I have a 84 which should have the voltage regulator in the alternator, right? I have 93 alt. which is a 100 amp but I do not see why I am getting 14.9 volts. By the way I have had high voltage on the other setups I have had in the car.... any help would be great.

 

found problem...... open short on the "S" termenal somewhere in the stock wiring..

 

Ok, so how did you find this open short? I just developed the same when I cleaned the engine. I figured I "introduced" a bad connection (i.e. corroded) with the chemicals I used or something. It seems to be ok until the engine warms up a bit - then "bam" spikes to 16+ volts. (Mine is a 85 GSL with the big 55A alternator)

M.

 

i have an 84 with a alternator from an 89 and it produces 14 volts constant with the internal voltage regulator. by the way will it harm anything if it continues to do so?

 

It is not right - so I must fix it. I suspect either voltage regulator - finding my Haynes manual to locate (believe external on 85 GSL - stock alternator). Was not a problem before cleaning the engine bay. I do not like the needle pegged on the dash. Going back down to get a meter reading.

 

Inconsistancy is the name of the game. Was running it again and the voltage was "normal" (14.48 V) - let it idle for about 5 min. whilst chasing a vacuum leak (not found yet) and the dash meter spiked again. Well the trusty volt meter is telling me 16.25 - 16.68 Volts! NTG! Do not want to cook my battery either (figured dumping this much voltage over a long period might make it "pop". Can not find my darn manual. Can anyone confirm or deny an external voltage regulator on a bone stock 85 GSL? Where might this be?

 

what i did was take the plug that goes to the alternater and checked to see if there was 12+ constant on one and then one the other wire 12+ only when the ign. is on.

 

yep..... that fixed it .... solid 14.03 volts

 

Definately changing when warmed up. Starts off 14.48 then after about 5 min. at idle (rough due to vacuum leak I think). Then spikes. When running all post read the same voltage - whether it is 14.48 or when it is spiked.

 

The batery voltage is 12.47 (between post). The voltage to the top of the plug is 12.27 and to the bottom of the plug 12.47. All test with the engine off (ignition in the on position).

 

Ok, trusty Haynes book tells me that voltage regulator on 80 internal - but does not say "1980 and up" going to hunt for VR and will report back findings.

 

It is normally found "on the left fender panel" it looks like the pict indicates right next to the clutch master cyl. on the firewall.

 

check it with the ign. off and make sure there is only 12v on one of the wires

 

Kevin, I get voltage between + of battery and either of the posts on the alternator. There is a check relay that (same color wires as alternator - same style 2 prong plug) is located by the clutch master. Cleaned the contacts - no avail. The alternator has IC Reg Built in - part number A5T30574. Noticed the alt. is rather warm if that helps any.

 

I think your alternator is bad...... take it off, then take it to autozone and they can test it for you.

 

Just got back from autozone - they tested it for 3-5 min. it all passes. I just bought a can of electical contact cleaner and sprayed the inside of the alternator as best as possible - letting it warm up now to see if it made a difference.

 

Ok so far. After "filling" the alternator with contact cleaner and blowing it out with presurized air I seem not to get this issue any more. Just took it for a spirited ride and then let it idle and it never got above 14.47. Put headlights and AC and full fan and did not notice much of any drop of voltage. Will give it a couple days then post back.

 

80 and up is internal regulator

 

i have to say negatory on the 80 and up being internal regulator my car is an 84 and has external. as far as i know all the 12a fb's have external regulators.

 

ARRRGG! My high voltage is back. Seems to be heat related - It happened this morning after about 7 min. at idle. Builder7, is the "Check Relay" the same as a voltage relay? It is quite confusing since my alternator is marked "IC Reg Built in" (mine is an 85 GSL).

Anybody have any ideas?