85HPP 3G alternator install

[gadget73]

Yes, unhook the battery cable before messing with stuff.

[1990LTD]

just ebayed a couple of these since I can't find big fuses fuckin' anywhere locally

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=390025192470

175A should cut it.


Could someone explain the importance/purpose of a fuse holder?

[1987cp]

Dang, you have to get those off of eBay? That ruins the whole convenience of being able to buy it at the corner parts store like I did .... also, it will make life very inconvenient if it does blow and you have to wait days to get a new one.

Like I mentioned before, with the Megafuse you don't actually need a fuse holder. It'd be nicer with a holder, but you can also just put one end of that style fuse over the solenoid stud and attach the other end to your charging cable with a small nut and bolt.

What sort of options do you have available at your local parts stores? I'd hesitate quite a bit before using a fuse I can't get locally, unless maybe you just buy a pile of them .... in which case you wouldn't be that much money ahead of running a fancy circuit-breaker system.

[1990LTD]

I bought a handful since getting one would defeat the purpose


Am gonna try more places locally but it isnt lookin good.

[91waggin]

Am not sure what you mean - I'm likely going to leave everything I can in the car. The fat charge wires will get snipped at the alternator end and the stator wire will as well. Stator and charge wire will get snipped on the regulator end. I don't care if leaving them in there will be messy, I don't have nearly enough confidence in my own abilities to fish out and delete wires through the engine bay.

Regarding this:

You are going to unhook the old black charge wires from the alternator, yes. However, on some cars, everything will go dead if you unhook the other side of the charge wire from the starter solenoid on the passenger fender. If you can get away with unhooking it and removing the entire wire from the harness, go for it. Just know that you might not be able to get away with it.

[1990LTD]

Regarding this:

You are going to unhook the old black charge wires from the alternator, yes. However, on some cars, everything will go dead if you unhook the other side of the charge wire from the starter solenoid on the passenger fender. If you can get away with unhooking it and removing the entire wire from the harness, go for it. Just know that you might not be able to get away with it.

I am fine with not getting away with it...I just want this damned alternator in the car The wire shall stay on ye olde solenoid, then.

[1987cp]

BTW, I remembered today (duh) that the headlights in stock configuration are not powered directly from the starter solenoid ... so, unless there's other junk getting its power from the charging harness (easy to check by tracing from the big plug - there should be 2 big black wires and one big yellow wire, and one tiny green wire going to the headlight plug and from there to the dash warning light), the old charging wires are the only thing going from the starter solenoid toward the front of the car.

I've actually been for the time being running my ignition power directly from the alternator's charging stud, but I need to check with the more experienced mangs about how good an idea that really is. I got my new 3G today, and after temporarily reconnecting it to the old ring terminal connected to the stock charge harness, I connected it instead to an old stock-style starter cable that happens to have just about the correct ends on it, in addition to being about 4 AWG and very nearly the correct length. I connected it to my good old 175A MegaFuse.

[1990LTD]

Got that little wiring harness in the mail today, and got the 175A fuses yesterday. Only missing puzzle piece of a fat charge cable...couldn't find any today but will look tomorrow.


I don't imagine there's much work involved in switching the pulley from the old 2G, eh?

Oh yeah, the guy that sells the wiring harness for the 3G upgrade includes a sheet with wiring diagrams just like the ones stickied here.

[1987cp]

Nope, not at all. An impact wrench makes it easy, but it's not critical. You can probably just use the belt to hold each pulley stationary as you turn the nut.

[1990LTD]

the 3g, she is installed! I could barely get it to drop below 14 even with all of the accessories on (rear defrogger, lights, dome, courtesy, radio, wipers, etc). I could get it down to 13.9 but there's no way I would have that much stuff running in a real-world situation.

[1990LTD]

also...seriously, thanks a lot for your help, everybody.

[85crownHPP]

Did you get that nice tingly feeling where you were done? I love that feeling...

[1990LTD]

No, I got a terrible fear because when I started it up, it sounded like a howling dog as it spun because the belt wasn't quite settled, but after giving it a little stick, all was well. Mechanic said it sounded like it just needed to work itself out since it (the 3g) probably hasn't seen active use in a while. Needed to "break in" for lack of a better term.. also, holy shit, that bolt on the bottom is l-o-n-g. I didn't think it was ever going to stop turning

[1990LTD]

Also: This should be inspirational to folks that didn't think they could do something like swap alternators...if an imbecile like myself can do it, anybody can! I can't believe I was so scared to do something so simple.

[1987cp]

I can't believe I was so scared to do something so simple.

Could be worse. Not all that long ago, I was afraid to take off my TFI distributor cap to see if there was moisture inside, becuase I thought it might mess with the timing!