Alternator problems

[dankwun]

Im having a problem with my alternator charging at idle. At idle the battery is only putting out 12.7 volts which is what it puts out with the engine off. When i rev the engine to 1100rpms the battery puts out 13.9 volts. What would cause this? What is the normal idle for marauders? is it possible that my car is idleing low? or maybe the belt is a lil loose?

[Blk Mamba]

I had Alt. problems for about three months, check my posts on it, it was a bad Alt., bad pulley, and a broken wire.

[Bobmiddle]

I think stock idle is like 650 rpm. If you have a xcal you can bump up the idle rpms but you wont want it to idle at 1100 rpms.

[Paul T. Casey]

Perhaps you have u/d pullies? Mine runs reall low voltage, maybe near 10 at night when lights, radio, a/c, and blinkers are on. Doesn't seem to hurt anything.

[dankwun]

how do i know if i have under drive pullies? i bought the car used...

[red]

how do i know if i have under drive pullies? i bought the car used...
Do you still have overdrive? :D Take a picture of the crank pulley (bottom center) and we can tell you.

[dankwun]

would a u/d pulley happen to make a whining noise...almost like a blower

[red]

would a u/d pulley happen to make a whining noise...almost like a blower
That could be a pending pump failure, bad pulley bearing, bad belt tensioner, etc. An underdrive pulley simply underdrives (runs slower) belt-driven accessories to reduce parasitic power loss. They're suggesting that causing the low voltage as your alternator is belt-driven. If this is the case, the correction is to bump up your idle RPM using a tuner.

[chader]

would a u/d pulley happen to make a whining noise...almost like a blower


I think he maybe refering to the clutch noise on the alt.?????

[dankwun]

yeah i changed the pump and the belt tensioner..the pulley bearing is something i was thinking of looking into..it just seemed weird because it makes that noise like a blower...(like and extremely loud blower) a real loud whining noise...and it also is at low voltage at idle..i guess im going to see if the bearing the pulley or maybe changing the pulley helps..and post a picture to see if you can tell if i have a u/d pulley...thanks guys

[red]

the pulley bearing is something i was thinking of looking into..
Just for clarification, I was referring to the idler pulleys (there's a ribbed and a smooth one). The bearings in my smooth pulley went South a little while back. Also, your other post says you replaced the power steering pump. Have you looked into the water pump? Are you able to tell generally where the sound is coming from? One other thought, you can get a nice squealing if your belt's glazed over.

[Aren Jay]

Stock idle in gear is around 525-540 range. Bit higher out of gear.

[dankwun]

yea.. i also changed the belt and water pump. my next step is to check the pullys.. but would a bad pully cause low voltage at idle?

[dankwun]

when i took the picture i now see what the problem is.. That pully definitely doesnt look too healthy. but do i have underdrive pullys?

http://i73.photobucket.com/albums/i229/dankwun/IMG_1817.jpghttp://i73.photobucket.com/albums/i229/dankwun/IMG_1818.jpg

[red]

when i took the picture i now see what the problem is.. That pully definitely doesnt look too healthy. but do i have underdrive pullys?
Looks like a stock crank pulley/damper to me.

Again, the idler pulleys are what I'm referring to as possible sources of noise. They're the small smooth and ribbed pulleys on the upper left. The parts I used were Dayco 89007 (smooth) and FoMoCo YW7Z-8678-AA (ribbed). I believe I got the Dayco at AutoZone or Advance Auto. The Goodyear and other pulleys I found were different sizes than stock.

As chader suggested, the clutch on the alternator could be going, which could be another explanation to the noise and low idle voltage. What RPM is your car idling at? As reference, mine idles at ~800 RPM per my tune and idle voltage in drive with foot on the brake is in the mid 13V's.

[red]

when i took the picture i now see what the problem is.. That pully definitely doesnt look too healthy.
BTW, I wouldn't worry about the rust on the crank pulley if that's what you're referring to. It's completely normal. The only ways the pulley itself causes problems are if there are issues with the belt mating surface (imperfections, etc.) or if the pulley is out of round. The bearings (for example, in the idler pulleys) can go bad and is detectable by visually inspecting while the car is running and looking for vibrations, by feeling for play or grinding while the car is NOT running, or by listening for noises coming from the pulley. Obviously, keep a safe distance from the belts and pulleys while the car is running.

[red]

Stock idle in gear is around 525-540 range. Bit higher out of gear.
Mine never idled that low stock and maybe this is part of the cause of your stalling (http://www.mercurymarauder.net/forums/showthread.php?t=39629). I know others have said their idle is this low, but I seem to recall mine being just above 600 RPM when stock.

