Georgia Fiero Club Forum

All Things Fiero => Expert Tech Advice => Topic started by: MikeMac on February 08, 2020, 10:08:01 pm

Title: Engine wiring harness differences
Post by: MikeMac on February 08, 2020, 10:08:01 pm: Can a 4 cylinder engine harness be adapted to a V6 relatively easily? Maybe extending a few wires or totally different?
Title: Re: Engine wiring harness differences
Post by: GTRS Fiero on February 08, 2020, 10:27:06 pm: What year 4-cylinder? '85-'86?
Title: Re: Engine wiring harness differences
Post by: MikeMac on February 08, 2020, 10:36:04 pm: 1987 Duke into a 1988 that is currently a Series 1 supercharged but was originally a 4 cylinder. Looking to possibly go to the 2.8/3.4
Title: Re: Engine wiring harness differences
Post by: GTRS Fiero on February 08, 2020, 10:38:48 pm: Going to use DIS on the new engine?
Title: Re: Engine wiring harness differences
Post by: MikeMac on February 08, 2020, 10:39:53 pm: Quote from: MikeMac on February 08, 2020, 10:36:04 pm
1987 Duke into a 1988 that is currently a Series 1 supercharged but was originally a 4 cylinder. Looking to possibly go to the 2.8/3.4

I believe the original 4 cylinder harness was what was modified to the 3800 if my memory serves right. I have the conversion manual somewhere around here. It was a kit from ACE in Texas
Title: Re: Engine wiring harness differences
Post by: MikeMac on February 08, 2020, 10:40:42 pm: Quote from: GTRS Fiero on February 08, 2020, 10:38:48 pm
Going to use DIS on the new engine?
eventually, but would go with a distributor at first.
Title: Re: Engine wiring harness differences
Post by: scottb on February 09, 2020, 08:08:30 am: I might be wrong on this, but I believe that both 87 and 88 2,5s were DIS
Title: Re: Engine wiring harness differences
Post by: TopNotch on February 09, 2020, 08:30:12 am: Quote from: scottb on February 09, 2020, 08:08:30 am
I might be wrong on this, but I believe that both 87 and 88 2,5s were DIS
Correct.
Title: Re: Engine wiring harness differences
Post by: GTRS Fiero on February 09, 2020, 08:35:03 am: Which is why I asked, '85-'86. It would seem to be easier to stick with DIS.
Title: Re: Engine wiring harness differences
Post by: Raydar on February 09, 2020, 09:04:58 am: I don't know anything about the early Duke harness, but considering the amount of research and fabrication required, I would probably be inclined to just source a V6 harness. I have done a Duke to V6 swap in an 88 coupe. With the proper harness, it's completely plug n play. (Unless ACE modified your wiring inside the car.)
Title: Re: Engine wiring harness differences
Post by: TopNotch on February 09, 2020, 09:11:24 am: BTW, i have an 85 V6 harness. If anyone wants it, you're welcome to it. I understand there are minor differences between 85 and later harnesses, such as how the trunk light is wired.
Title: Re: Engine wiring harness differences
Post by: Raydar on February 09, 2020, 09:22:38 am: Quote from: TopNotch on February 09, 2020, 09:11:24 am
BTW, i have an 85 V6 harness. If anyone wants it, you're welcome to it. I understand there are minor differences between 85 and later harnesses, such as how the trunk light is wired.

Is the 85 trunk light part of the engine harness? In the later cars, it's part of the tail light harness.
If it's a manual harness, it will be missing the reverse light wiring, since the switch for the 4 speed was on the shifter.
Title: Re: Engine wiring harness differences
Post by: MikeMac on February 11, 2020, 11:51:02 am: Quote from: TopNotch on February 09, 2020, 09:11:24 am
BTW, i have an 85 V6 harness. If anyone wants it, you're welcome to it. I understand there are minor differences between 85 and later harnesses, such as how the trunk light is wired.

I would take that harness from you. Thanks Pat
Title: Re: Engine wiring harness differences
Post by: Fierofool on February 11, 2020, 12:15:07 pm: The 85 trunk light harness runs underneath the left rear fender and is probably a part of the tail light harness. The switch wiring for the trunk light comes through the side fenderwell from that harness.