ok so picked up a 91 rs with a 305 for free.. the trick was all i had to do was get it runnin. My room mate owns Motor tec..( Import shop) so i thought you know no biggie. got it to the shop tested the alt bat and there were ok. then we tested the ing coil and it had no continueite.(sorry bad spellin) so we replaced it and it ran fine for bout an hour. then it died. so we got it back in the shop.. we used a volt meter to check the alt and bat. the alt was readin 10.8 so i returned it for a nother one. went back to the shop put the new one on and it read 12.8 an the batt was 12.5/ so we thought we just had a little power drain some were. we let in run for bout 20 mins and it ran beautiful. my guy took it out for a spin around the block and it started dying out on him. soon as he pulled it in the bay it died. an i mean the batt was completely dead...1volt dead. lol. but we cant seem to figure it out. why won't the alt charge. what would make it do that. please if any one has any ideas please let me know. eathier repost her or my email is wicked_hatch@yahoo.com or if you have aim..b16eg. please i need to get this fixed. thank you for any and all your help.

 

There's a fuse in the charging circuit that makes no sense how it's labled, but it's in the I/P fuse block and it's labled "fan" Without it, the alternator won't have the proper field winding voltage, and won't charge nearly enough. There are also a couple of fusible links near the battery, and I know at least one of these is alternator related. Check those for continuity as well. Otherwise, Get the alt bench tested, they're easy to remove anyway. If it's a good part, you almost certainly have a bad wire or fuse somewhere.

 

ok so i checked the fuse block an there wasn't even a fuse in the fan spot... we put a new fuse in there and it didn't even make a difference at all... the fan on the car runs all the time as if it were bypassed.. could that have some thin to do with? is there anywhere else i should check..

 

As Flufy stated there are fuseable links and one is to the alt for a voltage sensing signal. Near the battery or off the starter. Dont just look at them but lightly pull because sometimes the wire corrodes or burns inside the big piece of plastic and you wont see it.

 

well the link inbetween the bat an the alt isn't there it's just a regular wire and the one that go's to the fan area is still good with checked it with a voltage light. but the one near the starter hasn't been checked. were bout to do that now. anythin else you guys can think of?

 

I GOT A 92 RS PRETTY MUCH WITH THE SAME PROBLEM. CHECK THE POSITIVE TERMINAL ON YOUR BATTERY IT SHOULD HAVE THE 4 GAUGE THAT GOES TO STARTER THEN IT HAS AN 8 GAUGE THAT GOES TO A LIL BLOCK ON THE SIDE OF THE RADIATOR SUPPORT BRACKET CHECK THAT OUT. ITS LIKE A DISTRIBUTION BLOCK. ALSO THERE IS A FUSE THATS IN FRONT OF THE BATTERY ON THE PASSENGER FENDER YOU MAY WANT TO CHECK THAT OUT. HOPE THAT HELPS.

 

That inline fuse goes to the fuel pump, and has no link to the starting/charging system at all. Since the car starts and fires, the fuse is clearly good, as it would get no fuel otherwise.

 

That's pretty strange. You may have a short to power somewhere in the cooling system, then. When I last had charging issues in my 91, that fuse was the culprit. I went for a week trying to figure out why all the wires were good, the alt bench tested for 14.5 volts at 110 amps, and it even had a proper ripple pattern on the bench, but the damn thing still wouldn't charge my battery. Got a hold of the Chiltons, and I found a fuse labled fan on the charging circuit, it was blown, swapped it out, and it worked fine.

 

we checked all the fusible links and fuses that would have anything to do with the charging system even indirectly and they all checked out fine rechecked all the wiring AGAIN and still had good connections etc. but the damn thing still wont charge at all.
the voltmeter looks like a stopwatch when u start the car....(a volt a sec approx)

 

here is a good one i have a 89 that the battery would go dead but it would take some time -i replace att --battery 5 different time with a new one--then i had a tech tell me my starter was draining my battery so i check the wires clean and the battery went dead again then one cold morning my starter quit i replace the starter and since then no problems with battery drain-the starter work good up until it died--bench test ur starter