Well, I figure that I should speak unadulterated English this time and leave out the thoughts of adultery...


My voltage in the truck continues to act up once every hour or so. I poked around, nothing loose.

Usually I start the truck and it works fine. The voltmeter sticks to middle range, then fluctuates a little bit back and forth until it warms up. (I hear that this is normal grid heater fluctuation, correct?)

Once I get on the road though, the volt meter tends to shoot to full swoop and stick there. This morning I was driving about 35 and the radio cackles and dies. Glance at the voltmeter real fast, it's over the "18" all the way on the right of the gauge. Turn off the radio so it doesn't melt, the volt meter still stays there. Turn off the truck and restart it, and the voltmeter still is stuck at 18.

Now here's what's probably the important part. When the voltmeter read "18" I was at idle. As I accelerated the voltmeter kept going up with the engine RPM's. I accelerate a little bit and the voltage goes up a accordingly until it maxes out. I slow down a little bit and the voltage goes down again, but not below the 18.

I tried turning the engine on and off about three times and each time the voltage stayed at 18 or higher. (I was sitting in traffic at the time). All of my gauges worked, but my radio died as soon as the voltage spiked the first time.

The high voltage lasted about three minutes until I got out of traffic, and then it went back down to regular levels. I was afraid of going onto the freeway and running at a high RPM, but the gauge was fine now so I did it anyways and it didn't act up again.


Anybody have any new ideas? I figure it's the alternator, but don't know if it means that I need a new one or just a new voltage regulator or something.

Thanks for any help.

 

Do you actually have a voltmeter or an ampmeter? Mine is an ampmeter in the dash.

Either way, it's probably a bad ground on the voltage regulator or it's bad. It's on the upper firewall about in the middle with a 2 wire plug in it. Unplug it and unbolt it from the firewall and then clean orr the dirt' paint etc... and bolt it back. If you have some external star washers they will help in grounding also. Put a couple between the regulator and the firewall so the sharp points will bite into the metal.

If that doesn't fix the problem then get a new regulator. They're about $12.

Edwin

 

I don't know what the gauge is. The gauge with the little battery on it that goes from "8" to "18" and always sticks in the middle.

Is it a voltmeter or ampmeter? Ammeter? Retard Electrometer? I know it's not an ohmeter, at any rate.



Okay, that's good about the "12 dollars". I'll go out and check that as soon as it stops raining and see if it happens again.

Thank you, resident electrical engineer.

 

You have a voltmeter. An ammeter would say "60" on each end.

 

Sounds like you got a voltmeter alright. The jury is still out on which is more useful. I would prefer to have a voltmeter sense the voltage at the battery terminals but it's doubtful anything factory would be connected this way.

My ampmeter is a shunt type (factory) which measures the voltage drop across a calibrated section of the wiring under the hood. More current = more voltage and the polarity of the voltage shows the direction of the current into or out of the battery. It's a D-0-C type with zero in the middle. Of course it isn't calibrated and only shows relative current.

Aparently somebody re-routed the grid heaters directly to the battery on the wrong side of the shunt so when my grid heaters are on the ampmeter shows full charge which is just plain wrong.

Sorry to be so technical. Us engineering type are like that. Ask us about hanging a picture and we'll tell you how to build a house.

Edwin

 

If your volt meter is reading correctly, you may have a bad voltage regulator. It sounds like it is calling for more voltage when it isn't needed. If it continues it will most likely fry your battery and/or altenator. I don't know about the older trucks but the '92 regulates voltage with the PCM.