cheap insurance).

is this what we are talking about..? this from the web site of a local auto parts store..
i have not yet searched other sites like amazon, et al..