Astra electical issue

Hi folks.

I have a 2000 Astra LS 1.7 DTi which seems to have a minor electrical
problem that I've seen twice before.

When I start the car from cold and let it idle, the brightness of all
lighting (both exterior lights and dash illumination) pulsates in time with
a slight variation in engine pitch/speed. If I increase the revs, this
pulsating speeds up and then disappears at around 2000 rpm. The pulsating
doesn't happen after the car has been driven for a while and is fully warmed
up.

Also, when the car is cold, there's quite a large difference in light
brightness when idling the engine and when reving it up to about 2k, much
more than is normal. I don't have any problems starting the car, nor do I
ever see the dash battery light come on after the engine starts. It's the
original battery that was supplied with the car, so it is just over 6 years
old.

When the car last had the problem, I believe it was fixed by replacing the
entire alternator. At the time the car was owned by a fleet company so I
didn't have to foot the bill. Now that I own the car, I'd like to
investigate lower cost remedies before splashing out on a new alternator.

When I've asked about this problem before, I seem to recall some mention of
a voltage regulator on the alternator that may have deteriorated. Is this a
common problem, and if so can this regulator be replaced without changing
the whole
alternator? Where would I be able to obtain the necessary part? How easy
would it be for someone with basic tools and mechanical skills to replace?

Any advice much appreciated.

Jase

 

The voltage regulator is a valid point of enquiry, but get your battery
checked out at a battery place anyhow, as they will usually do it for free,
and probably check your charging voltage as well. is it a sealed battery, or
can you check the electrolyte in the cells?

Mike

 

yes you can change the 'regulator' block
thats what all the refurbish places do
easy as such to do and to get ahold of.

id change the battery first
and check the idle and its control mechanism is set up properly before that
though.

mike

 

Thanks for the replies Mike(s).

It's a sealed battery.

I just popped down to Kwik-fit and they popped a meter on it. While the
ignition was off, the battery supplied a steady 13.8 volts. Once the engine
was started and some electrical load was applied (headlight main beams), it
was constantly fluctuating between about 13.8 and 14.3 volts.

This seems to rule out the battery being at fault and reinforces the
possibility that the alternator or voltage regulator is dodgy.

Would the voltage regulator be built into the alternator, or is it a module
clipped on the side that can be removed and replaced? Who is a likely
supplier of a replacement?

Thanks.

Jason

 

Afraid I cant help you on that score, but at least Youve eliminated the easy
option.

Mike

 

well TBH that tells the charging circuit is working
thus the alternator is OK

if a cell is going down, it just wont hold/deliver the current
the volts will be a bit higher & the battery will appears to charge.
but charge very quick [interims of voltage readings]


a discharge tester is what you need not a multimeter


ok so be it...

the rectifier/regulator module is internal to the alternator
though they can [and are when refurbished] replaced.
that's what these exchange alternator people do.

I would thing a quick search on eBay or Google for say
alternator regulator pack or something
should throw up some ans.

if you are electronically minded, you can even crack then open ond change
the diodes/regulator yourself

mike