1990 Non Turbo ECU in a 1991 Non Turbo

[Turblown]

My 1991 non turbo ecu (MD166255) is fried from capacitor leakage . I found a 1990 non turbo ecu (MD128624) in good condition for a good price. I went to switch wires #6 (green/white) and #14 (green) and found that wire #6 was empty. All I could do is put wire #14 (green) in the spot for wire #6 (empty). So now I have a green wire in position #6 and position #14 is empty on my 1990 Non Turbo Ecu. The references I have below are conflicting on this point and I haven't read any posts on an empty pin location for wire #14 on 1990 wiring (wire #6 on 91-94 wiring). My only confidence lies in that the car seems to be running fine, and that the first reference looks like a page from the service manual.

1990 Non Turbo Wiring Diagram (#14 is empty)
1990 and 91-94 ECU Wiring (#14 - airflow sensor)

Is pin #14 in the 1990 wiring diagram (pin #6 in the 91-94 diagram) the extra wire needed for the turbo MAF only?

I have read up on turbo conversion and know you need a total of 7 wires running to the turbo MAF and since this location is listed as "air flow sensor" it would make sense that this wire would only be found on a turbo wiring harness.

Any input would be great. Steve or Mavisky, if you are out there, your expertise would be appreciated. Thanks.

 

[steve]

Is pin #14 in the 1990 wiring diagram (pin #6 in the 91-94 diagram) the extra wire needed for the turbo MAF only?

The non-turbo cars don't have the MAF reset signal. That is why you only have one wire to move.

 

[Turblown]

Sweet! That's all I needed to hear. This is good info to have for the non turbo dsm's out there.

 

[mavisky]

Sweet! That's all I needed to hear. This is good info to have for the non turbo dsm's out there.

But it's bad because the nt ecu doesn't monitor knock and runs totally different fuel and ignition maps as it's expecting high impedance 260cc injectors not low impedance 450cc injectors.

Sorry.

 

[Turblown]

But it's bad because the nt ecu doesn't monitor knock and runs totally different fuel and ignition maps as it's expecting high impedance 260cc injectors not low impedance 450cc injectors.

No, I'm not doing the turbo swap (not yet). I'm just replacing a non turbo ecu with another non turbo ecu. I have the stock NT injectors, etc. So the empty pin positions are okay. I do plan on going turbo soon (hence the parts car), but I want to make sure I have a decent running daily driver before I mess with anything. I'm sure you'll hear from me again during the swap. Thanks!

PS - I think I read that you ran a NT with turbo ECU, 450cc, turbo Maf, turbo fuel pump, etc for a while without adding the turbo yet. I think I'd like to try that for a while to take it one step at a time, as long as I can still keep it a DD.

 

[mavisky]

No, I'm not doing the turbo swap (not yet). I'm just replacing a non turbo ecu with another non turbo ecu. I have the stock NT injectors, etc. So the empty pin positions are okay. I do plan on going turbo soon (hence the parts car), but I want to make sure I have a decent running daily driver before I mess with anything. I'm sure you'll hear from me again during the swap. Thanks!

PS - I think I read that you ran a NT with turbo ECU, 450cc, turbo Maf, turbo fuel pump, etc for a while without adding the turbo yet. I think I'd like to try that for a while to take it one step at a time, as long as I can still keep it a DD.

Yea I did that. It got about 12 mpg and wouldn't rev right above 4500rpm.

I saw the name Turblown so assumed you were trying to replace your turbo ecu with an nt ecu.

 

[Turblown]

Yea I did that. It got about 12 mpg and wouldn't rev right above 4500rpm.

I saw the name Turblown so assumed you were trying to replace your turbo ecu with an nt ecu.

Ahh... sounds like it is an all or nothing swap eh? I've got a parts car ready. I can do it all at once, but space and time are limited. When I do it, it's gotta be a sure thing.

Yeah, I chose my username when I had a 1g FWD turbo as my DD, but I sold it. One day my username will ring true again, but not yet.