OK, this is kind of a long story, so I'll start at the beginning.

I was driving from Virginia to Texas to visit some friends and when I was in Alabama I noticed my headlights dimming every once in a while. So I started watching the gauge and the voltage was dropping, so I figured the alternator went out. I wasn't near a big city so I kept driving, and noticed that the voltage not only dropped, but went up as well. (I'm talking +/- 3 volts) I made it to Meridian, Miss and stopped for the night. In the morning the only alternator I could find was a reman'd Arrowhead. So I took it and went on my way. I made it to TX fine.

However, a day after I get there that alternator dies too, but it wasn't jumpy, it just wasn't putting out enough voltage. So I bought an Ultima reman'd Delco alternator (the best I could find) and put it on. This was fine for a couple of days, and then it starts jumping high (only, not low) like I described before. So I swapped it out for another before I tried to head home. I got about an hour into my trip and it started jumping high too so I turned around.

So I decided to check all of the wires in the charging system and the only one that came up bad was the battery-to-block ground cable, it measured at 1.0 ohm. After replacing that it was better. I made it back to Alabama before it started jumping high again. And since it was only going high I just said "screw it" and kept going and made it back to VA.

But, since I've been back the problem has gotten a little worse. Now anytime that I drive for more than an hour the voltage likes to jump high, only it's even higher now. In the past few days it's pegged my dash gauge out a few times and set a code (53 - if that helps anyone). I tried replacing the ignition coil too since that was the only thing I could think of that generates a higher voltage, but it didn't help.

Just to clarify, when it jumps, I mean that it'll go that high and stay there for 30 sec - 1 min and then drop back to normal for a min or two and then repeat.

Does anyone have any ideas? I'm fresh out. It seems to me that it's the voltage regulator, but since it's in the alternator I don't know how to test it. And since it doesn't happen on short drives I'm guessing it's also heat related too.

Thanks for any input guys.

 

Doubt this will help any but, make sure there's a good chassis ground as well ( - battery to chassis or the original ground strap from the block to the firewall)

 

Wow that one sounds interesting. I'd agree with you that the culprit may be the voltage regulator if it spikes high. The problem I'm having with that theory though is the fact that its happened to 2 other alternators with internal regulators. I'd find it hard to believe that 2 different manufactures have problems with voltage regulators. My thoughts are to continue checking grounds. Maybe, make sure the alternator case is grounded well to the engine by the mounting points. Battery cables clean and tight?. ground cable to battery is clean and tight at the engine block and to the body {other that the one you fixed}. Maybe have the battery tested. I have seen one battery at work that had a cracked plate inside of it that created an internal short. That could make voltage fluctuations. Anyway, just some ideas to throw at you. Let us know how it turns out.

 

I would say check the connections on the starter solinoid, a bolt could be loose. Also check the fuse links while you are at it. Before you start taking things apart, put a meter on the alternator and see what it is putting out (while the car is running of course), then try to shake, twist, jiggle wires around to see if it jumps around a little bit. That might help to generalize the problem some.

And you never said anything about the battery, I assume you checked that.

I had this problem before also, but mine turned out to be the voltage regulator, replaced the alternator and it has been fine since.

Just some thoughts, hope this helps.

 

In my '92 f body GM service manual I have here at home, a code 53 is a Pass-Key code for a TBI vin E engine. Either this manual is not compatable with your car or something maybe went screwy when you burned your chip? I don't think a Pass-Key {vats module} circuit fault would have anything to do with voltage fluctuations. Or like I said maybe a code 53 was something different in '88.

 

Don't overlook heat. Something may be drawing too much current and/or placing too much heat around the alternator. If the voltage regulator overheats it could spike high. In that case it wouldn't matter if the regulator was a day old or a decade old.

 

The battery to chassis ground is fine, I checked that when I replaced the one to the block. Haven't checked the block to chassis strap on the back of the engine though, I'll look into that.

Both battery cables are perfectly clean and tight too, no corrosion at all. I also had the battery tested while I was in TX, forgot to mention that though. I had it tested at an Advance Auto with a machine that actually put a load on it, but it came back fine.

I'll check the starter solenoid connections and alternator output voltage as well.

I don't know what the code 53 is either, my Chiltons manual doesn't go that high. I know it's no from burning the chip though. Cause I've been doing that for over a year and it's never tripped a code. Also the SES light comes on when the gauge pegs out, and goes off when the voltage drops back down, so it's related to the voltage somehow.

Thanks for the ideas guys, I'll post back with some more info tomorrow probably.

 

Code 53=overvoltage

~M~

 

OK, small update:

On my drive home tonight the voltage was spiking up to 18 almost constantly, so when I got in the driveway I whipped my multimeter out. At idle the gauge inside never got above 14, but when I tested the output voltage of the alternator it was 22.5V! (I measured from the terminal on the alternator to the bolt where the battery chassis ground is tied to if that matters). My question now is, when the gauge inside is actually up near 18, what voltage is actually being put out? I'm kind of surprised that something hasn't fried yet.

 

Its sounding more and more like a voltage regulator problem.... sorry didn't mean to mislead you about the code 53, I only have one gm service manual here and its for a '92

 

Another update:

I checked the block to chassis ground strap today, and it has a resistance of 4.5 ohms. So I'll replace it tomorrow.

Do you think that the combination of both of the ground straps being bad could've kept knocking the voltage regulators out? Because I'm thinking about trying another one after I replace this ground strap and see what happens.

 

Have you measured the resistance of the charging wire yet? Also, try measuring the voltage drop across the charging wire with the car running.

 

Yes, the charging wire has no resistance, it reads as a dead short.

I also checked the starter wires today, and they were snug but not tight, so I tightened them.

I think it was the block to chassis ground strap though. I replaced that today and just got back from about an hour drive and it ran absolutely perfect. I guess I'll just watch it for the next couple of days and see if it acts up again.

Thanks everyone for all of your suggestions.

 

where is the block to chassis ground located

thank you

 

Mine is off the back of the passenger's side head.