florida2002m3

Noise When Turning On Headlights

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74 carb'd.

 

Car sat for a few months, no battery tender :(

Charged it once, drove it for a few weeks without any issues

 

Other morning, about 50 F, she turned over very very slowly, then sped up... Vroooooom.

I noticed a high pitch, faint, jingle/whining noise from front of engine.  Only at Idle, goes away at 1200 ish.

It was 6am, so I shut her down and took another car.  Put the charger on for the 8 hours at work.

 

Came home, she started right up, no noise :)

 

Next morning, same thing, same noise at idle.  So I revved her (2K) for a few minutes, back to idle, no noise :)

Drove to work (15 minutes), turned off, started again.... vroom right away :)

Get in her after work..... slow turn overs, faster, faster (30ish seconds).... vroom, sound. then goes away.

Get home and Finally have time to actually experiment

 

With a new charge on the battery (which may be on its way out, 5 years old and neglected??)

Starts right up, no noise, UNTIL I turn on the headlights, then the noise is there at idle.

 

Charged overnight, started right up, headlights make noise, drove to work.

I expected it to not cooperate when leaving work 8 hours later......... but oh no, starts right up, but noise with headlights.

 

Wohoo, narrowed it down to electrical, I think :)

 

Atl is a rebuilt 85amp with new poly bushings, about 4 years old

It has always done something a little weird, when the car is started the alt has no output, until the rpm's pass 3K.  At that point it jumps to 13.7ish volts and starts charging all the way down to idle level rpm's

I know the alt is putting out, I can disconnect the battery and run her just fine.

 

 

Will the Alt make a little noise if it is really stressed? As in, my battery is on the fritz.... stressing the Alt?

Im hoping someone else has had this symptom in the past.  I plan to jump into it this weekend, but figured I would first consult the wise council of FAQ!!

 

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How is the tension on the alternator belt? Have you tried cleaning the grounds in the engine bay yet?

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The belt deflection between pump and alt is about 1/2 inch.... but I can turn fan and/or alt by hand and the belt slips.

 

I have yet to check the connections, but all of that had been robustly done a year or so ago.  

 

Im putting my $ on the belt.  But the weekend will tell.

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Check that the alternator mounting points are all tight - including the arm that runs to the front of the block.  If loose, won't maintain tension on the belt.

 

John

04 Polaris 2002

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I think it's the alternator itself--I've noticed that they will sometimes whine when a heavy electrical load is placed on 'em (such as turning on the headlghts--esp when it's trying to also recharge a low battery.  The heavy load makes the fan belt work harder to turn the alternator.

 

Try this--instead of turning on the headlights, try turning on the heater blower (another heavy current draw) and see what happens.  Bet you'll hear the same whine!  It may well go away when you replace the battery (or fully charge the one you have, presuming it'll take a full charge).

 

mike

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Atl is a rebuilt 85amp with new poly bushings, about 4 years old It has always done something a little weird, when the car is started the alt has no output, until the rpm's pass 3K.  At that point it jumps to 13.7ish volts and starts charging all the way down to idle level rpm's

 

This is normal and happens because the alternator has not yet spun fast enough to become self-actuating. 

Beaner7102

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Not normal for any alternator I've ever used... sometimes, if idle's low, voltage will sag- but the jumpy thing makes me think

something's not normal with the voltage regulator or its wiring.

 

But my vote's on either the belt

or the alternator itself.  As in, something

inside it's vibrating when it's loaded.

 

fwiw

 

t

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Quick note, the temps during the day are in the mid 80's.  Nightime is in the low 50's, very weird Florida spring?!??!

 

Started right up after work yesterday :)

Drove her home, did not hook up to charger, Cleaned and checked connections, all looked good

 

Started her about 2 hours later..... everything normal :)  ran her for 15 minutes

 

Started her up 3 hours later.... everything 100%, no noise :)

 

Parked her for the night without the charger, feeling overconfident...... never a good idea with this car

 

Got up this morning a little earlier, very slow turnover, got faster, then faster, then started right up

I did NOT engage the alt (3k+ rpm), no noise.  headlights on, no noise

I then engage the alt, headlights get brighter.  Rpms's go down to idle....... jingle jingle noise, softer if i turn off headlights.

 

This is where it gets good:

I grab a light and belt conditioner, open the hood

I spray a little onto the belt @ the alt pulley (I realize I shouldnt have sprayed it so close to the alt, but not important at the moment)

~~The noise goes away, I turn on and off the headlights, rev it a bit:  Noise is gone

 

Recap:

Belt is loose, I will check for glazing when I tighten it

It was tight enough to turn the alt with minimal load, but heavy load it was slipping a bit (not a normal slipping noise at all)

 

Next Consideration:

Battery CCA is low at the moment. A 5 year old, neglected, Duralast 65 DL with 750 CCA

The drive to and from work is only 15 minutes.  A freshly charged battery should be able to start, run the car with a little charging, sit for 8 hours, start, run again for 15 minutes, sit for 15 hours, and start again, correct?

As stated earlier, the alt puts out enough to run the engine without the battery, so load on battery should be minimal during driving

 

Current Chronological Hypothesis:

Battery/car (belt) sat for 6 months, battery got too low for its own good, charged on charger

Belt was tight enough to keep the battery limping for a few weeks

Florida spring weather swings catalyzed the failures

Belt started to stretch a bit, less charge to keep it limping

Battery started to show signs of neglect

Battery is now beyond nightly charge and full alternator charge "recovery"

 

Conclusion:

Tighten/replace belt

Replace battery

 

 

I appreciate the knowledge of the group so please read through my ramblings......... and let me know if you would draw a different solution from all of the symptoms/findings I presented.  I would be much more than happy to not pay $150 on a new battery :)

 

THANKS!!!!!

 

 

 

 

 

 

Slightly off topic

I sprayed the belt conditioner right in front of the alt, and now the alt appears to be making a new sound..... could be a "conditioned" belt slipping or could be a dislike of the conditioner in the alt???  Any experience on this?

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Check the three prong connector on the back of the alternator.  Make sure all three alternator prongs go into the connector contacts.

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Update:

 

Put in new battery

Tightened belt

 

Everything is fine now, but I fear I tightened the alt belt too tight.  I get a whining noise from the alt that increases with rpm.  Sounds like a SC :)

 

When I press on the belt between water pump and alt pulley I get about .375 inches of deflection.  I am going to loosen it a bit and see what I get.

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I loosened the belt, so I am now a bit looser then the .5 inch.

 

Still getting the whining.  So I sprayed the belt again.  Below the ALT by the crank pulley.

 

Sound goes away for about 20 seconds, then comes back.  Any ideas besides a new belt?

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I loosened the belt, so I am now a bit looser then the .5 inch.

 

Still getting the whining.  So I sprayed the belt again.  Below the ALT by the crank pulley.

 

Sound goes away for about 20 seconds, then comes back.  Any ideas besides a new belt?

Was your problem solved?  If so, what was the solution?  

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Have you replaced all the bushings that connect the alternator to the car? If those are bad, you will never get it right.

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