57 replies to this topic

[VXTyrant]

Hi guys. I've been leaving my VX on charge (Ctek XS3600) whilst not in use, usually for one night every few days, to make sure the battery is topped up. However, after a day or two's use I'm noticing that the car will struggle to start as though it hasn't much power, but will then fire up. I use it to commute and that is enough distance that it should be charging up on the alternator with no problems. What makes me think the alternator may be an issue is a post by DarrylB in a separate thread:

Hmmm I'd start by checking the alternator is supplying the right voltage. I had an alternator fail on my old Astra and it was dishing out 19.8v and plenty of smoke! Caused the power steering to fail which was fun with 5 in the car.

The reason I think this is that mine is giving off white smoke out of the rear drivers side boot vent every now and then. Any thoughts on this or tips on how to test the alternator?

Edited by VXTyrant, 09 March 2012 - 10:08 PM.

[techieboy]

Have you got a Scangauge? That'll tell you what the voltage in the car is, with the engine off and the engine running.

[VXTyrant]

Have you got a Scangauge? That'll tell you what the voltage in the car is, with the engine off and the engine running.

I haven't but I have been meaning to look into getting one of these. Which one is recommended for the VX and where do most people buy them from?!

[GiGo]

My battery kept on dieing and it turned out to be the tentioner for the belt, got that sorted along with a new belt and it's all ok now

[ghand]

Can you get hold of a volt meter. 12v off and about 14/14.5v running. If its over that when running the voltage regulator in the alternator is goosed which is not good for your electrics . But you may get more volume from the cd player

[turbobob]

Can you get hold of a volt meter.

12v off and about 14/14.5v running. If its over that when running the voltage regulator in the alternator is goosed

which is not good for your electrics .

But you may get more volume from the cd player

Although I'd say down to 13.5 is probably still ok.

[VXTyrant]

I've ordered myself a Scanguage II and, based upon the delivery info, it a should be with me by Monday so I should have some solid results to post in the very near future

[turbobob]

If it's not too late a cheaper alternative is a Bluetooth obd connector and torque. Application on your phone. The whole lot costs 20 quid.

[VXTyrant]

If it's not too late a cheaper alternative is a Bluetooth obd connector and torque. Application on your phone. The whole lot costs 20 quid.

I've wanted a Scanguage for a while anyhoo so this was probably the excuse I needed

[VXTyrant]

Thinking the alternator must be shagged! Plugged my new Scanguage II into the car this morn on the way to work. No fault codes but voltage was reading around 12.2 with ignition on and dropped to around 11.8/9 by the end of my journey (engine on). On the way home the voltage is going down (now 11.6). Plugged it into my CTEK and will do the same on tomorrows commute but it definitely seems like the alternator isn't charging the battery (which I replaced for a Bosch S5001 at the weekend)! Anyone else think the alternator is the culprit and, if so, is it a pita to replace?!

[turbobob]

No that I'm knocking the scangauge, but using it to read what the ecu thinks the voltage is when you are having an issue would just make me to want to take a proper reading with a voltmeter. That said it sounds like your car has just been running off the battery as it has gone from 12.2 to 11.6v. So I would want to check the continuity between the alternator and the battery. If you have fitted a new alternator that makes me suspicious that there is a break somewhere.

Edited by turbobob, 20 March 2012 - 06:34 PM.

[VXTyrant]

No that I'm knocking the scangauge, but using it to read what the ecu thinks the voltage is when you are having an issue would just make me to want to take a proper reading with a voltmeter.

That said it sounds like your car has just been running off the battery as it has gone from 12.2 to 11.6v. So I would want to check the continuity between the alternator and the battery. If you have fitted a new alternator that makes me suspicious that there is a break somewhere.

I haven't fitted a new alternator, I've fitted a new battery. What checks would you suggest?

[turbobob]

Sorry I misread that. Try and get your hands on a mutlimeter. Then with the engine running check the voltage on the battery terminals with the multimeter. This should be 13.5 to 14.5v. If itz not kill the engine. Next (I haven't checked the schematics all there could be a fuse or relay and I ask other vx'ers if this is the case) attach a length of wire to either the positive battery terminal or the positive terminal of the alternator then using the mutineer set to resistance, measure the resistance between the positive terminal of the battery and the alternator. If OK repeat for the ground terminal. Failing that I suspect your alternator is fcuked.

[ghand]

Funny one,if you only have 11.6v at the battery with the engine running its not charging the battery right.So the red warning light should be on telling you its not. May be the alternator is giving an output ok,putting the light off but not getting the connection to the battery to charge it ? What do you reckon Bob

Edited by ghand, 20 March 2012 - 09:31 PM.

[turbobob]

Quite possibly. Which is why I would check with a meter both the voltage on the battery with the engine running and the resistance between the alternator and battery. Should give a good indication whether there is a break or not.

[rob999]

Are you getting the lovely battery light on the dash on start up?

[ghand]

Quite possibly. Which is why I would check with a meter both the voltage on the battery with the engine running and the resistance between the alternator and battery. Should give a good indication whether there is a break or not.

Thats a plan,on a "normal car" you would just go direct onto the alternator to check its running output voltage

You cant even see it on the vx :lol;

so where is the first port of call the output will go you can get a meter on.Fuse box ? or is it a direct cable to the battery ?

[ghand]

Are you getting the lovely battery light on the dash on start up?

Better not be as that just tells you the alternator is shagged and we need go no further

[VXTyrant]

Are you getting the lovely battery light on the dash on start up?

Better not be as that just tells you the alternator is shagged and we need go no further

Would this light go out after the key is initialy turned (like most of the lights do after around 5 seconds) or would the battery light stay on permanently?!

Edited by VXTyrant, 21 March 2012 - 12:10 PM.

[Nev]

Swapping the alternator is not easy. On mine the main bolt was impossible to get to and impossible to extract as it was so long I couldn't draw it out becuase it fouled something. Check first that your alternator is making charge by putting a circuit tester on it's outpur terminal. If it is, then check that the earth is good. Then check your battery is also receiveing charge.