matrix11229

My alternator was replaced by mechanic last week.
He told me that he didn't apply too much tension on the belts, he said it's better this way.

But now I feel a slight vibration in idle and the rpm gauge arrow goes up and down a little bit in idle (P or N). It jumps approximately 50 rpm up and down.
I feel the vibration in the steering wheel , seats...everywhere.
When I shift to D it vibrates even more.

I didn't have that vibration before.

Could it be due to not enough tension on the belts ?
Also my horn sounds weak now, not a usual sound.

I have no idea what's going on and that vibration is killing me, I can feel it even when I drive 30mph(I feel this vibration under my butt and it's very annoying) .

sam29281

lol, he fud on the installation...it's not giving you enough juice. Tighten it.

JFP in PA

My 97 SE was subject to a factory alternator recall 2-3 years back, Nissan put in a brand new replacement unit that vibrated and howled like Hell........took it back and they put in another new unit, which has been silent ever since....................could be the unit...........

Black Maxima

Is the alternator shaking at all? He possibly didn't tighten the bolts good enough.

matrix11229

I'm gonna check if it vibrates
But what do you think is the cause of the jumpy idle ?

sam29281

the alternator provides the juice to the battery and all other components... You could say that the sparks could be running from the battery but the alternator is the main source. It could throw off the ecu and cause the jumpiness.

Apparition

iTrader: (5)

why does this make me wonder..............about our other vibration thread. maybe it really is the alty, but why would the vibration go away after the car is warm?

Black Maxima

I have a new alternator and I still get the noise. I think my engine harness is screwy or I have a bad chargeing system. If I leave my radio on long enough without the car running, I will need a jump.

matrix11229

In my case the vibration is constant and doesn't go away when the car is warm.

Apparition

iTrader: (5)

oh alright, makes sense..

JEXTEL

iTrader: (2)

My does the same thing with a Brand New alternator and only puts out 13.7(AM)compare to 14.1(OEM). Plus my new alternator is 125 amp and the stock one is 110 amp weird huh?

matrix11229

I checked the alternator with a screw driver and it doesn't vibrate at all.
The engine itself is vibrating.
I guess it could be the belts tension.

I went to the mechanic but they were busy so he said to come back tomorrow.

matrix11229

I went to my mechanic today to check the cause of constant vibration, and now I have a feeling they f**ked up something in my car when I left it there for a day.

The boss told me that the vibration is not related to the alternator and they are not gonna even look at my car because they are busy !?.
So I asked how come I didn't have that vibration before they worked on my car ?
And he said - I didn't do anything to your car and we have no time checking it now.
So we started arguing and I said I'm gonna sue him. Finally one of his partners agreed to just "take a look", so he checked the belts tension and it was ok, and he sat in the car and felt the vibration, so he said it's not the alternator it's probably "something else".

They told me to come back on Saturday and they gonna put it on a lift and then they will tell me if they gonna fix it for free or there are other problems that I will have to pay for fixing them !

So now I'm really pi$$ed off, the car vibrates constantly when it sits or rides and everything vibrates even in Neutral : steering wheel, pedals , seats, arm rests. Also the Rpm gauge arrow moves up & down in N. It's very uncomfortable to drive like that and it's hard tolerate this vibration for more than a 10 min short trip.

I don't know what could they do to my car ? Could they replace the fuel pump with a defective one or coilpacks or some other parts ?
What could be the cause of that constant vibration ? (the alternator doesn't shake)

JFP in PA

You need to take the car to someone credible and not involved todate. Your "wrench" sounds like a real mutton head to me........................

matrix11229

I went there today and 5 mechanics all together were checking my car and didn't find the cause of vibration. They said "everything look ok, may be sometimes later the vibration will get worse, then we will be able to find the reason". Also they checked the volts and it makes 14.1 even with lights and defroster on.

I don't know what to do. Besides alternator they replaced rear O2 sensor that I bought on ebay(bosch) and I replaced coolant temp sensor by myself the same day last week(bought it at the dealership despite that my old sensor was working).

So I'm thinking of 3 causes of the vibration:
1) The alternator
2) coolant temp sensor
3) They did something to my car(replaced some parts with defective ones)

Any Ideas ?

JFP in PA

For the love of Christ, take the car to someone else!

matrix11229

I took the car to another repair shop and they told me that "the alternator couldn't cause that vibration ,so the problem is in something else and it will be very hard to find".

So I asked him to disconnect the alternator from the electrical harness to see if the car vibrates with alternator turned off, but he said it's not gonna help.

