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ECU Swap Question, Firing Order?

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Joe Cool

10+ Year Contributor
65
1
Aug 21, 2008
Salt Lake City, Utah
I'm ordering DSM Link really soon and going through ExtremePSI (which I found to be cheapest) I will have to wait up to two weeks to get my ECU back. So I found someone locally who is selling their ECU. It went to a 2g GS-T (mine is a 95 TSi AWD).

I've done searching on this subject already, but my results were partially inconclusive. I was told that since mine is an EPROM (nothing to do with FWD vs. AWD) that I'll need to change my firing order to get the GS-T non-eprom to work in my car. Is this true? I saw some evidence in another thread that claimed that all of the firing orders are the same and that I'll need to change nothing. I do realize that the AWD and FWD make no difference as long as it's the same gen, correct? Although I am a 95 my car is OBDII, not sure if that's a standard occurance or not or if it will make a difference if the car that this came from is either OBDI or OBDII, because it's origin aside from being a 2G FWD is unknown.

Help is appreciated, thank you!
 
What year is the GST ecu? There was a wiring order change, if it is from 95-96 car standard firing order of 4-1-2-3 applies. If I remeber properly the 97+ Ecu in a 95 would require a firing order of 1-4-3-2.
 
As Anger890 said, it all depends what year the GS-T ECU is. The only difference between a 1995 GSX EPROM ECU and a 1995/96 GS-T ECU is R256, a 1K resistor that tells the GS-T ECU to initiate a speed limiter at 130 mph. If you solder a 1K resistor into the missing position the ECU's are identical. You only need to worry about wiring changes if you swap to a 1997-99 ECU, or swap to a 1G cam sensor.
keydiver
 
What year is the GST ecu? There was a wiring order change, if it is from 95-96 car standard firing order of 4-1-2-3 applies. If I remeber properly the 97+ Ecu in a 95 would require a firing order of 1-4-3-2.


I thought that 1 and 4 were on the same coil pack and 2 and 3 were on the same? Wouldn't going from 4-1-2-3 to 1-4-3-2 be the same thing?

Basically, I need to know going from left to right facing the engine on the valve cover what my wires are now and what i need to swap them to. Thank you. It's only temporary so I could care less about how it looks. Remember, swapping a 97 ECU into a 95 car.
 
Yea, youre right about the coil packs. It fires 1/4 and 2/3 at the same time. Even if you had COP ignition, it would still fire both pairs at the same time.

I believe unless you get an EMS, you wont be able to run 4 coil packs, and even then, due to the design of the crank, you couldnt get anything but the above paired firing.
 
You have a 95. Pull your ecu and check to make sure you dont have eprom ecu already.
 
I do have an EPROM which I am shipping out to ECMTuning but to cover me to prevent downtime I'm buying a 97 ECU to swap in. I'm not trying to be difficult but I just need a direct answer to my question in the manner I asked it.

Thank you!
 
Just swap the wires at the coilpack. Take both wires from the one coilpack and move them to the other. Or, swap plug wires 1&2, and 3&4. Or, you can swap pins 10 & 23 at the ECU.
But, to make the car idle right and not have any driveability issues you will also have to swap injector wires. Some guys have tried the injector wire swap suggested in the Magnus 1gina2g pdf, but the car still runs rough. Those instruction are made for using a 1995 ECU in a 1997+ car, just the opposite of what you are trying to do. Normally the injector pins at the ECU are:
pin #1 - cylinder 1
pin #2 - cylinder 3
pin #14 - cylinder 2
pin #15 - cylinder 4

I'd like someone to try this combination to see if it give a good idle with a 1997+ ECU in a 1995/96 DSM:
pin #1 - cylinder 2
pin #2 - cylinder 1
pin #14 - cylinder 4
pin #15 - cylinder 3

Keydiver
 
I do have an EPROM which I am shipping out to ECMTuning but to cover me to prevent downtime I'm buying a 97 ECU to swap in. I'm not trying to be difficult but I just need a direct answer to my question in the manner I asked it.

Thank you!

Oh okay,

Sorry I didn't realize that.
 
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