Electrical: amp gauge bouncing on M16

[kfnut]

Hi
My amp gauge bounces around rapidly while driving . Can't find any reference to this problem in any service manuals or Motor's books . Any ideas to solve this problem would be appreciated .

[Chucks Stude]

You might try cleaning the contacts on the voltage regulator Fine emery cloth, or very fine sandpaper will work. If not, that, than look at the condition of the brushes on the back of the generator, they may need replacement, or cleaning.

[jd-stude]

I had a similar problem of the needle bouncing from one extreme on the gage to the other. I initially blamed it on the cycling of the electric fuel pump the car came with. The car had been sitting for and not started for 10 years before I got it. I tired to clean the regulator contacts but it didn't help. It behaves normally now after I replaced the regulator.

Ken

[Bud]

Replace the regulator as trying to clean the contacts usually causes problems with the adjustment. Also check the condition of the generator brushes and be sure that all of the connections between the generator and regulator and also the ammeter are clean and tight. Bud

[nvonada]

How much does it bounce? 10%? 50%? 100%? Does it vary by RPM?

What is supposed to happen:
Battery low and the RPM above idle -- For example right after you start. Steady charge on the meter.
Battery fully charged and RPM above idle -- Regulator will cut in and out to keep the battery charged. You might see some "bouncing" of the needle here but it should be more of a 5-10% of the range thing.
Idle -- At idle the generator is not putting out much at all. You should see close to 0 or a discharge depending on the electrical load.

[jclary]

Gee folks...what happened to the "cheap" fixes (checks) first? Like making sure that all wires are tight on terminals. Remove battery connections and give them a good cleaning. Check for loose connections at the amp gauge. Spray a little contact cleaner into the ignition switch and operate it several times to clean off any tiny corrosion that could be interfering with good current conduction. Check for cracked, frayed, or missing insulation.

Before ripping off your regulator cover, how 'bout taking the dust cover off the generator and give each brush a gentle nudge toward the armature. Although the brushes are spring loaded to make contact, I've had them to hang up. If they are about worn out, a good inspection is due anyway to see if replacement is needed.

My last resort would be to open the regulator. Then... a jeweler's touch is required to delicately clean those contacts without changing the operational values that control the balance of how they interact to draw and charge current between the generator and battery. Unlike solid state electronics, these old "electro-mechanical" systems operate under a broader spectrum of values than modern systems. None of my vintage vehicles have amp gauges that operate exactly the same. Some, nearly show neutral charge under normal operation, others, show a constant charge higher except when idling. All somewhat "flutter," but I wouldn't call it a bounce.

[kfnut]

Thanks for the input . I will give each suggestion a try as soon as possible . To answer a question . When I first crank the engine I get no response on the amp gauge . After a bit it starts to register but bouncing around . It does this all the time and I am worried it will ruin the gauge . Due to the upcoming holidays and a trip to Moultrie Ga. swap meet , it might be awhile before I can check everything . I will post back what I find .
Thank you

[Mrs K Corbin]

I'd take care of that soon, I nearly lost my 2R5 in '90 when the guage pegged and caught fire under the hood......
had to disconnect the battery and quick fire-fight..... lucky the terminals are kept loose and the fire hadn't spread.

[Xcalibur]

Another possibility and one I ran across some time ago is that the thing has just been wired wrong by some well-intentioned... twit. I encountered this a while back on a vehicle that had been to Europe its entire life. It was repatriated with a "bouncing" gauge AND was slow to start charging after each start-up. Looking at the wiring diagram and tracing how the car was wired I found several changes from the Book. Putting it back correctly AND a new regulator. and all was well. SO many things can be wrong!!! Best of luck.

[kfnut]

Thanks again for the info . Xcalibur's post sounds just like my situation . I will be going thru everything in the next couple of weeks as time permits . The wife has a priority "Bedroom job " first . I will remove the generator , disassemble and dress the armature in the lathe , clean everything , dress or replace the brushes , paint and detail it while it is out . The same for the regulator and check all wiring for clean connections , tightness and proper location . I will report what happens . I might need more help with it .
Thanks