Just had a new alternator fitted and car now feels very sluggish!

[spbs]

I have a c200 coupe 2003 the new alternator was installed, my car picked up speed fast; but now it is very sluggish and slow.

Why could this be?

Thanks in advance for your advice.

 

[dozypillock]

You may need to post more information, as a seriously doubt the alternator can cause this?
Why was alternator replaced? What problems did car have to cause this? What errors were you getting?
The more info you can give, the more chance you may get help.

Neil

 

[spbs]

Thanks Neil.

So, I have had the year for 3 years, drove excellent. About 2 months ago the SRS light popped up on my dash along with "battery/alternator visit workshop". It then didn't appear for about 3 weeks.

They came on again, but constantly stayed on everyday. Eventually my headlights became dim etc and while driving the car cut out with all the electrics faintly on.
I did jump start it as I thought initially was battery but few yards into driving same again.

I took it to garage and he advised me the alternator wasn't sending a charge to the battery. (When the battery was tested had 4v). Consequently, brand new alternator fitted.

The car just doesn't seem to drive as it did. Doesn't have the power it did, I feel. I just hoped the alternated needed to 'wear in', but a week on no improvement.

Thanks

 

[Giantvanman]

When the alternator was fitted, was the existing battery tested and given a good charge from an external charger?

 

[spbs]

I'm not too sure, but when I collected the car he tested the battery, advising it was charging- it was showing at 12v+. Not sure if externally charged.

 

[Giantvanman]

Bearing in mind the battery was drained because the original alternator was faulty, the new alternator will try to charge it but it will not always be able to fully charge the battery. There is also the possibility that either A. the battery is also defective B. the alternator change will have meant the battery being disconnected and if not done correctly, other problems could surface electrical wise and C. the problem with sluggishness is unrelated entirely.

It is a process of elimination. 12+volts; is that output from the alternator or what the battery is reading on test? Was the error code(s) cleared after the work was done? etc etc.

BUT and alternator doesn't need time to run in. It works or doesn't work.

 

[DSM10000]

I'm not too sure, but when I collected the car he tested the battery, advising it was charging- it was showing at 12v+. Not sure if externally charged.

A healthy battery supplied by a healthy alternator should be showing around 14.4V at idle with no load.

 

[dozypillock]

I'm not too sure, but when I collected the car he tested the battery, advising it was charging- it was showing at 12v+. Not sure if externally charged.

Is it safe to assume this was NOT a Mercedes dealer, or even an "indie" and just some local garage?
Did they disconnect and reconnect new battery, whilst maintaining power?
Were any codes checked, or have they been since? Even a cheap OBDII reader from ebay can help if you have never seen the codes etc
Worth buying one? I would say. Spend a bit more and get a better one.
12v is wrong with engine running, unless you have a serious amount of extras running. As somebody else pointed out, 14.4v is more normal, and even when loaded, should still run much higher than 12V or it will not charge.
Unless it is still dropping down to 4V I cannot see how alternator will really affect performance that much.

Neil

 

[spbs]

It was the Halfords auto centre garage, I would hope they would do it correctly? As you describe!

So, sounds like there is no correlation between the new alternator and sluggishness?

 

[sharps]

you should get the fault codes read on it

 

[spbs]

One thing I did forget to mention is that my car is consuming a lot more fuel than before. Why could this be? What could I do to check?

 

[moonloops]

It was the Halfords auto centre garage, I would hope they would do it correctly? As you describe!?

OOF!

Have you checked that all four wheels are spinning free and no brakes are binding on slightly may be a coincidental problem that has occurred at the same time?

 

[spbs]

OOF! Have you checked that all four wheels are spinning free and no brakes are binding on slightly may be a coincidental problem that has occurred at the same time?

Sorry?

 

[NDFR]

Sorry?

You have a nice car but take it to Halfrauds and still have problems.

You need to be visiting a good Indi

 

[geraldrobins]

It seems you need to take it back to Halfords initially and obtain their comments as there may be a simple reason and remedy.