Project GatTagO

iTrader: (7)

I just looked on mine and its definitely number 3.

Andrew

mkoch1

iTrader: (1)

okay so I replaced my 98 alternator with part number a14vi39 /
10436674 best I can tell this is for a 01-02 corvette. Anybody know if the 98 alt and the 01-02 alt are wired the same? Looking at the below picture my 98 is wired like this.

#3 is hooked up to a resister (2- 1000 ohm 1/2 watt resistors in parallel) and switch 12 volts.

#2 is hooked directly to switched 12 volts.

I wired the 01-02 the same way but the l0 amp fuse that is on the line for #2 + #3 blew the first time I took the car out.

Mystic96

Will this be something that is required on all LS1 swaps?

Having the LS1 alternator work with my Mustang charging system is a big concern of mine.

Slow 346

iTrader: (33)

I have a friend that rebuilds starters and alts for a living. He only had to change my voltage regulator inside my 2000 alt to convert it to a true 1 wire set-up. I now only have the positive lead off of the back.....nothing to the regulator. If anyones local....I could get a price on this.....id say somewhere around 80.00 to do the conversion.

MrDude_1

iTrader: (4)

no reason for concern... they're both negitive ground, 12 volt systems.

the big stud on the back goes to a thick wire, running either directly to the battery, or to a power disribution block that the battery is also connected to.

one of the two inner terminals needs +12volts when the key is on(i forget what one, i'll look it up tomarrow)
that wire just turns the alternator on.

the alternator has to be turned on, to work. if it was just connected to 12v all the time, it would be a slow drain on the battery.

this means the alternator has two wires... the big power output wire, and the turn on wire.







one wire alternators have just the big power wire.
the advantage (if you can call it that) is that the ignorant masses (no offense to anyone here) can just hook up one wire and go.. very popular with SBC guys because sometimes the wires in the chassis setup dont match what they need for the alternator to work... so they dont worry about it, and get a one wire alternator.

one wire alternators work by having the alternator generate a voltage, once that voltage gets high enough, the regulator and everything kicks on... the LS1 revs high when you first start it up, so you probly wont see this prob, but on othere cars, you have to blip the throttle to get the alternator spinning fast enough to initally excite itself... THEN it starts working... but until then, its all battery.

i found the answer on here earlier, but the search feature sucks.. i'll look at my car tonight and tell ya what wire needs +12v ignition power to turn it on.

jimmyp

iTrader: (1)

i have a 98 ls1 and I replaced the alt with a new one labeled 98-02 f-body ls1 that I got off ebay. Its brand new and from a reputable seller. There was some talk of the 98s needing the resistor while the 99+ dont. How can I tell if I need it or not?
thanks

digitalsolo

iTrader: (24)

From what I've gathered, it's just confusingly worded in this thread. The actual F-Body alternator between 98 and 99+ is compatible. The difference is in the harness itself. On a 98 Harness you need to wire the alternator generator wire (red wire in the blue "230" plug under the dash) to a 470 ohm resistor, then to a +12V source. On a 99+ harness it is run to the PCM, so there is nothing to wire. Doesn't matter if you have a 98 or a 99+ as long as it's an F-Body alternator.

Hope that makes sense.

jimmyp

iTrader: (1)

cool thanks

GTA91

iTrader: (14)

I've got issues with my setup... '98 LS1 in my '91. It won't charge at all... it just has the one little red wire in the 4 wire pigtail. I need a 470ohm resistor and then 12v switched power behind it?? Sounds good, let me know if this is for sure!!

jdperk-86elco

Quote:
"Even the 99+ wires can be made to work with one wire and a resistor.
Just put a 470 Ohm resistor in line with pin B of the Alternator connector. Connect the other side of the wire to a 12V ignition source, and that's it.
So... 12V ign - 470 Ohm resistor - Pin B on the alternator connector."

He is correct it is one wire. One end connected to Pin B and the other end of the same wire to 12V, thus one wire. This isn't counting the main charge wire back to the battery.

