Joe Ricard

So I read all the past posts and all the tech posts on Greg Nichols site. I had the FLAPS test alt and it seems to be OK. made 65 amps no faults. So what is wrong? I think it is the excitation voltage through the resistor which is in parallel to the alt light. No problem

Except where is it? Dash alt light stays on. I traced the blue wire through the diagram from the alt across the page and back no resistor. But I guess it wasn't drawn in.

As a side note the oil level light also goes on which happend at the same time. oil level is good. wiggled the wire it fell off. RELATED????

User 4221

Joe,

Check the harness that runs from the jump start terminal, across the engine and down to the alternator.

I had the same issue and found the wires inside the harness had corroded and begun to disintegrate. This was giving me a no-charge situation and low-oil warning.

HTH,
Scott

Joe Ricard

Hey great idea. I needed something to occupy my weekend. Snaking new wire through a harness. I guess 26 years is a lot to ask from wiring.

78 faded silver 5 speed.
With new steering rack!!!

Joe Ricard

Ok spent the morning replacing wires from the terminal block to the Altenator, oil level sensor and both wires to the oil pressure sender. didn't replace the large red wire to the jump start post it looked pretty good. measure very low resistance terminal to terminal.

Makes me wonder about the test at the auto parts store. Alt made 65 amps. Should be OK right?
So I am going into the next leg of the excitation wire through the resistor (if I can find it) and the alt light.

Joe Ricard

12V at battery 12 V at jump start lug When I start car it drops to 9 while cranking and maintains 11.8 or so while running.

The blue wire on the alt 0 volts key off 1.6 v key on when car is running 5.3V. Alt light stays on.

GlenL

The alt light should go off indicating that the alternator is powering itself. The light is part of the "exciter" circuit which provides power to the windings. Once the alternator starts turning, the regulator supplies power to the windings to generate the right amount of power. At that point the exciter is turned off. That's how the regulator works; it powers the windings to keep the system voltage at about 13.5V.

I think that the parts store didn't know what they were doing. You need an alternator, or at least a regulator.

Bill 86.5 928s

Joe...I've had problems with my Alt as well. I ended up replacing the volt reg and brush assembly. I found that the armature contacts the ones where the brushes make contact I think it might be called the stator, something like that, was quite scored and terribly corroded by something. I cleaned the copper contact with a fine emery paper and so far things have held together. Other than the fact that my battery packed it in the alt seems to be working. I get a 14 volt reading on the guage and am reading 14.5 at the battery. Goodluck....Bill

Joe Ricard

I agree, Need Altenator. or get this one fixed. Have a local shop here in town that has very good reputation for rebuilding. I did the tests that Jim spelled out on the Grg Nichols site. Well at the very least I got new wires in the harness from connection block to Alt and oil sensors. They were pretty nasty, corrosion the entire length of the conductor.

Yes Bill Stator = stationary Rotor/armature = spinning part. Brushes transfer power from rotating pieces to the wires going out of the alt. Motor do this backwards.

Still want to know where that resistor is living!!!

GlenL

The exciter circuit resistor is mounted to the back of the instrument cluster. It is tied to the screws which carry the power to the alternator warning light.

Joe Ricard

Thanks Glen, I may decide to dive in there. However I am pretty sure that the tests I did indicate problem is within the ALT.

Joe Ricard

OK so the guy at the automotive electric fix it place said I had a bad rectifier. should be done today $90.00

Just pay the nice man and shut up

John Struthers

As Glen suggests, the exciter is located at the back of the pod,
upper right side as I recall.
Should be a little pill shaped critter with the leads out of either end held to pod by easily reached screws. You know...screwdriver technology...
Some folks have posted that they either went to a stiffer resistance version available from 928 INTL and possibly other Big 3 suppliers and Radio Shack as well. I have flicks of the darn thing but can't seem to load to the renn site.
PM your E-mail and I'll send you what I have.
If Scott is the same Scott I met at the Third Coast get-together he might still have digitals of his front/engine bundle rewire. I believe he was looking at the front jump point or mystery green wire when he discovered that lovely crunchy sensation in the bundle -something to keep in mind-.
Oddly, I once mentioned high 13's to high 14 voltage readings and was mildly rebuked by a Guru. I went out and bought a new digital AND a analog voltage tester/meter and the readings remained the same.
High voltage-engine off, high voltage-engine running at the battery.
So this post/threads have made me feel a little less dull.

Joe Ricard

Charging fine now smack in the middle of the gauge. Needed a new rectifier. 85 bucks next day turn around. 15 minutes to put Alt in when I got home. Man that damn thing is heavy pedaling a bike up hill. only 89 degrees 85% humidity.

Bill 86.5 928s

Way to go Joe....Not to mention holding that damned alternator up high enough to get the top bolt started ....lol... feels good to see that needle there right?....good-luck ....Bill

User 4221

You have hills in Mississippi?


Glad to see, in the end, it was an easy fix.