alternator(im thinking)

[King_berald]

gday fellas.....as most of you have probably read 100 times...my vp has a slightly rough idol....have no idea what the hell the problem is....tried soo many things but still no success...

now....i noticed that when i drive at night with my headlights on, its slightly worse....and with the high beams on...its even worse yet.....
im thinking the problem could be to do with the alternator now...

how plausable is this? and also how do i test an alternator?

thanks

[leigh 7005]

easy way to test is take your battery leads off when car is running if it stalls alt is stuffed if keeps running should be ok but my misuses car battery kept going flat took the leads off and it was running still but the alt was still stuffed

[delcowizzid]

pulling the battery leads of when running is the easiest way to kill an alternator use a volt meter and make sure its pumping out the correct voltage.

[Noy]

Test it with a multimeter, think it should read around 14 volts for a full charged battery

[vsl67]

sounds like your earth points are faulty or dirty

[VrWagz1]

I very much doubt the alternator is the cause. As you say when the lights are on the knock may get worse due to the alternator becoming hard for the engine to turn when your drawing 20 or more amps out of it. Sounds more like dodgy spark, be it dfi, coils, leads or plugs.

[King_berald]

well i tested the battery terminals yesterday with the car running at about 2000rpm....and i was getting 14.12.....looked in the gregories and its supposed to be up at about 14.25-14.55....so i took the belt off and spun the alternator pulley to listen to the bearings....and they are also making a slight noise...is this anything to worry about???

also just so you know...ive pretty much replaced everything from sparkies, leads, injectors to things like fuel pump, battery, etc etc....

[pjdm1980]

If your a running a big amp, subs you could be using to much power and your need to upgrade your battery and/or alternator but shouldn't make for ruff idle.
Have you had the O2 sensors checked you can tell some times buy looking at your plugs if one bank of plugs is black and the other is clean and your probably using more fuel than usual!

[King_berald]

If your a running a big amp, subs you could be using to much power and your need to upgrade your battery and/or alternator but shouldn't make for ruff idle.
Have you had the O2 sensors checked you can tell some times buy looking at your plugs if one bank of plugs is black and the other is clean and your probably using more fuel than usual!

oh ok....what would be the likely problem for the headlights making the engine run rougher?

also i realisedthat with the headlights on...they dim when u use the horn...

[delcowizzid]

check the battery volts with it running with all the extra accessories you have turned on high beem lights heater fan etc