I have an 88 Pontiac GTA, alt tested bad on and off car at 4 different stores. But each store shows an alt with an external fan and the bolt hook up points are different. Mine has the fans inside and has cover on back and has 6 rib belt pulley. the bolts are star type. No stamp anywhere to be found but there is a #, either 188 or 881 depends how you hold it. It has a 4 wire round pin connector and a 1 wire battery connection. The front shows Delphi Automotive Systems. It looks like a CS130HD type alt. I can send photo of it if someone can help me with the right part#. Thank you

 

The internal fans and Delphi markings are a pretty good indicator it's a later model alternator someone swapped in. Delphi wasn't even a twinkle in the General's eye in 1988. While it's possible that Delphi has since manufactured or remanufactured stock style alternators, I'd expect a sticker with Delphi's name, not a cast-in logo.

Your best bet would be to hit Google and start looking at GM alternators until you find one that looks about right. There are plenty of websites that detail the mounting ear positions, bolt spacings, etc since it's popular to swap a later model alternator into an earlier car.

Of course you could always swap back to stock...

 

Drew,, ok so if I would buy OEM alt, would the fan be on the outside and wouldn't that skew the belt since it seems that the OEM is wider than what I have right now? Yep, there is no sticker to be found. I am searching for it like you mentioned but have not found a direct match yet. Hey and thanks for your quick answer. Appreciate that Thanks

 

If you can find a way to fit a CS-144 alternator in there, that unit is kick-a$$.
http://sethirdgen.org/cs144.htm

 

that is a lot of $$$$$ and a lots of amps. What would all those extra amps for the car? I have no added accessories as such. Thanks

 

Hard to say, since it's customized. Assuming... But I wouldn't want to assume.

You might try checking the Yellow Pages for a local starter/alternator rebuild shop. They aren't too terribly common anymore, but if you can find one, take the alternator you have to them, and they'll probably be able to tell you what it is without much trouble. For that matter they can probably rebuild it for you, and save you a lot of trouble.

 

Being a one wire unit, it is definitely aftermarket. The type is like one from a 98 Camaro/Gm, but modified for one wire. There is a google page to make a LS1 alternator one wire, so that is how they must have done it.

 

Post a picture. Someone here can surely identify it.

 

 

That is exactly what it looks like. Mine did not have any stamp or part # on it. So unable to find one locally and seemed that I needed it ASAP, I went ahead and bought an OEM. Had to modify pigtail but it works great. Thank you all for your answer. You all are terrific and awesome website.

 

Glad you are running again.