Charging System Woes

[IronButt II]

Hi all...

Hope somebody can shed a little light on this problem. I picked up an 87 325 a few weeks ago as a project car. It had been sitting for about a year... but had apparently been running fine prior to being parked.

I've gone through and changed all the fluids, replaced the battery, and taken care of the minor problems that caused the previous owner to park it... (e.g. shifter bushings, broken front swaybar mounts, et al) The car now starts and seems to run fairly well... but I'm not getting the voltage at the battery I should be getting when it's running.

I've got 12.5 when it's off... 12.3 when it's on... 11.9 if I turn on the headlights. I pulled the alternator and took it down to the parts store to have it bench tested. Tested fine. Went through all the fuses under the hood... cleaned the contacts, continuity tested... all good. All the connections on the alternator, battery, starter are all clean and tight. No current leakage from the battery with everything off.

What am I missing? Relays?

There's about 8 relays in the fuse box, and a gang of three more just in front of the fuse box. I've cleaned all the contacts, but no luck. I really don't know if any of these are even within in the scope of the charging system circuitry. There's one in particular in the gang of three... metal housing, 5 or 6 leads I believe... looks like a couple of fairly beefy wires feeding into the plug. Could that be my problem?

I do have a manual, but unfortunately... it's a Haynes, and it seems to be completely worthless on this subject.

A couple other things to note... somebody obviously tried to work on this thing at some point between the time it was parked, and the time I got it. The first time I went to connect the battery (it was disconnected when I got it), the starter motor began to spin... with the key off. Found out the cables on the starter were transposed. Neat!

The other thing I've noticed is that, when starting the car... the starter motor has kept spinning... even after the key is released back to the "RUN" position. This has happened twice... out of 10 or so starts.

Wondering if the ignition switch could be the answer to both problems? Perhaps that's too optimistic...

Any help would be greatly appreciated.
Thanks!

[323I Junkie]

VEry possibly, the ognition switch supplies power to the alternator field, which alows it to function. check power at the field on the alternator, of there is noe with the key on, if you dont have a diagram, start tracing back

[IronButt II]

Thanks, I'll give that a try this evening.

[323I Junkie]

Thanks, I'll give that a try this evening.

I beleive that the alternator is even marked field or "F"

[Titansilber330]

I know this is an old thread but I have a very similar problem what was the fault for your car.

[thejlevie]

I never can remember which years it applies to, but older cars must have a good bulb for the alternator warning light or the alternator won't work. In later production a resistor was included in the circuit to bypass a burned out bulb.

[Titansilber330]

My bulb works

[thejlevie]

Then that's not it. Check to see if there's Field voltage at the alternator with the engine idling. If that's present check the voltage at the alternator output lug.

[johnnyscott]

Another thing you should definitely check is the inline fuse that's found about 8 inches up the second wire leading from the positive lead of your battery. It's a fusable link that will be "shrink wrapped". If that fuse is corroded at all, it really can cause all kinds of electrical issues... Then again, it could simply be your ignition...

[Titansilber330]

Another thing you should definitely check is the inline fuse that's found about 8 inches up the second wire leading from the positive lead of your battery. It's a fusable link that will be "shrink wrapped". If that fuse is corroded at all, it really can cause all kinds of electrical issues... Then again, it could simply be your ignition...

The fuse looks ok how do I check the ignition?
by the way its an e36