This constant vibration is pissing me off, I can't take it for a long time.

Did anyone else have vibration after alternator replacement and how did you fix it ?

JFP in PA

When I had a brand new factory unit that was bad, the only thing that stopped the vibration was to replace it...........then it stopped immedeately. Disconnecting power to it will do nothing if the vibration is bearing related, as mine was............

sam29281

you should check out the repair manuel on this thread. Find electrical...find alternator. Unplug it and see for yourself. It will be running off of battery so don't keep it running. Just find out and on to the next.

matrix11229

Can you explain how bad was the vibration and where it could be felt ?
What exactly vibrated in your car (the alternator or the whole engine) ?

In my case the alternator itself doesn't vibrate, it's the whole engine that vibrates and I can feel it even in the drivers seat.

I can buy Hitachi Nissan 110 amp remanufactured alternator at ebay but I don't know if it will fix the problem if the mechanic replaced some parts with defective ones.
I asked the ebay seller about my vibration and he said he never heard of those problems(he has 100% positive feedback on his products, he sells alternators and starters only).

JFP in PA

Just to set the facts straight: In my case, Nissan pulled out the original unit under a factory recall, replacing it with a brand new factory unit. This unit casued a low rumbling buzz felt inside the car, particularly when cold, along with a high pitched whine under the hood that got worse with time. When I took the car back, they argreed that the unit was causing the problems and replaced it with another brand new factory unit, which has been silent ever since. The unit that cased the issues would produce a slight sound and vibration when turned by hand................... If I were you, I'd pull the belt off and turn the unit by hand while still on the car, looking for excessive drag or vibration. If a new unit can be bad, I'm sure a rebuilt or used one could as well.........................

98MaximaEcstasy

iTrader: (3)

I'm just throwing this in but my friends altima had this crazy vibration and we couldn't find anything at first. Later on when we had it on the lift and we realize the engine mounts were shot.

I guess it wouldn't hurt to have a look at those...

matrix11229

Engine mounts are ok. The vibration appeared immediately after alternator replacement so most likely it's the alternator.

matrix11229

Finally I replaced the alternator with the one from ebay. I went to my mechanic and he gave me money back for the alternator and replaced the alternator for free.
I still feel vibration in N / P / D / R, not as strong as it used to vibrate but I can feel it in the steering wheel.

What could the mechanic do wrong or cut some wire that could cause the vibration ? May be he replaced some parts with defective ones ?
I have no CEL and my spark plugs are new (NGK copper), I took couple of plugs out and they look fine.
I'm so frustrated that I just wanna sell my car.

maximamaxy

Does the vibration ease a little in P and N compared to D? Can you feel the vibration on any of the pedals? If you rev it to about 1k rpm does the vibration decrease?

matrix11229

Yes ,the vibration ease a little in P and N compared to D. With the first alternator they put in I felt vibration in the pedals and everywhere in the car, but with the second alternator I feel it only in the steering wheel and door handles while the car sits in N or P. I didn't check if it vibrates in P when I rev it (I'm gonna check it today) but I think I could feel some vibration in the steering wheel when I drive.

matrix11229

I checked the Idling today; I rev it to about 2k in P and the vibration got much weaker at high rpm. The vibration is stronger in the 700 - 1300 rpm range.
I checked the spark plugs and they are ok (brand new, 2 months old).
I think the vibration feels like when I put bosch platinum+2 plugs but since I put Ngk coppers the engine was running smooth.

What could the mechanic do wrong/brake during the alternator replacement ?

rocco5446

iTrader: (2)

Could be he didn't set the proper tension on the belts, or even properly tighten the idler pulley, even though they claimed that the tension is good when you took it back. I recently had my belts changed, and I think my mechanic may have over tightened the belt, so I took it upon myself to loosen it a bit and noticed that the engine revved more smoothly and idled better when I had loosened it up. But then I ended up loosening it too much and ended up getting some vibrations at idle and low rpms while cruising. I finally ended up setting the tension where the belts make a really short squeal at start up, then tightening the tension by turning the idler adjuster by one full turn, which then eliminates the squeal at start up, without over tightening the belt. Things have been super smooth since. Worth a shot, at least.

matrix11229

Thanks Rocco, I guess belt tension is my problem.

How do you adjust the tension ? I see there is a long adjusting nut over the idler pulley but there is a writing on him -"tighten after adjustment". So how do you move the idler pulley to adjust the tension ?