[dankwun]

I changed the alternator already and it still does the same thing, which means the clutch wouldnt be the problem. and its idling around 700 rpms.

[dankwun]

also do u thinks its possible that if i put a ribbed idler pully on that a little bit bigger that the alternator would spin faster at the same idle or would this mess with my idle?

[justbob]

This sounds exactly like what mine was doing. Idling at night with lights on and music playing the guage would drop fast and lights would dim. This only happened a couple times a month.
Then when i did my trilogy which requires removing the clutch and flipping the alternator backwords and extending the harness nothing has ever happened again. So something i did seemed to have fixed the problem. But when it used to happen i would have to hurry up and put her in neutral and everything would be fine.

[dankwun]

im wondering if maybe the harness has somethin to do with it.. the clip seems a little loose.

[red]

also do u thinks its possible that if i put a ribbed idler pully on that a little bit bigger that the alternator would spin faster at the same idle or would this mess with my idle?
A different sized idler pulley will not effect the drive speed of the alternator. Reducing crank pulley size or increasing accessory pulley sizes will underdrive. Accordingly, doing the opposite has the opposite effect: increasing crank pulley size or decreasing accessory pulley sizes will overdrive. The idlers do not effect the rate at which other accessories are driven nor are they being "driven" (i.e., they're not connected to an accessory). Using different sized idlers can however effect the belt tension and depending on how much they differ, they could require using a different belt size altogether.

[red]

I changed the alternator already and it still does the same thing, which means the clutch wouldnt be the problem. and its idling around 700 rpms.
So, you've done pumps (water and power steering), alternator, tensioner, belt, and at least on the idler pulleys. And still a noise, plus low voltage. Have you had your FLAPS check the new alternator? As you suggest, it could be the harness. Have you checked for corroded connections? Have you checked the ground cables?

[dankwun]

no i havent had the alternator checked, thats another thing i was planning on doing. as for the grounds, i ran a zero guage ground to the block and a 2 guage to the body. i am missing the ground that goes to the frame though, is that one ground really that important? do you happen to know what the wires that go to the harness are for? is one of them the wire that tells the alt when to start chaging?

[FordNut]

i am missing the ground that goes to the frame though, is that one ground really that important? do you happen to know what the wires that go to the harness are for? is one of them the wire that tells the alt when to start chaging?

Yes
Yes
Yes

[red]

I agree with FordNut. See the diagrams here (http://www.mercurymarauder.net/forums/showpost.php?p=653248).

[dankwun]

thanks.. i just changed the smooth pully and its still making the noise. so i revved the engine to try to pin point where it is coming from and it sounds like its coming from the alt. when i rev it and keep it steady at a certain rpm it makes this grinding sound. would that be the sound of the clutch going bad?also do you happen to know how many volts are supposed to be running through the wires for the alt harness?

[red]

thanks.. i just changed the smooth pully and its still making the noise. so i revved the engine to try to pin point where it is coming from and it sounds like its coming from the alt. when i rev it and keep it steady at a certain rpm it makes this grinding sound. would that be the sound of the clutch going bad?also do you happen to know how many volts are supposed to be running through the wires for the alt harness?
I don't know about the grinding, but it probably isn't good. You might have another bad alternator. Did you go with an OEM replacement? Concerning the voltage, the PCM serves as the regulator. Generally, your charging system will run a couple volts higher than the battery voltage, which is ~12 V, as you should see on the voltmeter gauge, but this can vary based on how the PCM is regulating the alternator output. Be careful how you test the alternator. I'd swing it by your FLAPS and have them test it for free.

[dankwun]

no i didnt replace it with a oem alt, i replaced it with a high output 200 amp alt. but now that i think about it when i bought it it said that it puts out 200 amps at 1100rpm. maybe the regulator inside the alt doesnt allow it to start charing until around 1100 rpm. im not too sure on how it works, but is this a possibility?

[Marauderjack]

1100 RPM's of the alternator shaft....with the pulley size difference I'd think the alternator turns 3x the crank??:cool:

I would go and get an OEM alternator....too many folks have had problems with after market units!!:argue:

[red]

I would go and get an OEM alternator....too many folks have had problems with after market units
I agree that you should use an OEM unless you absolutely require this output.

[dankwun]

i took my alt to two different place and they couldnt test it. and i changed both idler pully's and its still making the noise. i noticed that the power steering pump pully can be pushed in and out or wiggles a little.. is this normal?

[red]

i took my alt to two different place and they couldnt test it.
Why? What'd they say?


i noticed that the power steering pump pully can be pushed in and out or wiggles a little.. is this normal?
I don't know if it's normal, but I seem to recall mine having a little play the last time I had the belt off.

