Another Alternator Question

[surfdog4]

The voltage gauge in the dashboard jumps up and down at a rapid rate..between maybe 10 and 16V..doesn't seem to be linked to any particular loading..i checked the voltage at the battery with my Multimeter and it is rock steady at 14.xxV.

With all the other electrical contact issues i've found on this car, i wouldn't be a bit surprised if the dash gauge has a problem, but i would think if the voltage coming out of the regulator was indeed changing that much I would see something at the battery terminal?

I haven't pulled the alternator yet to see exactly what i have (i know i have a stripped bolt on the upper hole) but i was hoping there might be a "quick and dirty" check on the alternator so i could order one if necessary and do a swap if need be. (I've seen some Bosch units with internal regulators listed)

Thanks

EDIT: I have an interesting glitch..everytime I click "Post New Topic" it automatically puts me in the 911 forum..guess this is a sign

[jabb]

A good way to see voltage regulation is a night with the headlights turned on.
Sit there at idle and see if they fluctuate. They should not....

[84porsche9113.2]

although you don't have a 911, it seems to me that if your gauge is jumping it may be a bad connection. as long as you have 14.xx at the battery, it would seem that your alternator is working properly and the gauge would be suspect. i would say either the the connections at the gauge, or read the voltage at the gague and trace the wiring back from that point to figure out where your bad connection is. it may be simply a bad ground too, you could use a good grounding source and connect it to the gague ground point and see if that fixes it (though I was told the ground should be connected as close to the battery ground as possible for accuracy). the above would be my shot at it...

[surfdog4]

Thanks...i think the consensus is that the gauge connections are bad..i did get one suggestion to look at the voltage at a point under the hood..away from the battery (928)..so I'll give that a try before i start disconnecting things!

[scarceller]

I would test the voltage right at the gauge with a DigitalVoltMeter (DVM). I would connect the DVM ground lead to the same ground point the Gauge uses (maybe even the gauges metal body) then the DVM '+' lead to the wire feeding the 12v to the gauge. Leave the gauge connected while you do this. If the gauge is jumping around and the DVM is steady you have a bad gauge. If they both jump around the wiring is bad. If the later occurs try just moving the DVM ground from the gauges ground to a better ground point and see what happens.

Hope this helps.

[surfdog4]

I figured I would eventually have to pull the instrument pod anyway so I'll check it there as well...one thing i plan to do is pull out my old analog multimeter, since i've never developed a trust of these 'fancy smanchie" DMMs!