Engine SwapEverything about swapping an engine into your Third Gen.....be it V6, V8, LTX/LSX, crate engine, etc. Pictures, questions, answers, and work logs.
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any pictures of the plug you're using? since things were changed, there may be an issue with the wiring swap. only thing that comes to mind right off the bat. other than that, loose belt?
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1987 Trans Am, work in progress
2008 Pontiac G8
Retired: 1984 Camaro "ZF" 2.8L, 1989 Camaro RS
Customer Service Manager, 1A Auto Parts
Thanks for replying, sorry i have been crazy busy!
Here is a pic of the alternator used.
I have the 2 wires to the alternator the large red one, and the brown one.
I believe the red is the switch on, and the brown is the sensor.
I also have one going from the pos post on the back side of the alternator to the BATT.
i have noticed the third metal post on the top of the alternator-NOT sure what this is for AND the GRND post on the back side.
THIS alternator came off a carb engine from an ambulance.....TRYIN to use it to save $$$.
Your gauge reads the voltage across the entire electrical system. The heavy red wire needs 12v constant, while the brown is 12v IGN. It is spliced into the fan relay harness from the factory like that
Im unfamiliar with older alternators but the plug shown is not the same and may be wired differently. Compatible alts can be had for very cheap at any junkyard
that looks to be the old style gm alternator. take the first terminal closest to the batt lead and hook it to the batt lead. then make sure that the next terminal gets power with the key on. they also make a gm one wire that eliminates needing the exciter wires.
__________________ YOU MUST ALWAYS PUSH THE LIMITS-IF YOU NEVER FAIL YOU WILL NEVER SUCCEED--NO FEAR!
Got 12V all the time at the red, but if it gets 12V coming off the starter is it fine? or does it have to go from the batt post?
ALso, does not seem to get 12V ign key on from the brown, BUT it does read it? thought that was for the gauge? gauge reads, but no 12V key on???
one could go to the gauge. but. one can come from the starter or the battery. both have power at all times. mine are red and black. one needs to have power at all times. one should get power with the key.
__________________ YOU MUST ALWAYS PUSH THE LIMITS-IF YOU NEVER FAIL YOU WILL NEVER SUCCEED--NO FEAR!
the red wire goes to the starter and the brown the wire is coming from the firewall on the driver side this wire goes to your gauge cluster these two wires are togther in one plug. now I am not sure of the next part you may need to put in a rezistor on the brown wire. 78-90 ohm.
Hi ! I was reading your post and wondered if U could help me ?? I have an 88 GTA TPI 350 with digital dash, I'm swapping the engine harness with what is supposed to be a harness from exactly the same car. Problem is the old harness has 3 leads off the Alt. plug red/ tan/wht and a brown. The replacement harness has only a 2 terminal plug. Not knowing exactly where these wires go concerns me about the difference between the 2 harnesses. Can you enlighten me ??? Thanks !!
Hey !! Well after thinking about this I decided to take a closer look at the replacement harness and found out where the difference is,,,,I was not sold an 88 harness. Ya ! the experts were wrong,,again,,,the harness is from a later MAS car, it only has 8 injector plugs,,,,no cold start injector plug, so it looks like it's back to the vendor for the rite one. This happens way to much in my opinion, bad advice from another expert is why I need to replace the harness in the first place. So we know,, 3 wire alt. plug for 88 and 2 wire for later set-up. I guess I'll just consider this yet one more reason to investigate everything my self because the experts usually aren't. Well there we are,,,thanks for the quick response, I hope this saves someone else some time in the future. Sure is nice having access to this cite to mull stuff over with other 3rd gen owners. Take care and thanks again !!