[dankwun]

pepboys said that they didnt sell the part and the test machine couldnt take the code to test it and advance said the alt wouldnt fit on the tester..

[ctrlraven]

When I bought my car I had a low charge alt. Took it back to the dealership and they replaced it with a new FoMoCo unit. The stock unit would charge around 12.5-12.7 at idle with nothing on. Replaced the unit and now normal range is 13.9-14.0 with lights, radio, etc on.

When in doubt replace with OEM first.

[dankwun]

ok.. i guess im gonna get an OEM alt and see what happens..

[dankwun]

what other pullys are known to go bad and would cause the wining noise?

[red]

ok.. i guess im gonna get an OEM alt and see what happens..
As previously stated, I agree with the others on using the OEM alternator. Post back once it's installed.

[red]

what other pullys are known to go bad and would cause the wining noise?
You've replaced nearly everything (belt, idler pulleys, tensioner, alternator, water pump, and power steering pump). The A/C compressor is the only thing left that I can think of. I'd recommend putting the new OEM alternator in before tackling anything else. Hopefully this will get you past the low voltage issue and possibly resolve the noise issue!

[dankwun]

i put the oem alt on and it fixed the volts problem a little and the noise is still there..i dont know what to do now..

[Marauderjack]

I had a noisy "Smooth" idler that I swore was the ProCharger.....rough bearing and it roared.....maybe that one is your culprit??:confused:

Marauderjack:burnout:

[dankwun]

i changed both idler pullys already..

[Marauderjack]

Go to CarQuest and get a mechanic's stethoscope to isolate your noise....hope it's not internal!!:shake:

Marauderjack:bandit:

[red]

Concerning MarauderJack's comment, have you been able to isolate the noise to a certain part of the motor? Under what conditions does it happen or does it occur all the time? As I see it, you have A/C compressor, possibly the fan (though it should only run as necessary), and worst case, internals. Can anyone think of something not already mentioned above?

[Marauderjack]

My idler ended up being the culprit but it sounded like the "growl" was in the passenger side head......sounds are transmitted quite a distance through metal!!:cool:

You only have 2 idlers, 1 tensioner, alternator, water pump, PS pump (unlikely) and AC compressor on the front of the motor.....if it ain't one of these it must be internal??:confused:

Can you get a sound clip or video to post up??

Marauderjack :burnout:

PS: Glad the alternator is working now!!:beer:

[red]

You only have 2 idlers, 1 tensioner, alternator, water pump, PS pump (unlikely) and AC compressor on the front of the motor.....if it ain't one of these it must be internal?
And he's replaced all these! Only other thing I could think of was the electric fan (it rotates), but that would only occur [obviously] when it's on. Any other ideas? Please do post up clips of the sound.

[dankwun]

http://i73.photobucket.com/albums/i229/dankwun/th_MVI_1939.jpg (http://www.mercurymarauder.net/forums/newreply.php?do=newreply&noquote=1&p=660877)

[dankwun]

i noticed that the sound changes when i turn the a/c on.

[Marauderjack]

i noticed that the sound changes when i turn the a/c on.

Sounds like a bad bearing and the A/C just loads it more so there will be a sound change!!:confused:

Remove the belt and start it and see if the sound is there.....if not, you have to isolate which pulley is doing it or the water pump, A/C, alternator or PS pump!!:help: If it is there without the belt it has to be internal but I don't think it sounds like it is internal.:shake:

Marauderjack:burnout:

[red]

Just confirming: you've replaced everything touching the belt minus the A/C compressor, right? Does this include all the pulleys (ignoring the crank pulley)?

[dankwun]

no.. i only changed the water and power steering pumps, not the pullys.

[Marauderjack]

Idlers and possibly tensioner then......take the dang belt off and see what happens when you start it!!:rolleyes:

After you find it to be quiet without the belt.....spin each of the pulleys and tensioner and I'll bet you find one of them rough!!:cool:

[red]

Idlers and possibly tensioner then......
In previous posts, he said he already did these.

[Marauderjack]

no.. i only changed the water and power steering pumps, not the pullys.

Red,

I thought he said he already replaced them all but in the quote above he says no???:confused:

Is he messing with us??:rolleyes:

Get a stethoscope or a dowel rod and listen to the pulleys....REPLACE the noisy one and be done with it!!:bandit:

Also.....make up your mind what you have already done.....we are trying to help you here!!!:beer:

Marauderjack:shake:

[red]

no.. i only changed the water and power steering pumps, not the pullys.


I thought he said he already replaced them all but in the quote above he says no?
Ah... I took his statement to mean that for the pump replacements he only swapped the pump itself and reused the stock pulleys.


Is he messing with us?
I guess he should post a full list of everything he's done or not done for clarification.