Hey guys,
I am new here and I just had to ask a couple questions. I recently did my alternator on my 1997 Eclipse GST because the old one was absolutely cooked, and replaced it with a 90 amp one from WAI. Problem now is that the car will sometimes not crank and the battery will get drained relatively quick. Any help would be appreciated!

Start with checking the battery terminals for good connection. Make sure the alternator belt is not loose and tensioned properly. Make sure the plug is connected . Make sure the output wire for the terminal is not loose either. Measure, the alternator voltage output with the car running. Measure amperage that it puts up, unloaded and under load. Do a parasitic draw test, if your battery gets drained overnight or fairly quickly . Some aftermarket alternator make have bad rectifiers from the factory. Those would be basic check points.

When you check battery terminals, do a voltage drop test also. And when I said rectifiers in some alternators are bad from factory, I ment they can cause a draw on your battery. Just in case I didn't sound clear. Good luck

There are some simple tests you can do with a multimeter to check for alternator leakage current. I have a similar situation, I replaced mine in June, but with an older compatible OEM alternator. I took it to O'Reilly's after cleaning it up a bit and got a leakage current value of 85mA (outside specs). Installed it anyways and I've been getting different readings since installation... So not completely sure what's going on. But I'm sure it's the biggest current drain with the engine off.
If you just do a search for "alternator leakage multimeter" or something similar I'm sure you'll find the tests.
I'll probably start my own thread on this issue since I haven't found a good solution.... but thought I'd pass on this info.
What I did in my case was:
- Disconnect the negative battery cable from the battery terminal post.
- Measure the current across the disconnected cable and battery terminal post
- Disconnect the positive B+ wire from the alternator
- Take another current reading at the battery terminal post.
Huge difference the first time I did this.

Thanks for all the help so far! I tried to use my friends multimeter but his was not working so im going to borrow one from work. In the meantime i am going to check the fuses and fuse box too see if theres anything loose/corrosion. Im thinking i should also check the grounds on the car as well, anybody have any diagrams for them? Again thanks so far!

xiprometheus said:

Thanks for all the help so far! I tried to use my friends multimeter but his was not working so im going to borrow one from work. In the meantime i am going to check the fuses and fuse box too see if theres anything loose/corrosion. Im thinking i should also check the grounds on the car as well, anybody have any diagrams for them? Again thanks so far!

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Multimeter is something you should own. KLEIN products are decent and wont break the bank.