supes6

For some reason my gauges have started to bounce about 1/8" up and down after the car is warmed up. It's only an issue with the temp gauge and voltage guage, everything else is fairly steady. Volt gauge is bouncing between 14-15 volts... and I just had the voltage regulator replaced maybe a month ago. Is this an issue with the alternator?

River

Nope.

Grounds, grounds, and...wait for it...more grounds.

Clean with coke mixed with baking soda. Clean every ground from bumper to bumper. Use light, theeeee lightest coat of dilectric grease.

Also, pull your cluster out and clean all the contacts (ribbons and metal ones) with rubbing alcohol. Make sure you pull the football looking contacts apart behind the cluster housings and shine those guys up too.

supes6

I don't know River... I cleaned all the grounds within the past year, along with new battery/alt cables and a mostly new engine harness. Never had the bouncing needles until just recently, after I had my quest alternator fixed. How does a bad ground cause the voltage to fluctuate?

River

Power flow my friend. Things need to be just so on our cars.

When I did the ones behind the cluster, It stopped the voltage one from bouncing around a bit. I just did the ones under the dash, so I'm excited to see the difference. It used to move/bounce a lot, and now it's like a tiny bit if I turn on fog lights/heater element. Make sure your relays contacts are all clean too. And, battery cables...check those out. Contacts need to be nice and clean on both points.

Grounds should be done once a year, prolly more when it's cold. I just noticed yesterday a couple that aren't shiny anymore. And I did my grounds last March. Go figure?!

Fun stuff, electrical with our cars...lol!

kingston944

Well want electrical issues get lucas like on my old MGB.

ernie9468

I'm old enougth to have owne an MGTD /MGA/TR3 & a XKE, lol agree with you can't beat Lucas the prince of darkness.

Yarf

Supes6
Connect a meter across the battery terminals with the engine at idle, does the voltage reading bounce like the voltage gage in the instrument cluster?

supes6

Just tested it, the voltage at the battery looks pretty steady - but it is reading 15.3-15.4 volts.

Yarf

The voltage is too high should be approximately 13.5 volts. The voltage regulator does not appear to be working.

supes6

Yep.. I'll have to pull the alternator again and take it back to the repair shop.

River

Wait, BACK to the repair shop?! As in, it's been there already?

Brutal.

JohnKoaWood

Karl,

I would consider taking the alternator back to where you got it, and getting a different one, there has to be something in your fiedl coil causing it to eat regulators...

I have done the Quest swap on a few cars, and have yet to see a single one acting like yours... unless there is some other wiring fault in your car causing it, it has got to be a fault with your alternator..

When you swapped your battery cables, did you install a new alternator to starter harness, or just the cable between them keeping the other two wires from the firewall to the alternator and starter? (This is a difference between a couple different cable options... some replace those two wires, some dont!)

supes6

I ran new wire pretty much everywhere. Everything connected between the battery, alternator, and starter is new. Only ones I didn't replace were the leads from the battery to fuse box. The weird thing is that both of the regulators failed in different ways.. the original one that came with the rebuilt alt. just stopped charging, now this one is charging too high. I think I need to check with the shop that repaired it and see what exactly they did.

Mrmerlin

I would suggest that you install a new Bosch regulator not the cheap units