Vauxhall Astra F (1991 - 1998) - 1997 TDS (isuzu) - rev counter

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Sun 2 Dec 2007 19:54
1997 TDS (isuzu) - rev counter - brunton_pasty
Some very wet roads on Friday night seem to have gotten to the alternator, first sign of which was the rev counter dropping to Zero as I believe thats how the revcounter is driven. Measured the voltage across the battery with the engine running and it was struggling to get much above 12.5 volts. Even when the engine was revved hard the voltage only crept up by about 0.1 of a volt. With everything off and the keys out of the ignition it was still reading about 12.5 volts.

I managed to do 250 motorway miles today with lights on, at the end of the journey still getting 12.5 volts across the battery with the engine running. So the alternator seems to be working to some degree, but something is still definitely up.

With the engine running shouldn't I be getting about 13.5 volts across the battery?

Could this be caused by V drive belt being loose? (seems ok to my very untrained eye)
Or any other suggestions i.e. I've fried some component in the alternator with all the water?

Any help much appreciated.

Edited by Webmaster on 02/12/2007 at 22:53

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Sun 2 Dec 2007 20:13
Vauxhall Astra F 97 TDS (isuzu) rev counter - Screwloose
bp

That's a very complex control system on that alternator. Be very careful, as mistakes can be either costly or disastrous - I've had two burn the car out when the charge-light relay catches fire under the dash. [In one case when someone had told them it just needed a new one.....]

Check the output cable [the thick one] for an in-line joiner about 18" from the alternator. It may not be fitted on that year; but if it is, they corrode. Also check the 4-way joiner for the sensing and control circuits for corrosion and broken wires.

Anything more than that needs an autoelectrician, as these are too Heath-Robinson for amateur testing.
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Sun 2 Dec 2007 21:17
Vauxhall Astra F 97 TDS (isuzu) rev counter - elekie&a/c doctor
A very poor design on these with the alternator mounted very low down at the front of the engine with no protection from the elements/salt/corrosion.Definitely worth getting the belt tension checked as a loose belt on these does not often squeal as a larger vee section type is used.Also adjustment of the belt can be a bit tricky as it has to be done in conjunction with the power steering belt (if fitted).hth
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Sun 2 Dec 2007 21:56
Vauxhall Astra F 97 TDS (isuzu) rev counter - injection doc
Take screwlose advice & get expert help. Don't go for a cheap alternator if it proves to be at fault. His advice is spot on so tread carefully
Doc
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Mon 3 Dec 2007 16:29
Vauxhall Astra F 97 TDS (isuzu) rev counter - brunton_pasty
Checked the connections, still nothing doing.

Took it to my normal garage and they've put a new alternator on. Now getting a healty 14Volts across the battery.

I agree with the comment about it's exposed position, I hope thats a lesson thats been learned on the newer models.

Thanks for the advice
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