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        General >> Problems >> Sudden Powercut at 160 km/h - 100 Mph
        
(Message started by: Cosray - The Hague - Holland on Aug 23^rd, 2005, 9:58pm)

Title: Sudden Powercut at 160 km/h - 100 Mph
Post by Cosray - The Hague - Holland on Aug 23^rd, 2005, 9:58pm

Symptoms

'95 24v Cosworth in good condition but for possible high Fuel Rail Pressure (see post)

Daylight, headlights on due to dark clouds, no rain, doing 120 km/h on the motorway, I accelerated for overtaking.
24v engine performed immediately, autobox nicely changed into 3d gear, doing 160 km/h in seconds.
With no warning engine died, cassette player died, instrument panel needles went dead, then wild, needles spinning, then back to correct readings, all car closure monitor lights on/off --
and in 3-4 seconds everything was back to normal...

Slowed down stupefied to look, smell & inspect: everything 100% normal.
No excessive or abnormal indications; car's been running perfectly ever since.
Radiostations on the radio/cassetteplayer were NOT lost.

Observation

I cannot think of a valid common cause for this behaviour.
Battery failure/short? Generator failure? (No, since there is battery back up.)
EEC-V breakdown?
But - why then did the radio/cassetteplayer momentarily die without losing its radiostations?
Timer/battery saver circuitry faulty?

Question
Anyone having had similar experience?
Any clues to this unusual (and distracting) behaviour?
Will/Can it happen again?

Looking forward,
Ray

Title: Re: Sudden Powercut at 160 km/h - 100 Mph
Post by Octavian_P on Aug 25^th, 2005, 5:20pm

If all the gauges fellt down, radio, did the lights go out as well ?, if so i think your battery connections are a bit lose.

Title: Re: Sudden Powercut at 160 km/h - 100 Mph
Post by dart on Aug 28^th, 2005, 10:29pm

Or dirty!
Think Oct got it right ;)
Check battery lead connections and all earth lead connections for dirt grime and tightness.
Undo ,clean,waterproof,refit.
Hopefully, Should do the trick! :D

Let us know
Neil

Title: Re: Sudden Powercut at 160 km/h - 100 Mph
Post by Cosray - The Hague - Holland on Aug 29^th, 2005, 1:15pm

Thank you Neil, Oct.

Did all your advised stuff; connections are rocksolid, in vaseline. Battery while driving, using instrument cluster measuring, reading varies between 12.9 V (full load, all 4 windowmotors on, all seat heaters, front- and rear window heater on) to 13.8-14.1 V (normal load).

Moreover, if the battery would have had bad connections while driving then the generator would have powered the system anyway, not causing the cut. This is the strange thing!

If the battery AND the generator would have momentarily died while driving THEN the radiostations would have been lost - but they weren't.
(The radio has a +12v memory lead which must maintain power to save stationsettings.)

That was the first incident.

Since then one more time the needles spun round when I switched my engine OFF after parking; a third time the needles spun round when I turned the ignition key to ON.

Everything repeat everything has been working flawlessly before, through amd following all 3 incidents.

As I understand it spinning instrument needles are a sign of the EEC-V power-on following reset.

Any other clues to this?
Looking forward, Ray

Title: Re: Sudden Powercut at 160 km/h - 100 Mph
Post by mr._floppy on Aug 29^th, 2005, 2:12pm

How's the fuse box, nice and dry ?

The speedo/tacho needle flip is usually manifests itself after a power break / resumption of power situation i.e. battery disconnection, fuse replacement, Etc.

Anyway, should you be doing excess of 100mph ?

Tut , Tut!

Title: Re: Sudden Powercut at 160 km/h - 100 Mph
Post by dart on Aug 29^th, 2005, 8:54pm

Well put Floppy ;D
And if fuse box and battery cover are intact and warmy cosy then it gets expensive!
electrical expensive!
The brain :-[
eeeck!
(And,Yes, a hundred :o you suprise me duck!)

Title: Re: Sudden Powercut at 160 km/h - 100 Mph
Post by Cosray - The Hague - Holland on Sep 5^th, 2005, 10:35am

on 08/29/05 at 14:12:30, mr._floppy wrote:

How else would one get from Hamburg to Munich in a day but using a plane? ;-)

Fuseboxes are dry; spotless; checked all fuses, cleaned relay connectors with contact spray etc.

I discovered the following predicatable behaviour, which could be a clue.

Key On, Engine Off.
Front and Rear window heaters on, all window switches pressed to make the windows jam, seat heaters on.
Using the diagnostic mode on the instrument panel I see the instrument panel voltage drop below 11 Volts.

Once I turn the ingition key again to On the instrument needles spin round.

So, it is/was definately a case of momentarily voltage drop, the reason of which I cannot fathom yet, since when driving or standing my battery voltage is never under 12.5 Volts.

If the generator would cut out momentarily then the battery would buffer that voltage loss.

I will pull all the fuses again and clean them to start with.

Curious, Ray

Title: Re: Sudden Powercut at 160 km/h - 100 Mph
Post by Eric_R on Sep 5^th, 2005, 12:37pm

Ray,
Yes, I think the clue to this is the system voltage. Once the voltage drops too low the electronic modules reset, and this can effect the main relays, turning them off. This happened to me briefly when I had a failing alternator - the whole car was dead for a few seconds, then came on again. Fortunately I was parked at the time.

It sounds as if the battery or the alternator are starting to fail. Have the battery discharge-tested and replaced if it fails the test. If you put all the electrical loads on and the voltage drops below 12v then the alternator is not charging properly - you probably need that replaced.
Flicking needles is a very common symptom of charging problems. ;)

Title: Re: Sudden Powercut at 160 km/h - 100 Mph
Post by Sian_RK on Sep 6^th, 2005, 11:44am

on 08/23/05 at 21:58:03, Cosray - The Hague - Holland wrote:

Check the ignition relay in the Auxilliary? (the long one, next to the battery) fusebox. I had this problem, replaced the alternator and battery, and it could well have been this relay all along. It's a black one, but I forget what location.

With mine, it would fail, giving precisely the symptoms you describe, and then when the car was switched off (the engine would still be running at this stage) it wouldn't restart for some time, eventually, it wouldn't restart at all.

Richard

Title: Re: Sudden Powercut at 160 km/h - 100 Mph
Post by Cosray - The Hague - Holland on Sep 6^th, 2005, 7:53pm

Thanks, great tip!

This weekend I will pull all relays and fuses and give them a rub with the old contact cleaner and a fiberglass contact scrubber.

There's probably some 10 year old grime hidden somewhere.

Will keep you posted!

Ray

Title: Re: Sudden Powercut at 160 km/h - 100 Mph
Post by Cosray - The Hague - Holland on Sep 13^th, 2005, 3:35pm

Hi all,

recently the 'spinning needles' come up often after a restart say, after a night's parking or even during the day.

I found by deliberate testing that, whenever I apply a large enough electrical load AND the instrument cluster's voltage drops below 12 V (be it with running or standing engine) THEN it will reset its instruments and spin the needles on a subsequent Ignition ON.

One of these 'large enough' loads appears to be... the remote closing and subsequent opening of the car's electric doorslocks + petroldoor!

With this casual event a large load is applied twice to the weak battery!

It still does not however explain the weird first experience when driving at 160 km/h though; see top of posting, since with engine running the car's voltage is between 13-14 V.

Anyway, I will replace my battery now, in time for winter!

Ray