93 park avenue charging trouble

[cityredneck1976]

i have a 1993 park avenue n/a with 254k miles. i'v got one problem that is bugging the hell out of me and i'm not sure what else to check.

when the car is idling at a stoplight or whatnot the voltage gauge drops down to 10 volts. when i drive away it slowly goes back up to 13 volts.

so far i have done:

new alternator from autozone (they tested it 7 times and it is good)
new battery
new wire from battery to fuse relay panel on firewall
new wire from battery to starter
new ground wire from battery to body
new ground wire from body to engine
new charging wire from alternator to battery
new relay for the charging system per the schematics (haynes)
new bolts for the side post battery for the wires
i'v tested the plug from the alternator with a test light and with the key on/engine off the test light lights up per the haynes manual
also had autozone put their tester on it, when the car is idling the tester says there is no charge.

i'm at my wits end trying to figure this thing out.

and the only other issue i would like to figure out if i could would be the lamp monitor thing. it says all the bulbs are out, even though i verified they are all good and working. sometime the lamp monitor with flicker and starts flashing when i'm driving down the road. i have 'reset' the lamp monitor per the owners manual after replacing some burnt out bulbs upon getting the car.

i like this site and have a feeling ill be wasting much time on this board.

thanks
rex

[dreager]

The battery connections have been and are a constant cause of flickering and electrical problems with these cars as witnessed in other posts. Clean the entire area,apply dielectric grease and REALLY tighten the bolts.

Failing all this call HOTZ the moderator, he da man.

[cityredneck1976]

also when the car is idling i can disconnect the battery and the car dies. if i'm not mistaken the car should stay running with just the alternator. correct?

there is no corrosion at all on any of the terminals.

when i can afford it i will be putting in another new battery that has both side and top post terminals.

[Scrapper]

when you took battery wire off and it dies then there a broken down wire to the alt. because it should run with cable off. my mom and dads got a 91 and a 93. i'm sure you got a 3800 in it or 3.8 witch is same thing..but yes it's not charging like i say there a wire broken down somewhere.. you might even see iff ground wire to your starter broken down..good luck scrapper1..

[HotZ28]

Originally Posted by cityredneck1976

also when the car is idling i can disconnect the battery and the car dies. if i'm not mistaken the car should stay running with just the alternator. correct?

I know that you bought a new alternator from AZ and you have repeatedly had it tested for output, however, did they test the regulator for the ability to control voltage? Of course, since you bought it at AZ, it is in their best interest to find nothing wrong with it! Take it to Advanced or O’Reilly, for further testing. Be sure they test the regulator. If you get a good test from Advanced or O’Reilly, you then need to look at a vehicle specific wiring schematic to see how the alternator monitors battery voltage on your 93-PA. Buick used several methods during the early to mid 90’s. Some used the BCM to monitor voltage, while others used the PCM and some simply monitor voltage direct from the battery cable to the alternator. This is important information to have, because you must know what “excites” the regulator to allow the alternator to charge. I do know that the 94-95 PA used the PCM, but I am not sure on the 93.

Some people still seem to think that you can test an alternator by disconnecting the battery to see if the alternator can produce enough current to keep the engine running. This is an old myth that dates back to the days of generators with external regulators. The CS-series alternator regulators are mounted internally and are basically an electronic computer chip. Disconnecting the battery cable is not a practical way to test for output! If you do this, you may destroy the regulator computer chip. Disconnecting the battery will subject the voltage regulator (and computer) to significant voltage spikes, which in turn, may cause an otherwise working alternator to fail. Even if there were no damaging spikes, this test would not indicate whether the alternator was good, because the engine will easily run with a weak or failing alternator. Remember; always disconnect the battery before servicing, and NEVER remove the battery cable while the engine is running.

A simple DIY test you can use to see if your alternator is producing current. Turn on your headlights when parked and the engine idling with the headlights shining on a wall (at night). Notice how bright they are. Then turn the engine off. The lights should get dimmer when you turn the engine off. If the lights get brighter when you kill the engine, the alternator was not charging sufficiently. When doing this test, the lights should be the only load (turn the stereo, a/c and other accessories off). With a heavy load, an otherwise good alternator may not be able to produce sufficient amounts of current at idle.

[Jrs3800]

I agree with HotZ28....

The wiring schematics for the 93 Park show that its an ignition switched circuit... But the Voltage should come up smoothly when you start the car... On most of these I have seen the Voltage will hang for a second or two then come up to 13-14v...

Being that the Alt can produce Voltage, I'd have to say its receiving voltage from the Pink/Black Wire from the alternator, if it didn't it would not produce any voltage at all..

With the amount of electronics on these cars, Never ever for any reason remove the battery cable while the car is running.... You could do a lot of damage...

[HotZ28]

Originally Posted by cityredneck1976

also had autozone put their tester on it, when the car is idling the tester says there is no charge.

Sorry, but I must have missed the comment above in your first post. If this is correct, you are not getting voltage to the I or L terminal on the alternator (whichever one is used). Notice in the schematic below how the "ignition switched circuit" works. Read the notes several times describing the use of the P-L-I-S terminals. You may use only one, two, or three of these, so be sure to identify what you have and what terminals are used. The wire from the ignition switch may have a relay before going to the I or L terminal. If so, and you get good voltage to the relay, suspect the relay terminals, or the wire from the relay to the I-L terminal as being the problem. All this is assuming that your 93 PA is using the "ignition switched circuit" and not the ECM or BCM. You need to do some in depth troubleshooting here.

[cityredneck1976]

thanks, yall did give me some other places to look at and troubleshoot from.

[Scrapper]

i'd try this then. the wires pliging into alt. tracy those down until you find the broken link and or wire...good luck again...

[cityredneck1976]

the ignition switch is the one in the column right? just double checking since i'v misplaced my haynes book.

thanks for all yalls help