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        General >> Problems >> Possible faulty alternator?
        
(Message started by: RichKavanagh on Apr 30^th, 2011, 3:40pm)

Title: Possible faulty alternator?
Post by RichKavanagh on Apr 30^th, 2011, 3:40pm

Ford Scorpio Ultima 1995 2.9 16v

Hi all,

I'm wondering if you can shed some light on a problem my Scorpio has recently developed.

Whilst driving recently the entire dashboard went out. Needles dropped to zero, lcd displays went blank, as if the whole thing had been unplugged. Also at the same time, the electric windows stopped working (didn't check anything else, was driving at the time). The car was still driving fine though, just no dash and no windows.

A few minutes later, the dash came back to life on it's own (and the windows started working again) but the rev counter sat on zero. Everything else appeared to be working fine.

Since then though the battery light has been on all the time and the rev counter sits at zero all the time unless you rev the engine above 3k, then the rev counter springs in to life (but the battery light stays on). If you idle the engine or take your foot off the throttle the rev counter drops to zero again.

I've tried a few things, like checking the multiplug from the engine to the main loom (the one with the bolt head on the top of it) and I've swapped various relays in and out and checked the obvious fuses.

Today I put a multimeter on the thick red cable that comes out of the alternator to see if I could spot anything. I connected the multimeter up with the engine off and it read 11.9v (the same as the battery reading at the time). I left the meter connected and started the car. As I rev'd the engine I would have expected to see the voltage go up with the revs but it stayed on a rock steady 11.9v constantly.

So two questions really:

1) Was I checking the alternator the correct way, should I have put my meter on to a different wire?

2) Assuming I've checked it correctly, can you confirm that as I rev the engine the volts should have gone up with the revs?

If so, I guess I'm looking at a faulty alternator.

However, before I chop it in for a reconditioned one is there anything else that I can check or look for before spending some cash?

I was wondering with the whole dash going out, could it be a bad connection on the back of the dash? But I can't see this stopping the battery from charging?

Anyway, thanks in advance, hope you can either offer some suggestions or confirm my suspicions on the alternator :)

Rich

Title: Re: Possible faulty alternator?
Post by Tompion on Apr 30^th, 2011, 4:10pm

Sounds like more than one fault, possibly the alternator got damaged when everything went off but check the terminals are tight on the alternator & for continuity from the terminals.
Might be worth checking the instrument cluster connectors are clean and properly seated.

It’s worth testing all fuses with this sort of problem as they can be strangely linked on the Scorpio.

Relay 21 has been posted as “controlling all ignition on electrics, but the engine still runs”.

I assume it's a 12v?

Title: Re: Possible faulty alternator?
Post by Mike H on Apr 30^th, 2011, 4:27pm

If engine is running should be more like 14V, especially after a trip. Don't forget you can also use dash diagnostic mode to measure battery Volts, while it's running that is (?)

Title: Re: Possible faulty alternator?
Post by Highlander on Apr 30^th, 2011, 6:04pm

I'd check the bottom compartment of the passenger side fusebox for water, not the centre part where the fuses are but the base that clips on underneath.

Title: Re: Possible faulty alternator?
Post by RichKavanagh on Apr 30^th, 2011, 6:13pm

@Tompion - It's a 2.9 16v - I swapped Relay 21 with R18, no change. Connections confirmed as good on the alternator. Might take the dash apart if it's possible that a dodgy connection there could prevent charging?

@Mike H - Onboard diags reveal the same as the multimeter, no increase with the revs, running high 11v

@Highlander - Does this just unclip? Will have a look later

All other suggestions (very much) welcomed!

Title: Re: Possible faulty alternator?
Post by Tompion on Apr 30^th, 2011, 6:21pm

on 04/30/11 at 18:13:55, RichKavanagh wrote:

@Tompion - It's a 2.9 16v -

Is it a Scorpio?
2.9 24v
2.9 12v
2.0/2.3 16v

Title: Re: Possible faulty alternator?
Post by RichKavanagh on Apr 30^th, 2011, 8:49pm

Whoops, sorry, 2.9 12v Scorpio

Title: Re: Possible faulty alternator?
Post by Tompion on Apr 30^th, 2011, 8:50pm

If it's a 12v the rev-counter receives its signal from the alternator.

Title: Re: Possible faulty alternator?
Post by Mike H on May 1^st, 2011, 12:29pm

There's a clue! ;D

on 04/30/11 at 18:13:55, RichKavanagh wrote:

@Might take the dash apart if it's possible that a dodgy connection there could prevent charging?

Extremely unlikely has owt to do with it

Quote:

@Mike H - Onboard diags reveal the same as the multimeter, no increase with the revs, running high 11v

OK so my money's on kn@ckered alternator / brushes / rectifier whatever - it aint doing what it's supposed ta ;D

Title: Re: Possible faulty alternator?
Post by Tompion on May 1^st, 2011, 3:38pm

on 04/30/11 at 18:13:55, RichKavanagh wrote:

@Tompion - Might take the dash apart if it's possible that a dodgy connection there could prevent charging?

I didn’t spot you’d written that, I was meaning the rev-counter fault, but since yours is a 12v it does tend to indicate an alternator problem (the 24v & 16v’s don’t receive the rev signal via the alternator).

Title: Re: Possible faulty alternator?
Post by Cosray on May 1^st, 2011, 8:36pm

Hi all -- looks like two or
three diodes of the alternator pack gone.

Have an electrical specialist check her out -

HTH
Ray

Title: Re: Possible faulty alternator?
Post by RichKavanagh on May 1^st, 2011, 11:13pm

Thanks for all the replies, looking like an alternator issue then.

There's an alternator and battery firm on a nearby industrial estate, I'll charge the battery again and take it for a spin over there later in the week.

I'll let you know what happens!

Title: Re: Possible faulty alternator?
Post by Mike H on May 2^nd, 2011, 12:11pm

Yes do. Note diode packs have been known to go before (there's one other topic I can think of about it)

Title: Re: Possible faulty alternator?
Post by Cosray on May 2^nd, 2011, 3:31pm

Mike, mine did about two years ago - same indications while driving..!

Forgot about it until someone signalled my faintly glowing batterylight (hidden for me behind the spokes of the wheel but clearly visible in a dark garage). Had all sorts of vague starting probs.

MOT inspector noticed it too and I had the diodepack replaced I think for € 75 incl. labor. Crazy - it was only 15 years old ;-))

All's well now.

HTH
Ray

Title: Re: Possible faulty alternator?
Post by RichKavanagh on Jun 16^th, 2011, 6:45pm

Hi everyone.

Just to confirm, the alternator was indeed at fault.

And yes, it has taken me this long to get it all going again :-[

But so very happy that it's back on the road ;D

Title: Re: Possible faulty alternator?
Post by Mike H on Jul 11^th, 2011, 5:21pm

Congratulations http://livinginthepast-audioweb.co.uk/images/misc/th_thumbsup.gif