URGENT HELP - battery light
URGENT HELP - battery light
Author
Discussion

ropey

Original Poster:

372 posts

281 months

Saturday 3rd July 2004
quotequote all
Hi all,

Hope that there's enough of you who haven't gone to PF to help me out here.

Just went down to start the Chim (1998, 4.5), alarm off ok, doors opened ok, started fine, but the battery warning light is staying on.

Car sounds absolutely fine - perfectly normal. All belts turning in the engine.

If I press the throttle to about 4000 rpm the light goes out briefly and then comes back on as soon as the revs drop.

Last drove the car last Sunday - to Goodwood and back (from central London) - so battery should have had a good charge. Plus the battery was replaced 6-9 months ago.

Had a service recently with David Batty and he said all was fine.

Only other work done on the car was last weekend when I put the front of the car on ramps and reconnected the spade connector on the oil pressure sensor. This is also reading a little low today too. Did poke around the 100amp fuse next to the starter motor as maybe replacing that shortly - noticed the housing for the fuse was fairly knackered.

Any ideas chaps - got AA man on the way, but would be good if I could give him an idea of what might be the issue.

Girlfriends birthday this weekend - why does this have to do this now??!! FFS!!!!!!!!

Please help?????!!!

Cheers,
Ropey

Leadfoot

1,918 posts

310 months

Saturday 3rd July 2004
quotequote all
Sounds just like Marcos Maniacs predicament

www.pistonheads.com/gassing/topic.asp?t=109562&f=13&h=0

Psychobert

6,318 posts

285 months

Saturday 3rd July 2004
quotequote all
Might be the fuse, or the battery with a dead cell, or the laternator not charging. See if the output from the alternator is ok when running, thatmight help narrow down the problems..

ropey

Original Poster:

372 posts

281 months

Saturday 3rd July 2004
quotequote all
The very nice man has just been!! It was the fuse next to the starter motor - it had melted. So he's bypassed the fuse - and the alternator is now charging fine.

Won't drive it til next weekend, when I shall be taking it over to brother-in-laws for replacing 100amp fuse, and exciter wire from imob to the starter motor. Then all should be dandy!!

Thanks for the advise chaps - and thanks to TVR Centre Barnet - who also gave me advise over the phone.

Cheers,
(One very relieved) Ropey

Leadfoot

1,918 posts

310 months

Saturday 3rd July 2004
quotequote all
ropey said:
It was the fuse next to the starter motor - it had melted. )


it'd melted & you've got it bypassed! A hell of a short is needed to melt a 100A fuse, for f**ksakes don't use the car utill:
>You know why it melted & that's fixed
>you've put a new fuse in
The fuse link usually fails thru' vibration induced fatigue *not* melting for no reason.

Let us know what burning fibreglass smells like eh?

crankedup

25,764 posts

272 months

Saturday 3rd July 2004
quotequote all
Are you sure that the fuse has been bypassed This is an extraordinary thing for a mechanic to do and highly dodgy to say the least. Call the AA and query now if I were you.

GreenV8S

31,011 posts

313 months

Saturday 3rd July 2004
quotequote all
It's hard to see what the point of the fuse is since the only way you could blow it without setting the rest of the wiring loom on fire is to short the main power lead to earth. If that happened, isolating the alternator probably isn't going to save you since the battery would still be connected to the other end of the main power cable so you would presumably have a thousand amps or so going in from the other end - briefly? My guess is the fuse broke in half rather than blew, with just enough contact between the two halfs to keep you going until the heat buildup started melting things. It wouldn't take much current to do that - once you start passing current through a dry joint you can easily dissipate hundreds of watts of heat.

>> Edited by GreenV8S on Saturday 3rd July 21:55

ropey

Original Poster:

372 posts

281 months

Monday 5th July 2004
quotequote all
It may not have been melted as I actually didn't see it. I suspect he was exagerating - and meant blown instead. As mentioned in my previous post, the fuse and connector was fairly knackered anyway, as I spotted last week when it was up on ramps.

Just spoken to David Batty who said driving it as a one off will be fine - but obviously continuing to drive with the fuse by-passed is not a good idea, as the fuse is there for a reason.

As for why the AA did that - he knew I had one on order anyway, and he didn't have one to replace it (not unsurprisingly). I won't be using the car all week anyway, so will only have the hour journey over to my BIL when we will then replace the fuse.

Let you know how I get on.

Cheers,
Ropey

ropey

Original Poster:

372 posts

281 months

Tuesday 13th July 2004
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Just to finish off this thread - I drove the Chim over to my BIL this weekend, and all was fine - no melting plastic, no smoke, and no alternator light. Got her up on ramps, and all is now sorted. Phew - just in time for the trip to France.

Ropey

Leadfoot

1,918 posts

310 months

Tuesday 13th July 2004
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Good man. Carrying any spare fuses (+ 8mm socket to change them with)?

ropey

Original Poster:

372 posts

281 months

Tuesday 13th July 2004
quotequote all
Have a host of spare normal fuses, but no 100A fuse. I would need a French AA man to get underneath the car anyway. I'm not that thin!!

Ropey