I have run into some confusion trying to wire up my alternator and starter in my Lt1 swap (94 vette into 89 V6). A lot of the information I found through searching is contradictory or vague.
If members could post their setups it would be most appreciated.

questions:

1. Do any other wires from the original car's wiring harness need to go to the starter other than the purple cranking wire? On my other firebird (87 5.0) 2 red wires run to the starter's main post from the fuse box under the steering wheel--do I need the same setup for my Lt1?

2. There are 4 wires coming from my alternator: large red wire from rear post, smaller red wire from a connector, and 2 small brown wires from the same connector. Which goes to battery, which to starter, and where does the second brown wire go ? (I know one of the brown wires goes to its mate in the original car's harness)

3. Does the power wire from battery to alternator need to run through a distribution post, or can the wire be run straight from the battery to the alternator?

The rest of the motor is wired with a Painless harness if that matters. Hope this makes sense, and thanks for your help in advance!

 

I'll try and help where I can...the two small brown wires coming from the back of the alternator can be tied together and connected to the brown wire coming from the cars original harness into the car(drivers side next to brake booster). The large red wire from the alternator can be wired directly to the battery. That is how mine has been for about 1800 miles and no problems at all. I bought a generic distribution terminal and wired the the two red wires from the same harness(drivers side) that need 12v all the time along with another wire running from the battery for constant 12v. I also tied the smaller red wire from the alternator here. Also, if I'm not mistaken, there are two red wires that to go to the starter from the Painless harness. These wires perform the same function as the ones you mentioned on your other Firebird(power for the ECM), but for the Lt1 they are switched power for the PCM. I'm sorry if this doesn't make sense....it's been a very long day and please feel free to ask me to clarify anything that doesn't sound right to you.

 

Thank you very much for your reply, your posts have helped me a lot during this swap. The only thing I had trouble with was finding the brown wire from the original car's harness. I checked on the driver's side by the brake booster (and several other places), but found nothing. I don't know if it is different because it is a V6 car, I will have to check my manuals to see if I can find that wire or its equivilent next time I get a chance to work on my car. Thanks again though, you cleared everything up for me.

 

Great....I'm glad some of it came out right...like I said, that day I was very tired and couldn't think straight. I take it it should be running soon then?

 

I hope it will be running soon! It will still be a while before I can drive it--it has to go to the welder for the exhaust and roll cage, then the windshield guy, and then be inspected.

I also still have to figure out how to mount the torque arm to the Vette 4l60E which has no provision for it. In retrospect it would have been much simpler to go with an F-body trans, I already had to build a custom bracket just to mount the trans to the crossmember. Or I suppose I could just go all out and install a 4 link.

Are you really planning an LS1 swap sometime in the future? I remember reading that in one of your posts. Again, thanks for your help!

 

Yes....thats the plan so far. I always like to have a project car laying around(or money pit if thats a better term ). I plan on taking much more time with that one as with the Lt1 swap, I was in a such a hurry to get it running that I was always running out of money.