I have a '91 Firebird Formula LB9/auto. and bought a NEW sp350/357 (L31w/ higher lift cam), I am not 100% on which intake i'll use and and concerned with the OLD wiring, plugs/pig-tails, sensors. Alot of the 30+ yr old wiring/plugs are showing their age, (some burnt, some exposed, some broken, ) and appears to be a few places that were "hacked/spliced". I am wondering if there is a VENDOR or option for replacing. I am just learning, and its my FIRST swap so its daunting and intimidating. Is it better to cut and piece the BAD w/wire and plugs (**I know that certain sensors wires have different resistance/amps which adds to it) Trying to source each plug and pigtail and re-pinning seems like alot too. OR is there a better options that will save the headache. I also plan on buying the EBL4, which I am not clear on the effects of some of the bad wiring: IF, some of the sensors wires are bad coming from the PCM and I BUY a NEW "7730" EBL4 FLASH (keeping my old pcm) how would I add new/after market sensor wires ? I am tryin to learn and read alot of the "threads,stickies" but looking for options? (POCKET seems to be have Electrical down and his knowledge is impressive) ANY suggestions, help appreciated.

 

Parts for the connectors are available from Mouser www.mouser.com. Most of the connectors under the hood in these cars, in the ECM part that is, are Weatherpack. This week, the name of the Packard Electric division that makes them, is Aptiv. They're not cheeeeep at all; each connector actually consists of several parts, which you'll have to buy separately; but you can get as far as I know every single one. Each connector usually involves some pins (which are specific to wire gauge ranges), connector body, "terminal position assurance" which is like a hood thing that clips onto the back and keeps the terminals from pushing back out, and seals.

There's also somebody on ebay that sells pigtails, with the correct color wires, connector, etc.

Doesn't particularly matter what ECM you use, as far as "the effects of bad wiring"; pretty much the same things will happen to any of them.

As you repair wires, if you have to splice them, use rosin-core solder, extra separate rosin flux if you need it, and heatshrink. I'd recommend the marine type of heatshrink that has adhesive inside it.

Get the FSM for your car. It will tell you ALOT about what wires do what and go where. I'd recommend removing your existing harness from the car & motor, carefully and slowly, taking lots of pictures and notes; and labelling each connector, as you unplug it, with what it goes to. Then once you have it all laying out in front of you it will be MUCH easier to see what damage or deterioration needs repair.

As far as sensor wires go, there's no difference. They're all copper. Close to 0 ohms. As long as they're intact and don't have intermittent connections or faulty insulation allowing contamination or moisture or whatever, the wire makes almost no difference at all. SXL, GXL, & TXL are the most common automotive types nowadays; their insulation is VERY durable.

 

In regard to the Electrical-Connectors:

If you educate yourself on the Parts and Assembly procedures for the Electrical-Connectors...
Then purchase the Tooling...
It is far less expensive to build the Connectors yourself, than purchasing an assembled Pig-Tail.

For example:
A certain Pig-Tail may cost $65 when already assembled...
VS $8.37 in Parts to assemble the Electrical-Connector on your own.

However, this is only the situation after making the investment in Crimping Tools and Terminal Removal Tools...
as well as an investment in Time to be educated.