The one wire is the field wire to get the alt to make power out the main charge wire to the battery.

GTA91

iTrader: (14)

I'm still having issues with mine... we messed around with it the other night and couldn't get the gage to show a charge at all. I took the alternator off and had it tested at 2 places... both said it was bad. Bought a new today, put it on tonight, put switched 12v power to that #3 terminal with or without the 470ohm resistor and still nothing. WTF is going on here? I took the new alternator back off and I'm going to have it checked out tomorrow. Can someone please tell me what to do?


*We were just using the brown wire in my TPI harness from my original TPI alternator (which has 12v with key on) and we had that connected to terminal #3. With or without a resistor made no difference. Did I maybe screw the alternator up without having the resistor in there? Is it ok to use this brown wire? It was the battery gage signal wire from the TPI harness if I'm not mistaken.


Thanks for any help!

MrDude_1

iTrader: (4)

exactly.

not being nitpicky, but outside of the LS1 world, a ONE wire alternator, refers to a SELF exciting alternator... the ONLY wire is the big main one going back to the battery. there is only that one.


thats just something thats been bugging me about this thread since it started..


anyhoo, GTA91, bypass the TPI harness wire for now, and try running one right off the battery, just as a test.

RFERG43

I've done the LS1/RX7 swap. The engine is a tight fit but it does go in. Once in there is a good bit of room on each side but little between the heads and firewall. You need bend the heater hose connections up and it is much easier to put the hoses on before installing the engine. A few licks on the upper middle of the firewall will make it easier to get to the stuff on the back of the intake. The lip on the firewall needs to be cut off around the heater hoses. A look at the V8RX7 web site is very helpful.

Speartech

iTrader: (14)

We are talking about position "B" on the 4 wire connector. The brown wire from you TPI harness should be fine as long as it isn't damaged. Otherwise you use a wire from a switched ignition source WITH a resistor inline. Not using the resistor can instantly damage the voltage regulator and ruin your new alternator!

I've posted and posted about this on here; they are NOT made to have 12 volts applied to them. Some may not die instanly but some will.

We have lots of 1K resistor around here, so I always put two in parallel for 500 ohms.

Don't hook them up without the resistor unless you are using the 99 and newer LS1 harness. On these the PCM has the equivalent of the resistor installed internally. With these harnesses you go straight from the PCM (RED 15) to position "B" on the alternator plug.

Of course, we take care of this with ALL Speartech harnesses, new or reworked!

GTA91

iTrader: (14)

John THANK YOU VERY MUCH for chiming in... I was hoping you would. I would've emailed you but I know you're busy. I just took back my new alternator (1 day old) and I have to stop at another place and get another new one. We had the brown wire from my TPI harness hooked directly up to terminal "B" on my original alternator... so I'm sure we fried that. Mistake #1. Then I put the new alternator on last night and my dumbass didn't put the resistor in, fired it up, and apparently fried that one too. Mistake #2. I will get another new one tonight, solder a 470ohm resistor in line on the brown wire and see if that works. If it doesn't, then I'm setting the car on fire. LOL


Thanks!

GTA91

iTrader: (14)

One last question... does that 470 ohm resistor need to be a certain wattage? Will a 470ohm 1/2 watt one work or does it need to be 2 watts or something???


Thanks!
-Jeremy

Speartech

iTrader: (14)

Yes, a 1/2 watt is ok.

GTA91

iTrader: (14)

Thanks! Got it working... 14 volts or so at idle. Only problem is that when I rev it up slowly... at about 3k the voltage on the gage will start dropping and going down below 13v. WTF?!?! If I just rev really hard/fast it will do the same thing once it gets high up in the rpm's. I do have an ASP crank pulley on it but stock alternator pulley. Would this in anyway have something to do with it? What could be going on? I guess I need to go drive it some and see what it does but it concerns me now.

Thanks for any help!