Rev Counter.

[Dave_H]

Hi All, When parked up and the ignition off, the rev counter on my S3 just sits below 1500 rpm. But turn the key on the ignition it goes back to zero before cranking the engine and behaving normally. This to me points to an electrical fault, or do they all do this? Any one else experience this? Cheers, Dave.

[johno]

Dave, Mine does sit below the zero when the ignition is off. The speedo however goes all over the place ! I don't and wouldn't - if I were you - about it as long as they are reading correctly. Both off mine have been checked when on a rolling road and there was no issue so I forget about it. Cheers Mark

[BurdeG]

My rev counter & speedo act in similar ways, basically due to them being electronic, when no power goes to them, they 'rest' and gravity sometimes means they drop a little - NOT A FAULT of the car. I recently had mine tested & re-bezzled at speedy cables and after all there tests showed 100% ok, they still act the same as yours. Giles

[RichB]

Yep sounds like "they all do that sir" I remeber my speedo would sit at around 30 when off and the rev counter sat at around 2,500.

[Dave_H]

Cheers Guys, The gravity explanation makes perfect sense now -D'oh! Regards, Dave.

[LeeBee]

Mine doesn't , but lots of them do! Cheers LeeBee

[macwalsh]

Mine does the self same thing. Turn off the engine - rev counter sits at 1000. Another thing re the speedos, when starting up and the charge light stays on (until hitting around 2200 rpm which kicks in the charging circuit I believe) the speedo can read anything up to 70mph, and I'm not even out of first gear. Its quite wierd when the charging system cuts in and, even though the car is accelerating, the speedo needles drops backwards to the correct speed. Cheers Andy

[Dave_H]

quote:Mine does the self same thing. Turn off the engine - rev counter sits at 1000. Another thing re the speedos, when starting up and the charge light stays on (until hitting around 2200 rpm which kicks in the charging circuit I believe) the speedo can read anything up to 70mph, and I'm not even out of first gear. Its quite wierd when the charging system cuts in and, even though the car is accelerating, the speedo needles drops backwards to the correct speed. Cheers Andy

But hey, arnt they fun!!! Several people have said the same about the needles,all part of owning a tiv, and the battery charging thing is fine, they are meant to do that. I've just had my first full day buzzing round in mine Thanks for all the replys guys.

[Greenv8s]

quote:Another thing re the speedos, when starting up and the charge light stays on (until hitting around 2200 rpm which kicks in the charging circuit I believe) the speedo can read anything up to 70mph, and I'm not even out of first gear. Its quite wierd when the charging system cuts in and, even though the car is accelerating, the speedo needles drops backwards to the correct speed. Cheers Andy

The alternator field coils have to be energised in order for the alternator to generate power. Once the alternator is energised it powers the field coils itself. The problem of course is that until it has to be energised in the first place. The no-charge warning light feeds a small current through the coil which does this. The revs it takes for the alternator to 'kick in' depends on how much current the no-charge warning light feeds it. If the bulb fails the alternator can sometimes be energised by using the residual magnetism of the coils, but this takes a lot more revs. On my S2 I used to have to rev it to about 2000 rpm to kick-start the alternator. On the V8S it kicks in at about 1500 rpm. Being a V8S it is pre-serpentine, non-PAS. Other cars may have a different gearing and need different revs to get it sytarted. The V8S engine usually revs high enough on startup to get the alternator going, if it doesn't I would rev the engine to get it charging before switching on lights etc and driving off. Cheers, Peter Humphries (and a green V8S)

[macwalsh]

Thanks for the tip Peter - I quite often take the car in to work which necessitates firing it up at about 6 AM. Next door has already made a couple of references to the noise (she's not a car enthusiast)- now I have a perfectly valid excuse for giving it an extra blast before I drive off at the crack of dawn. Cheers Andy Edited by macwalsh on Monday 24th September 22:06