Resolved 90 to 91-94 NA ECU Conversion?

[tacomaryno]

To start I did a couple of searches and found a couple of write-ups on this, they were very confusing. So many guys say different ways of doing this. I'm just looking for one simplified way of doing it and the parts I need from the donor car.

I guess an even bigger question is if my ECU is fine would it even make a difference in power with this swap? My goal is to get an EPROM ECU and get her tuned up a little more. I would assume I have a better chance of finding a 91-94 NA EPROM ECU than I would just a 90 ECU.

SIDE NOTE: the stock dash and gauge cluster has been removed, I run 3 gauges - volts, water temp, oil pressure and an aftermarket 5 in tach that is already spliced into the wire from pin 21 and works great. I know there's something about swapping a pin to fix the stock tach which I don't have, not sure if I would still be effected.

I have a 90 Eclipse that I race on the dirt ovals. My class is "stock" and no turbos allowed. All my mods are listed in my profile. Maybe an EPROM ECU would have a better effect on these mods?
Thanks for your help in advance.

OK I think I have this figured out so correct me if I'm wrong.

All I need is the 91-94 power transistor and it's plug (and of course the 91'+ ECU).
1-First I take the Thicker gauge black/white wire from the 91'+ transistor plug and splice it into the black/white wire on the 90' 4 wire coil plug (this is the main ignition wire).
2-I then connect the corresponding color wires from the 91'+ plug to the existing wires (yellow/green, yellow, black, yellow/red, yellow/black).
3- There is now a white wire left on the 91'+ plug. It needs to be ran all the way to the ECU pin #109. Pull the existing wire (it will no longer have use) and plug in the white wire from the plug to pin #109.
4- Plug into 91'+ power transistor and mount.
5- For NON TURBO, move pin #6 to pin #14. (most write-ups say swap pin 6 and pin 14 but the 90' non-turbo ECU doesn't have a wire running to pin 14)
6- Plug in ECU, wipe the sweat off your brow, slow your heartbeat because you hate wiring and you just know you probably screwed something up. Start her up, fingers crossed.

Does that sound about right?

Now since I have an aftermarket tach spliced to pin #21 CAS (rpm), is it a must to run the white wire to pin #109 in step 3?

 

[tsigreg]

Is it possible to run a turbo ecu in a nt I've never heard of it being done our did they make eprom nt ecu

 

[Arthris]

To run a turbo ecu in a n/t is pointless. You would need the injectors fpr maf knock sensor to do it. As for the swap i know the turbos u swap the two pins for the maf reset. I would expect that if u plugged in the 91-94 ecu that it should just start up. And yes a eprom would be better as you can either burn ## own chips or run a ostrich to tune

 

[steve]

5- For NON TURBO, move pin #6 to pin #14. (most write-ups say swap pin 6 and pin 14 but the 90' non-turbo ecu doesn't have a wire running to pin 14)

The non-turbo cars don't have a MAF reset line so there isn't a wire to swap just move the Idle Position Sensor. The rest of the 90 to 91 conversion is to make the factory tach work which you don't need.

Just locate a EPROM NT ECU and socket it.

 

[tacomaryno]

The non-turbo cars don't have a MAF reset line so there isn't a wire to swap just move the Idle Position Sensor. The rest of the 90 to 91 conversion is to make the factory tach work which you don't need.

Just locate a EPROM NT ECU and socket it.

So skip all the power transistor stuff, move 6 to 14 and I'm set? Thanks Steve

Is my best bet to send one off, have it socketed and have a chip installed for what I'm running and how I'm running it?

Also is the 390cc AT Turbo injectors too much for my application if I go EPROM?

 

[92AWDHX40]

I would send it off and have what you need done to it, switch the pins if you have a 90 ecu to a 91 to 94 i believe been a while since i swapped ecus.

 

[tacomaryno]

I forgot to get back...... works like a charm!!