rich
23 posts
Joined: 17/01/2005 13:51:37
Location: Henfield United Kingdom (Excluding channel Islands)
Short Circuit?
hi all, I have an 89 flame red with a 4 fuse box. Im having trouble with the top 35 amp fuse (indicators and rear window demister circuit). The fuse blowswhen the engine is running, but is okay when i have tested it with the ignition at position II. No particular switch overloads the circuit and I suspect that engine vibration and an exposed wire/bad contact might be the culprit. I have done as much as I can and need to send the little brute to a local garage - does anyone have any suggestions before they start to interfere with her? Also, can anyone recommend a good rolling road tune in the Brighton area? Thanks, Rich
Posted: May 17, 2005 02:06 PM
Richard
15 posts
Joined: 29/10/2004 15:31:39
Location: Grantham United Kingdom (Excluding channel Islands)
Short circuit
Hi you may have had the problem fixed by now but just incase I had the same problem it took me ages to sort it out all it was on mine was dirty earth connections on the rear demister.
Posted: Jun 06, 2005 07:36 PM
Stuart
4 posts
Joined: 24/04/2005 21:02:47
Location: Ingå Finland
Help needed: How to check for an open circuit?
Hi, After reading some previous posts about alternators not charging batteries I was convinced that this is whats happening to my Mini. I read about the posibility of open circuits in the Haynes manual, but was praying that that wouldnt be the case. However, I took the battery off charge yesterday afternoon (and connected it to the car). Twenty-four hours later its dropped from 13.56V to 12.88V. I must admit, I havent tried the same test with it not being attached to the car as the batterys only two years old. So, can anyone how I can start checking for an open circuit? I I put a multimeter over the battery and then remove each of the four fuses in turn and see if theres a drop in drain on the battery? Any advice would be appreciated! Stuart
Posted: Apr 11, 2006 03:03 PM
Help needed: How to check for an short circuit?
...and that would be a short circuit. Not an open circuit...
Posted: Apr 11, 2006 05:09 PM
jonathan
28 posts
Joined: 19/09/2005 20:07:38
Location: rochester United Kingdom (Excluding channel Islands)
have you tried using the multimetre on the altornator to see if its actually charging you will need the engin running
Posted: Apr 17, 2006 01:08 PM
Chris
332 posts
Joined: 04/05/2006 21:28:31
Location: Mid Calder United Kingdom (Excluding channel Islands)
First thing to try is to repeat the charge cycle you have already done but then don't attach the battery to anything , just leave it disconnected and then measure the voltage, because I think you'll find that your measurements aren't too far from normal. A battery floating at about 12.8V doesn't necessarily mean a problem, on a battery a couple of years old this can be a normal situation.
Posted: May 04, 2006 09:50 PM
Minimad
47 posts
Joined: 28/02/2005 17:58:43
Location: Bristol United Kingdom (Excluding channel Islands)
Dramatic RPM drop when electrical circuits switched on
Hi
I have recently built a 1380 fast road engine. At standard idle things are fine but as soon as I switch the lights or any other electrical circuit the RPM drops by 200. Is this due to the state of tune or maybe a faulty alternator/battery
Thanks in advance!
Posted: Sep 12, 2006 04:14 PM
Tim
1849 posts
Joined: 18/10/2004 09:40:59
Location: Bournemouth United Kingdom (Excluding channel Islands)
Is that the RPM as measured by the tachometer or by your ears? In other words, is it a real drop in rpm or just an indicated one?
Posted: Sep 12, 2006 04:20 PM
By Tacho
Posted: Sep 12, 2006 04:24 PM
Bandit57
3 posts
Joined: 05/08/2006 00:58:35
Extra load on electrical circuits puts a load on the alternator which may result in a drop in revs especially at idle - I'm not surprised this happens. Physics law of conservation of energy - you don't get 'owt for nowt!! Generation of electrical power takes energy ... where does this come from?.... your engine, hence the drop in revs.
John
Posted: Sep 13, 2006 12:04 AM
Yes I do know some basic physics.
However do you not agree that 200 RPM drop is excessive with just the side lights on!
When I had a 998 lump you could run everything with no more than 80 RPM drop!
Nathon
Posted: Sep 13, 2006 04:12 PM
pickme
672 posts
Joined: 08/09/2004 23:10:14
Location: Chippenham United Kingdom (Excluding channel Islands)
Don't take the standard rev counter too seriously. They are not very accurate.
Posted: Sep 13, 2006 08:01 PM
Okay whatever happened to the people with knowledge on this forum.
The information is in black and white the engine speed drops by 200 RPM (In Fact 208 +/- 2 RPM). My car hasn't got a tacho fitted yet, this measurement was taken using a digital engine analyser.
All I am asking is does anyone know the reason for this. Is it likely to be the state of tune of the engine or a faulty battery or alternator?
Thanks
Posted: Sep 13, 2006 10:32 PM
Thinking logically, if it's excessive load on the alternator causing this then temporarily diconnecting it (or removing the fan belt) will allow you to prove or disprove the theory. If that makes no difference, then it must be a voltage drop across the coil. Either way, it suggests a wiring fault.
Posted: Sep 14, 2006 07:40 AM
Thank you!
Posted: Sep 14, 2006 09:23 AM
131 posts
Joined: 18/02/2005 08:56:10
Location: Leamington Spa United Kingdom (Excluding channel Islands)
Good afternoon,
I have a similar problem, which I managed to diagnose as a bad engine earth. Added and extra earth, which resolved the issue.
Could be as simple as this.
Posted: Sep 19, 2006 12:07 PM
Roy
261 posts
Joined: 19/09/2005 19:34:20
Location: huntingdon United Kingdom (Excluding channel Islands)
Hi.... My engine revs also drop by about150-200 revs when lights are switched on but only when dipped or full beams are used.
I just live with it as my lights are nice and bright and none of the other electrical systems seem to be suffering as a result...
Posted: Sep 20, 2006 09:51 PM
dougc
2 posts
Joined: 23/03/2006 11:48:23
Location: Saffron Walden United Kingdom (Excluding channel Islands)
Printed circuit board on the back of the instrument panel
I have a 1989 mini thirty with the standard gauges, and recently the speedo light died. So i got a new bulb (could only get 3w in my local shop, does that make too much of a difference compared to 2.2w?), fitted it and worked for a few minutes. I took the bulb and holder out and had a look round the back and the contact area on the printed circuit board is corroded and so a connection cannot be made. Any tips, anyone with a spare pcb? contact me on the forum or douglascrumpler@hotmail.com with any offers.
Cheers
Posted: Dec 16, 2006 02:39 PM
mini_dave
11 posts
Joined: 13/10/2006 14:50:52
Location: wokingham United Kingdom (Excluding channel Islands)
solder a new contact point on using a soldering iron
Posted: Dec 17, 2006 10:16 AM
Ditto the soldering iron... worked for me when the PCB got torn (oops).... and sorted out the weirdly behaving rev counter and temp guage....
Posted: Dec 17, 2006 11:06 AM