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Can anyone help me identify these wires and what I need to do with them? These wires are all part of the main engine harness coming through the firewall. The black wires are near where the brake booster mounts and the other wires are right behind the distributor. The setup is an 89 formula firebird TPI 305 with a manual transmission. It has been swapped to an 86 trans am. The engine obviously has not been cranked since being swapped. Any help would be greatly appreciated.

TPI Sierra

The first pic both are most definitely grounds, they had ring terminals on them and both have broken off.

Not sure about the second pic. The black/white is likely another ground but the tan wire I am not certain. It MIGHT go to the fuel pump and fuel pressure/oil pressure switch.

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The black wires were taped up inside the wire loom when I found them but I am not sure if they were supposed to be. Is it possible the wires behind the distributor could be for the speed sensor on the side of the transmission?

TPI Sierra

Surprised it ran at all if it did.

No on the VSS, they are purple and yellow.

I'm thinking they also may be grounds, I know I had a tan ground wire on my 1987 harness.

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No it hasn't ran since I swapped it into the other car. I haven't gotten that far yet, that's what I am trying to do, but I have to get all these wires figured out first. Another question though, I have a purple and yellow wire coming off the clutch pedal any ideas where they go?

bigal55

iTrader: (1)

Yellow wire comes from ignition switch and has power in "start" position. Purple wire goes to starter solenoid and powers the solenoid to engage the starter in "start" position. That is a clutch safety switch and does not allow the engine to crank unless the clutch is pushed in. HTH!

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bigal55 here are a couple of pics of my mess of wires where my pedals go. The pedals are not installed yet because they would be in the way but there is the pigtail coming off the clutch pedal, which is purple wire and yellow wire with a connector on the end. I traced the yellow wire from the ignition switch down into a relay?? Out of the relay there comes a green wire with white stripe, also there is a purple wire from the firewall that has been cut and was attached to the yellow wire. If I understood you correctly, I should hook the green and white wire to the yellow from the pedal and the purple to the purple, is that correct? Also, any pictures of your pedals along with wires and or vacuum lines going to them would be great.

bigal55

iTrader: (1)

Sounds as if someone installed an aftermarket theft deterrent device (the afore mentioned "relay"). Here is a circuit diagram for an 86 starter circuit (from Austinthirdgen.org). You should put the clutch safety switch wiring back to original (safety device) and clean up the wiring so it replicates the original. I don't have any pics of any vacuum lines but there are diagrams here on TGO. As for wiring diagrams, AustinThirdgen.org has just about any diagram you will need. HTH!

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OK so none of the wiring diagrams on austinthirdgen matched what color wires I have but I found a forum on here that did have an accurate diagram. The relay is the starter enable relay for the VATS. Apparently at some point someone had tried to bypass it by hacking the purple wire and attaching it to the yellow. I am going to fix it back to the way it is supposed to be, with purple going to the purple and the green and white going to the yellow. The VATS has been programmed out of my computer so I shouldn't have any problems even without the original key and switch.

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So I just wanted to say thanks to the two of you guys for the input. I got frustrated with all the jumbled up wires and ordered a factory service manual for my car...it turns out that all the wires under the hood that I had questions about are ground wires. Now I just need to extend them so that I can ground them where they go and maybe I can get this thing running soon

bigal55

iTrader: (1)

You're welcome, just glad I could help. Factory service manuals are great for situations such as this. 86 model year third gens didn't normally get VATS but being a TA it probably did have VATS. That's where the service manual comes in, it will have all the correct info and wiring diagrams. Good Luck, and get that thing running !