Afternoon gang, Let me riddle you with a few charging questions to see if I’m doing this right. It’s on a custom car and here’s the parts I’m using: Engine: Olds 215 Harness: Speedway 12 circuit (GM based) Alternator: Powermaster 90A T-Bird style Gauges: Voltmeter (no idiot light) The alternator connections are: GND, L-Term (light), and BAT charge post. The wires on the harness are: ALT PWR (red), ALT EXC (white), IGN SW (purple), SOLENOID PWR (Red) Connections on the Starter at: RED and BLK in a connector on the solenoid on top (BLK has a diode installed which is for the MG conversion guys, not used in my application), BAT post The issue I’m seeing is mixing of Ford and GM wiring coupled with an internally regulated aftermarket alternator. It’s not really an issue, I just want to make sure my thinking is right on hooking the wires up. Let’s start at the alternator. 1. Alternator wiring should be ALT PWR (red) to the charge post on the alternator. Another thinner wire needs to run here (as per instructions) to either the BAT post on the starter solenoid or directly back to the battery (+). This is a byp*** wire required by the instructions for a 90A alternator. The ALT EXC (white) should go to the L-TERM (light). QUESTION: Do I need to run a larger 6ga cable from the charge lug on the alternator to either the BAT term on the starter solenoid or directly to the (+) post on the battery to provide a larger wire for battery charging? Since I don’t have a lamp, that ALT EXC wire will still function the same (providing the exciter charge needed to charge at idle) and as long as it’s a switched 12V and not a constant 12V the car will shut off when the key is off. 2. Starter Wiring: The large red SOLENOID POWER goes to the BAT terminal on the solenoid and the IGN SW (purple) will connect to the RED wire of the connector. That purple sends the signal to close the solenoid and engage the starter. I’m thinking the way I’ve described it should make the system charge at idle, provide the byp*** needed for the higher AMP as suggested by the instructions for the Powermaster Alternator, and most importantly, shut down when the key is turned on. Am I thinking correctly? Thanks guys! Cheers Dave
I've done wiring with a few different harness suppliers (Speedway NOT being one of them). I've read your description on the wiring process you have written 3 times, and its still not clear to me. That does not mean you are wrong, it just means I can't follow along. All of the harnesses I've used were pretty specific about which wires connected to which alternator you were using, and pretty specific as to which starter you are using. When it comes to a wiring harness question, my advice is to call the harness builder hot line and ask them.
It always helps to tell us what exact kit you have, plus the part number on the alternator. Is this the 3 G style or ?? I hate working on any Ford that was new enough to come with an alternator because there too damned many either's, or's and iff's with the ******** things. You spend more time figuring out what you have than fixing it. A quick search brings up a batch of alternators for Ford ALL saying that they fit T bird. Powermaster Alternators & Generators for Ford Thunderbird for sale | eBay I tracked down one 12 circuit speedway kit and the instructionds pfd 91064017_2021.pdf (speedwaymotors.com) ***umes that who ever is installing it knows a lot about electrical circuits. Basically the red wire goes here, the blue wire goes there and the green wire goes to that other thing. Only the very basics for GM generator, external and internal regulator alternators.
What is the part number on the alternator? I'm not following your descriptions of the by-p*** wire to the battery and power being connected to the L terminal.
I'm thinking how the wire from the Bat post on the alternator is routed. "Byp*** " would be the most direct route to battery rather than going to a junction block that a wire from the battery and feeds to the fuse block, switch and other circuits .
The instructions with my Kwik Wire kit were excellent.. the Speedway ones... not so good. You are almost better off scouring the internets for help, diagrams you can understand. Worse case, get an alternator that plays well with the harness kit. I tend to make up cave sketches of what I have, fill in the harness (paint by numbers...) tags until I have no wires leftover and everything is hooked up.
Thanks for the replies, fellas. The Speedway kit is is # 91064017 and is the 12 circuit Micro kit. That’s the instructions you posted. Good find! It’s not overly detailed on instructions, but it wires much like the rest and I’ve done this before but this is a little confusing. It’s not overly clear since the Olds/Buick starter only has a stud for the battery and a single red wire for the solenoid power to connect to (purple). There’s no S or I like the GM or Ford. The diagram only shows a generic starter and wires going to it. Not terminal specific. The question arises that if the purple wire sends the 12v to engage the solenoid, what’s that red wire that says “Solenoid” for? In this case, it seems it may be an extra wire I don’t need. The byp*** wire is in the instructions to use if running a 90a alternator which is what mine is. That I don’t really understand either since it seems it’s just running in a parallel to the red 6ga that would run to the battery positive or starter lug. There is a Lamp terminal on my Powermaster Alternator, part number 81522-2 which is where I was going to hook the Alternator Excite wire. I do not have a lamp on the dash though. The instructions on the Alternator do say that this terminal does not affect charging. So maybe it’s there to provide functionality to the light on the dash, but not needed (basically it being a 1-wire but it’s not advertised as such.). Hopefully that clears a few questions on my descriptions. This will be about the 6th car I’ve wired up using an aftermarket harness but first Speedway kit like this. Never had issues before but it also wasn’t using different parts other than stock. They were straight forward installations, so this is why I’m asking a few questions to make sure my thinking is correct. Charging circuit is the only major lingering question. The rest of the kit is pretty simple. I’ll give Speedway a call later today, and possibly Powermaster too if I don’t get the answers I need from Speedway. I might be overthinking this and including wires maybe I don’t need to use. I’ll keep you guys posted! dave
Ok guys, an update and solution. I appreciate all the feedback on this and the help. I called Speedway and Powermaster. Alex at Powermaster was beyond helpful. So the solution: 1. Alternator wiring. The alternator I have only has the light (lamp) terminal to make the original warning light function. It doesn’t need the Alt Excitor Wire (white) to charge in any capacity. So in essence, this is a 1-wire alternator only requiring a charge cable from the rear stud on the alternator to the positive side of the battery. The ground terminal is there, and he recommended hooking to the same spot as the battery negative cable to create a good charge circuit and ground. I could run that cable to the starter lug as well and then another cable to the battery positive if I wanted. Either way, but he recommended just going right to the battery. That byp*** wire that the kit requires is only needed to carry more of the load so the smaller gauge wire (Alt Power - Red) doesn’t overheat. That wire in question (Alt Power - Red) is the one that Speedway shows running to the back of the alternator charging post which supply’s the power to the fusebox. Alex said to just run the red Alt Power cable to the battery positive. that completes the charge circuit. 2. Starter solenoid wiring. The Purple solenoid wire is looped with Red solenoid power wire. The red is hooked to the battery post on the starter and loops back to the ignition switch. When the key is in start, power is sent to the purple wire to engage the solenoid which comes from the red on the starter solenoid battery post I just mentioned. I will be using a starter ****on in this case, so pressing the start ****on will send the 12v to the solenoid though the purple wire which will be p***ing through a clutch/NSS. So no byp*** wire needed, no Alt Excitor wire needed. I figured I’d update the thread after I talked and got the answers I needed and hopefully this may helps others. I’ll crank the car next week and keep you all updated! cheers Dave
Thank you for the follow up. I'm also thankful that you went to the parts source to get your answers. I'm sure its going to help the next guy that stumbles across this same problem.
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