85 GLH volt meter bouncing

[QwikEVO]

Okay, I have been having this problem the past week or so. While driving, the volt meter will bounce and the lights will dim with the fluxing. I'm hearing a sort of grumbling noise coming from the passenger front along with the fluxing. I'm wondering if that's the alternator making the noise. Also, when I come to a slow roll (at a stop sign), the idle jumps high and stays there until I get moving again. It happens most often when I have the heater on. Without heat, it rarely does it...but it does occasionally. Also when I have the turn signals on with the lights on, the gauge bounces with the light flashing.


Here's a couple vids:

Volt bounce while driving:
http://www.youtube.com/watch?v=01Mu3lzl9Z0

Volt bounce with the turn signal:
http://www.youtube.com/watch?v=gxXobtIjesM

Now, is this an alternator gone bad, or a voltage regulator?

[black86glhs]

It could be the alternator. I have also seen corroded connections at the alternator, battery and grounds cause similar things.

[RoadWarrior222]

Though also check out your belt, tensioners and even the PS pump. The tensioner spring could be weak, or a bearing in a tensioner, idler, or any accessory on there could be dragging and making the belt slip. Could also be alt bearing rather than electrics.

[black86glhs]

Also, forgot about the pins at the rear of the instrument cluster. Most solder the pins at the base so they make a better connection with the printed circuits.

[QwikEVO]

Also, forgot about the pins at the rear of the instrument cluster. Most solder the pins at the base so they make a better connection with the printed circuits.

This would cause lights to dim, RPM's to rise, and driveability issues like hesistation with the bouncing?

[black86glhs]

No it shouldn't. It would be a possibility for the tach bouncing and the volt meter to act funny. The other gushes can act weird too.

[QwikEVO]

Well, I've narrowed it down.

It only bounces like that when A/C is on, or the defrost is on. Pretty much when the A/C compressor is used. Wonder if the compressor is dragging too much amperage, or I have a relay going bad...?

[85boostbox]

What kind of alternator is on this car?

[RoadWarrior222]

Could be marginal grounds or battery terminals, or other connections showing up under high load. Could also be that your high idle isn't right.

[85boostbox]

If he has the factory alternator then that is the reason. The L body factory alternator only puts out 65 amps which is not enough to run the efi. That is why in 88 they went over to the nippo alternator. If this still has the stock alternator convert it over tone nippo and you will no longer have voltage drops.

[QwikEVO]

As far as I know it's the stock alternator.

Battery terminals were replaced.

[RoadWarrior222]

Yah 65 is kinda weak sauce on anything other than a stripper carb car.

[85boostbox]

Exactly. I would change over to a nippo alternator and work from there if is stock.

[QwikEVO]

Ok, it was my experience in the past with a couple of my other Omnis that I went to the local parts store, got a higher amp alternator, and it was totally different than what needed mounted in my car.

Basically I have a stock 1985 GLH-T. What Nippo part # would I need to order to ensure it'd be a straight swap?

[Tbird232ci]

Have you checked all of the grounds? I have similar issues when I had the original grounds. I replaced all of the ground straps and added one or two with 8g and it smoothed out nicely. My cars don't have A/C so I can't comment on that.

[QwikEVO]

If I comes down to replacing all my grounds, I may go that route. I inspected most of the ones I was suggested to look at.

[85boostbox]

Got to look it up for a 88-90 omni/horizon for the alternator

[QwikEVO]

Got to look it up for a 88-90 omni/horizon for the alternator

And this will be a direct bolt-in? No modification?

[85boostbox]

Yep sure is.

[wallace]

Hey if the 88-90 alternator is a nipondenso you will need the mounting bracket for that alternator it is different from the one you have on the car now. The bottom bracket with the hockey puck rubber gizmo in it is the one I'm talking about.