Charging Issue..

[n1265]

Hi guys,

I am having a charging issue that I have never had before and would like to know your thoughts on the problem, The truck is a 1977 M880 :

A couple of months ago the truck was over charging ( steadly ), I took it to advanced to have it tested and they said the regulator was bad, Put a new one on it and all was well for a while. But now while driving the headlights will all of a sudden get super bright ( brighter than the high beams ) the amp gage will peg all the way to the charge side, and some times the alternator mill make a squeeling noise ( almost like a belt slipping ) This condition will happen at random at highway speeds and last up to 5 seconds before kicking down to a normal chargeing level (sometimes it only lasts for a brief second). It will happen with the lights on or off, but I can not get it to happen at an idle. when it happens at highway speed, immediatly taking my foot off the gas does not force it to kick down from the high charge. It seems to come and go at random, It happens about once every 1-2 miles.

The alternator is a 3 year old re-man with less than 5 K miles on it.
The voltage regulator is 2 months old with less than, 1K miles on it.
The battery is dated 3-04 with less than 10k miles on it.

Any Ideas on what the problem is ?

[DODGEBOYS]

either the new REG is go,in bad or its not grounded right

[n1265]

I have a ground wire ran to the VR to the small lead that grounds the driverside fender to the battery, I suppose it could be bad.


Let me ask you guys this :

It is a huge PITA for me to crawl into the engine compartment to deal with anything on the back side on the motor / firewall. Would it hurt anything if I spliced in a lenght of wire and re-mounted the VR on the drivers side fender ?

[ram fan]

My '77 883 does THE VERY SAME THING. It hasn't done it for a few months, but as you say, it will come and go at random. My ammmeter was dead when I bought the truck, so I had no reading to go by, but it had to have some serious overcharge to make the lights THAT bright. I did change the VR about a month ago and have done a fair amount of driving since then and no problem. I too am thinking that's the problem, but not sure. I will say this, the last VR I bought over the counter lasted maybe a year before it was shot, so I'd buy another and keep it with you in the truck. I had one go bad on me about 20 miles from home during a fall evening. Thankfully my bro in law lived very close to the area, brought me a hot battery and I made it home. I've got enough parts short of doing an engine overhaul kept in my toolbox, you never know what can go wrong at any given time with these beasts. Another thing too, the wiring in these trucks are most always hacked and spliced. It never hurts to go through all the grounds and make sure they're good. It took me a couple of weeks (off and on) to get the wiring up to snuff. If you find out the problem for sure, let us know!
Craig

[pwdave]

Bad diode in the alternator. been there, done that, thirty years ago. when you change the alt. change the reg. also. Dave.

[Deathdeelr]

I agree with Dave. To answer your other question, yes you can change the location of the voltage regulator. Modifications to my system to prevent this issue are:

- I ran a ground wire from one of the mounting bolts for the regulator to the intake manifold. I found an old rotten section of a braided ground wire when I rebuilt the motor that I believe was originally for this purpose.

- I was able to use a thicker belt for the alternator that fit the pulleys. My original setup on the 880 was using a 1/2" pitch (top width) belt to drive the DC generators for the radio set (actually an M882). The narrower alternator belt used in civilian applications tended to squeal incessantly at speed. I actually believe I burned out one alternator and a water pump because I had to tighten the belt to the point of bearing failure. There's a thread somewhere here about this particular point. Switching to the wider belt eliminated my squealing.

- I did the ammeter bypass we discuss on this forum and repaired the voltmeter the military installed in my dash. My voltmeter shows a system voltage of 14 volts whenever the engine is running. Usually that calms down a bit on long runs to 12-13 volts but I believe that's due to the regulator doing it's job on a healthy battery.

[n1265]

Well, the new Alt. fell off the bench and I am wondering if they are usually still good after a fall like that ?

[pwdave]

Luck, or lack there-of

sounds like the crap that happens to me, take it to a different parts store and have it tested before you put it on. was removing a tachometer from the box once and it slipped, fell, and hit the floor, tachs are VERY delicate, o well 75.00 down the tube. Dave.

[n1265]

I did exactly that and it tested ok, Put it on the truck and the gage in the truck reads to the neg side (slightly more than before ) So I took the truck
( with new alt mounted ) back to Autozone and they hooked it up to a Machine and told me everything was ok,

However the printout from the machine says :

Battery test: Good Battery
Starter test : Cranking Normal
Charging system test : High voltage
No load = 15.49v 5.0 A
Loaded = 15.52v 21.8A
Ripple = 32mV

*** ?

Anybody know if the above readings are anything to worry about ?
What is " Ripple " ?

[KRB64]

Where you get your regulator makes a difference. You take your chances at parts stores. Go spend the $45 for a Mopar and forget about it.

[OLD DODGE]

What is " Ripple " ?

Ripple is the amount of AC voltage in your DC circuit. That reading is very low and nothing to worry about. The charging voltage might be a bit high, they are normally around 14 volts on the 12 volt vehicles I have worked on.

[Deathdeelr]

I'd bet with those numbers you're grasping at straws. I think your ammeter is reading incorrectly.

[n1265]

Well here we go again, took the truck out for a cruise and the amp gage swings over to the far right when giving it some gas, then comes back down to normal at idle. I took it to the parts store and had them hook the machine up to the truck and the results are :

16.73v unloaded
14.88v loaded

I am guessing its the VR even though it is only 6 months old and has less that 1k miles on it. (The New ALT is 4 months old and only has 625 miles on it.)

I re wired the ALT and re located the VR to the fender when I replaced the ALT. All wiring and connections to the ALT and VR are new with new soldered connections, the grounds have been checked and are good.

Am I missing something here , or is it hard on these trucks to sit in the yard for two weeks at a time ?


For those of you who have been following the thread about the small crankshaft pulley on the M880's, I am wondering if this could be causing the VR ( or the ALT ) to go bad premature ?

[KRB64]

Where you get your regulator makes a difference. You take your chances at parts stores. Go spend the $45 for a Mopar and forget about it.

And I just had to eat my words... my Mopar VR just crapped out at less than a year old. Oh well, guess they all suck now.

[n1265]

Thanks for posting about the Mopar VR, I was currently waiting till Monday to get one at the dealership.

Did the Mopar VR come with a warranty ?

The Alt. and VR I have had on the truck came from Advance Auto The VR has a 1 year replacement warranty. I was not even going to get it replaced threw them because I am tired of replacing them. Is there a better source for these things ? Is there another known problem that makes the VR go bad
( except for the dioads in the ALT ) ?

where is the best source for new parts to rebuild the ALT with Quality parts ?