Changing to 1228079 questions.
09-03-2013, 05:09 PM
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Changing to 1228079 questions.
Hello everybody,
I want to change my '81 vette with CCC E4ME quadrajet to the newer 1228079 (as I have more control on the timing curve etc etc with the newer ecm). I bought two 1228079's from ebay about 5 years ago but as I'm busy with other projects this one is laying low. At this moment I think my OEM ECM is running at his last legs so a perfect moment to step further into this project.
I also bought an '88 caprice monte carlo service manual so that isn't a problem.
As I opened up both ECM's I noticed that the layout is different.
First ecm:
Second ecm:
When I look at this topic about the 1228079...
https://www.thirdgen.org/forums/diy-...-diagrams.html
When looking at his pictures I would think my first ECM is for the LG4/L69 with non ecm controlled airco and my second ecm iswas for the LV2 engines. Anybody thinking differently?
As my current ecm isn't controlling the airco I think going with the first ecm is the logical choice I think
I cross referenced both ecm connector pages and wiring diagram pages and this is what I found.
All wire colors didn't change!
Yellow didn't change.
Orange moved from one terminal to another (in black the previous terminal on my 81 connector)
Red is new
Grey is not going to be used.
I want to use the ZZ4 prom as a base setting and go from there. I already have the .bin file both with and without ESC. As I currently don't have ESC I'll go with the "without ESC" prom.
On the biggest connector I need to change the EGR wire from terminal T to #19 (it's disabled in the prom so no real need for it)
On #1 I need to find an Baro sensor as my ECM is only using an vacuum sensor right now (not to difficult I think)
As my AIR system is still in place but I don't needed it I don't really need terminal #4 and B but as they are in the right place already I'll just leave them there. Is this ECM going to throw a code if the AIR system isn't working (but still connected)?
Then the small connector.
Terminal E, my engine now has a idle control solenoid only to compensate for the airco kickin in (not ecm controlled). Would it be a problem if I leave terminal E unused?
Terminal L as I'm using the non ESC prom no need to connect it. So that problem is solved!
Terminal M has some black ?? in front of it as my current wiring harness has a white wire in there that isn't in the diagrams (very nice...)
Terminal N is high gear input I need to move that from terminal 17 in my harness.
And the last Terminal T, the canister purge solenoid. I also have the canister in my car but isn't ecm controlled. Would this give a code or ses if it wasn't hooked up?
The wiring diagram.
I need to hook up the Baro sensor, as the vacuumsensor is close by not a big problem.
My current VSS gets 8v from the ECM and I need to change that to 12v from ignition also no problem.
Throttle solenoid?
Canister purge solenoid?
I also have the SES light but not the lamp driver module. On my '81 the SES light ground is directly controlled by the ECM. Do I really need the lamp driver module to get it to work? As I see it in the wiring diagram there is an extra 12v source going in. One exits to the ECM ground the second one is a dead end at the ALDL terminal D and the third exits also to ALDL terminal A (ground)
I hope somebody can help me with this
Greetings Peter
I want to change my '81 vette with CCC E4ME quadrajet to the newer 1228079 (as I have more control on the timing curve etc etc with the newer ecm). I bought two 1228079's from ebay about 5 years ago but as I'm busy with other projects this one is laying low. At this moment I think my OEM ECM is running at his last legs so a perfect moment to step further into this project.
I also bought an '88 caprice monte carlo service manual so that isn't a problem.
As I opened up both ECM's I noticed that the layout is different.
First ecm:
Second ecm:
When I look at this topic about the 1228079...
https://www.thirdgen.org/forums/diy-...-diagrams.html
When looking at his pictures I would think my first ECM is for the LG4/L69 with non ecm controlled airco and my second ecm iswas for the LV2 engines. Anybody thinking differently?
As my current ecm isn't controlling the airco I think going with the first ecm is the logical choice I think
I cross referenced both ecm connector pages and wiring diagram pages and this is what I found.
All wire colors didn't change!
Yellow didn't change.
Orange moved from one terminal to another (in black the previous terminal on my 81 connector)
Red is new
Grey is not going to be used.
I want to use the ZZ4 prom as a base setting and go from there. I already have the .bin file both with and without ESC. As I currently don't have ESC I'll go with the "without ESC" prom.
On the biggest connector I need to change the EGR wire from terminal T to #19 (it's disabled in the prom so no real need for it)
On #1 I need to find an Baro sensor as my ECM is only using an vacuum sensor right now (not to difficult I think)
As my AIR system is still in place but I don't needed it I don't really need terminal #4 and B but as they are in the right place already I'll just leave them there. Is this ECM going to throw a code if the AIR system isn't working (but still connected)?
Then the small connector.
Terminal E, my engine now has a idle control solenoid only to compensate for the airco kickin in (not ecm controlled). Would it be a problem if I leave terminal E unused?
Terminal L as I'm using the non ESC prom no need to connect it. So that problem is solved!
Terminal M has some black ?? in front of it as my current wiring harness has a white wire in there that isn't in the diagrams (very nice...)
Terminal N is high gear input I need to move that from terminal 17 in my harness.
And the last Terminal T, the canister purge solenoid. I also have the canister in my car but isn't ecm controlled. Would this give a code or ses if it wasn't hooked up?
The wiring diagram.
I need to hook up the Baro sensor, as the vacuumsensor is close by not a big problem.
My current VSS gets 8v from the ECM and I need to change that to 12v from ignition also no problem.
Throttle solenoid?
Canister purge solenoid?
I also have the SES light but not the lamp driver module. On my '81 the SES light ground is directly controlled by the ECM. Do I really need the lamp driver module to get it to work? As I see it in the wiring diagram there is an extra 12v source going in. One exits to the ECM ground the second one is a dead end at the ALDL terminal D and the third exits also to ALDL terminal A (ground)
I hope somebody can help me with this
Greetings Peter
10-30-2013, 09:17 PM
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Car: 1984 Trans Am
Engine: 305 L69 (E4ME)
Transmission: NWC T5 1352-072
Axle/Gears: 3.73 (6HS)
Re: Changing to 1228079 questions.
I am running a E4ME carb. I am finding out that there is not a lot of info on the ecm/prom for the carb models like there is for the injected models. I am trying to figure out what all the chips do on the board. Thinking of putting in a 350 down the road. Anyway, I have three ecms.
Two are ecm 1226455. The original for my trans am, vin G, that I am using and one I got out of a 84 monte carlo vin H. It looks a lot like your second picture that you posted for the 1228079. Here is the picture I took of the 1226455 out of the monte carlo.
The second ecm, I got was out of a 1987 trans am, vin H, that had a stock E4ME carb. I pulled the vin and it said it was a stock carbed car. Anyway, I pulled the ecm and it did not have a label on it and had a jet prom. Looks a lot like the 1228079 in your first pic. Here is a pic.
Two are ecm 1226455. The original for my trans am, vin G, that I am using and one I got out of a 84 monte carlo vin H. It looks a lot like your second picture that you posted for the 1228079. Here is the picture I took of the 1226455 out of the monte carlo.
The second ecm, I got was out of a 1987 trans am, vin H, that had a stock E4ME carb. I pulled the vin and it said it was a stock carbed car. Anyway, I pulled the ecm and it did not have a label on it and had a jet prom. Looks a lot like the 1228079 in your first pic. Here is a pic.
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