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is it serpentine or vbelt setup?

 

Are you sure there's nothing wrong with your alternator and its pulley? Does it easily freespin when the belt is off with no grinding noises or difficulty or anything unusual? Also, is is definately tight and adjusted properly?

 

It is a V-belt setup, but the alternator belt to crank and water pump is a 5 groove serp. style belt. sorry forgot to mention that


The pulley freespins just fine. Im positive its not the alternator, I actually replaced the alt with a 140 amp thinking the old alt was just weak only to find out I have the same problem with the new alt....I had a whole thread about the issue and I tracked down all of the wiring on the alt and it is all good..I know its slipping, I tightened the belt tight, loose, looser and so on, The alt charges better with the belt tightest, but I know its not up to par and Im pretty sure its something with the crank pulley causing the belt to slip. I just didnt know if they could wear out and cause something like this or not.

 

If my pulley on the crank is bent or if my belt is slightly out of alignment could it cause this?

 

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if belt is riding in bottom of pulley its going to squeal

 

Sorry have to ask: Have you verified that the belt is the correct one for your application, that the pulleys are correct and that the belt is routed correctly?

JamesC

 

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If the pulleys look very highly polished, I'd suggest getting some red "Scotch Brite" pads (looks like red/purpleish steel wool sorta) or some finer sandpaper like 180 or 220 grit, and just use it to scuff up the belt surfaces of the pulleys. Just do it enough to take the gloss/shine out of it. That will help give the belt something to 'grip' and prevent it from slipping.

Any decent parts place should have those Scotch Brite pads, they would be in the bodywork section, with the sandpaper, masking tape, etc. I'd suggest those pads before sandpaper, as they are designed for scuffing smooth surfaces.

 

Ok I will try that as well, thanks for the advice!

 

If the pulley on the alternator (often moved from original alt to rebuilt) is worn out, it will slip. The groove where the belt runs will have a "U" shape instead of a "V".
A quick test to see if the pulley is slipping is it will get very hot.
Drop some water on the pulley after it has been run and if it boils, it's slipping (or if you're stupid, touch it with your finger). If so replace it.
Also, is there anything you're not teliing us, like a 2000 watt amplifier?

 

The pulley on the alt is new, but the crank pulley could be the culprit, I need to investigate it more.

I do have a system, but even when its disconnected and my alarm disconnected it still has he problem

 

I don't really know this type of setup, mixed serpentine and v-groove. Is it factory?

It almost sounds like underdrive pulleys are on the car as those tend to cause the alternator to fluctuate wildly and underperform badly, for me at least.

How is the belt tightened, with a belt tensioner or the old fashioned way, by prying up on the alternator and tightening a bolt down? If the belt were slipping, you'd hear an ungodly squeal coming from the belt.

Another thing, you haven't stated what problems this is causing other than the gauge is showing you in the red. How are the headlights, wipers, etc when you turn em all on? Normal/dim/slow/etc? You really want to put a tester on the alternator when the car is running to see what reading the tester gives you as your gauge could be giving you false readings.

 

i think we have the same setup. if the v-belt's in proper groves and it's slipping then the v-belt is probably too lose. be real careful about overtightening. general rule of thumb is 1/2 inch deflction per foot, but for accuracy IIRC it's 1/64th of an inch per in, so 10 inch distance between top of two pullys means 10/64th or just over a quarter inch. be careful if you overtighten is could ruin the alternator. when the car is idling if you see wobble then the belt is too lose. measure deflection with a straight edge over the two pullyes, pressing down on the belt and mesuring the distance. you hold a ruler in the center and measure. start with a 1/2 inch deflection per foot and gradually tighten more until slipping stops.

 

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Hmmm, is the adjuster hitting its limit when you tighten it? If you hear squealing sometimes, it may be because the adjuster is bottoming out before the belt is fully tightened... Also, are you chewing up belts? Are they frayed on the edges? That would mean alignment or damaged pulley issues.

Does the belt wobble or bounce while it's spinning or does it look fairly smooth. If you press down on the belt between 2 of the pulleys, it should only have so much "give". I don't know the exact numbers, but if you press it and it gives a lot, it's not tight enough.

Let's say that there is nothing wrong with your alternator or pulleys. Have you checked the wiring? Grounds, damaged wiring, etc. Also, you really should get a professional tester on there to determine the output when the car is running and report back here. If the output is below normal and you then do the same test with a another alternator, we can probably rule out the alternator as being the issue.

I know you said you don't have underdrive pulleys, but some of the symptoms you list really make me think that at the very least the alternator isn't being spun fast enough to generate normal voltage. I don't know if it's possible, but... You might look into a different pulley for your alternator, one that would cause is to spin faster, or more accurately, spin at or near what is supposed to be it's normal speed. Just a suggestion and I don't even know if it's a recommended one or even safe. I would suggest changing the crank pulley to accomplish this, but that would cause your other accessories to change as well. Unless your crank pulley is damaged. Probably couldn't hurt to yank that off and toss a new stock one on, and not a used one. Those can't cost much at all.

 

Just got done messing with it fot an hour or so, I just ruled out the pulley and the belt slipping/spinning issue and it is not slipping. Its starting to frustrate me badly, but I did figure out something very strange. I let it run until up to temps and once the fan kicked on my voltage went to nearly normal and out of the red, I though it was maybe a fluke so let it cool and did it again and it kicked on again after that, so im assuming its a wiring issue I just dont know what to check at this point.

 

we have ther same set up. i replaced my belts earlier this spring. one kept slipping and squealing. my brother-in-law (long time mechanic) showed me it was too lose. i cringed as he tightened but the squeal went away.