World's slowest Fiero/Quad 4 Swap (Page 51/51)
Quadfather JUL 21, 02:19 PM

quote
Originally posted by fieroguru:


Do you want your harness to have splices on every ecm wire?

My preferred method is to depin the entire ECM connector(s), cut the wires to match the new routing, then crimp on new pins at the ECM connector. This keeps splices in the harness to a minimum (like GM intended).

At the 203 connector, with new pins, you can normally crimp 2 wires into the pins and avoid a splice mid-wire.



I understand what you’re saying and I agree that’s the professional way of shortening the harness to fit the Fiero, but what I’m talking about is the step before then. I’m still trying to mate the Beretta’s ECM and engine wiring harness to the Fiero.

The mistake I think I was making was removing specific pins from the Beretta ECM plug and moving those wires to the C203 or C500, instead of adding a connection to those wires. In other words, if a wire is attached to a plug at the ECM, I need to keep that wire there (regardless of how I eventually shorten it). When the C203 or C500 calls for a certain wire, I need to find a Beretta wire that is on a plug that won’t be used in the Fiero, or add a connection to a wire that plugs into the ECM.

[This message has been edited by Quadfather (edited 07-21-2025).]

Quadfather JUL 27, 05:18 PM
Maybe, just maybe, I'm getting this figured out. I've gone back through the wiring diagrams and found three wires I mistakenly unplugged from the Beretta computer. Now I'm waiting for replacement pins to arrive. I bought 75 of these because they're so cheap. Hope they're the correct parts.



The whole thing is still a rat's nest.



Once I get the new pins and restore the wires to the Beretta plugs, I'll start winnowing this out. Part of that challenge will be figuring out the small plug on the Fiero that's adjacent to the C203.





I don't remember ever seeing this plug identified in any of my diagrams, so I'll have to check them again. The Beretta version of it still has both sides.



It's difficult to describe how uncomfortable the weather is in Oklahoma right now, so spending time in the shop is real challenge. I'll be on vacation next week so no progress for a while.
Quadfather JUL 27, 05:23 PM
While running an errand Saturday morning I came across a little car show as part of Oologah's Frontier Days event. It included what was my dream car for decades, a blue, 1970 GTO Judge with the 4-speed transmission and a Hurst shifter.



And, of course, a 1987 Fiero GT.



Had a really nice conversation with the owner. It has an Indy interior that's just beautiful. He wishes it was a manual car, but still loves it. Understandable.