I'm swaping my 4 spd on my duke for a 5 spd.
Does the ecm care which manual tranny is bolted on? ...5 spd getrag, 5 spd isuzu or 4 speed? The mechanical stuff is no problem, but I have to make sure w/ the electrical compoents.

In order for the swap to work well do I have to modify my ECM or get a new one, or can I just keep my original?

Thanks, and God bless ya

Michael

[EDIT: typo, clarification]

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"A guy know's he's in love when he loses interest in his car for a few days." -Tim Allen

He who dies with the most toys... still dies.


Check out my restoration!

[This message has been edited by Fierology (edited 06-15-2008).]

quote Originally posted by Fierology: ...I have to make sure w/ the electrical components. In order for the swap to work well do I have to modify my ECM or get a new one, or can I just keep my original? Thanks, and God bless ya Michael [EDIT: typo, clarification]

I know your reverse wiring will change and no longer be at the shifter. I don't have both cars here with me to compare and contrast between wiring harnesses on '6156 ECM cars versus 6864 ECM cars. There are differences in the harnesses I know.

You might want to try the old ECM first to see if you can get away with it. There are differences in the engine wiring harnesses of 85-86 coupes (like the oil pressure stuff to the gauge cluster, coil connectors, and ignition module connector for very basic examples) that will have you changing a lot of stuff if you swap ECMs.

I think all you need to change is the PROM chip in the computer and all that does is run the shift light. It won't really matter going from 4spd to 5 spd. I put a ECM in my first 84 4spd once that had a 5spd PROM in it and the upshift light was trying to tell me to shift into 5th gear.

wEiRd, I've never heard of an upshift light before. It seems kinda dumb to me.
Does it just turn on when the rmp gets high enough so you don't damage your engine?

also, BUMP!

=Michael

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"A guy know's he's in love when he loses interest in his car for a few days." -Tim Allen

He who dies with the most toys... still dies.


Check out my restoration!

https://www.fiero.nl/forum/Forum1/HTML/065759.html

You don't need to swap the ECM for the 5-speed to work. You do need to splice a new set of wires into the reverse switch line and run them back to the new tranny however.

What Toddster said^ ^ I've done the change twice and used the 4-speed ECM. Right now, getting 28-33 out on the road with a V6 and air.

Awesome. Thanks guys. You all give great help as always.

:-D

-Michael

------------------
"A guy know's he's in love when he loses interest in his car for a few days." -Tim Allen

He who dies with the most toys... still dies.


Check out my restoration!

quote Originally posted by Fierology: wEiRd, I've never heard of an upshift light before. It seems kinda dumb to me. Does it just turn on when the rmp gets high enough so you don't damage your engine? also, BUMP! =Michael

So you have never owned a manual Fiero before?

I'm on my first, but it was in such bad condition when I first got it, I'm still rebuilding it. I plan to be done by the end of August, God willing.

-Michael

------------------
"A guy know's he's in love when he loses interest in his car for a few days." -Tim Allen

He who dies with the most toys... still dies.


Check out my restoration!

A lot of owners pulled the bulb on the upshift light. I did--got tired of it telling me what I already knew.

Actually the shift light is load based(MAP/RPM)... so when you are accelerating hard it will stay off longer... if slowly pulling away it will come on sooner. Its meant to help you get better fuel economy

Edit: DOH! Old thread...

[This message has been edited by carbon (edited 03-20-2009).]