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Discussion Starter · #1 ·
Hi All,

After sitting around under covers for about three years, my 1995 F has successfully negotiated an MOT. However, it has decided that it doesn't want to charge its battery any more.

The battery was initially my suspected faulty component, but that has now been replaced with a new unit and know/tested to be all good.

I have spent the morning on/under it and checked out a lot of different things. On this basis, I am now pretty confident that the alternators has packed up. A new one is reserved and has my name on it (payment on collection) and will be available for collection at our local ECP on Tuesday morning.

So, that gives me a little time to double check with all of you that I havent missed anything. Today I have done the following:

Cleaned both battery terminals and cables
Cleaned the battery negative to body earth connection
Checked the battery voltage (across the terminals), with the engine off = 12.64 V
Checked the cranking voltage = 10.5 V
Engine running (at battery) = 12.20 V
Checked the engine bay alternator/battery fuse (70A) - all good and with clean contacts
Tested the voltage between the alternator red/positive terminal and ground - engine off = 12.20 V
Tested the voltage between the alternator red/positive terminal and ground - engine running = 12.20 V
Removed all access points and the OSR road wheel and started the car - belt can be seen rotating along with the pulley on the alternator.
Disconnected the alternator wiring loom and thoroughly cleaned everything.
Removed the alternator itself and cleaned the mounting/bolt points
Refitted the alternator and wiring connections - started the engine - exactly the same reading as before...
Checked and cleaned the the wiring connections at the starter motor (as they share a positive connection point).
Started the car again and checked for charging voltage - nope, still only measuring just over 12 V at the battery.

So, the question is: is there anything that I have missed that might be the fault?

Thanks in advance.
 

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MG TF
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Does sound like the alternator, I would think one of the diodes has gone as the voltage is lower with the engine running.
 

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Discussion Starter · #4 ·
Thanks guys, much appreciated. The new one, with the ECP discount code is coming out at £65.99, so I don’t really see the point in try to repair it either.

I really just wanted to make sure that I hadn’t missed anything silly, before I condemned it and put my hand in my pocket.
 

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mg_tf
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I had an alternator go. All the lights on the dash started to come on (or something along those lines) whilst I was driving - obviously some sort of major electrical fault - but I managed to keep the car going for 20-30 minutes until I got home (just - it started to misbehave in the last mile). Considering the age of these cars, as you say, replacing the alternator is a good idea even if it is potentially repairable.
Interesting sidenote, I can't remember the make of my replacement alternator but it sounds very distinct, almost with a high-pitched turbo whine!
 

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Discussion Starter · #6 ·
I collected the new alternator this morning. Fingers crossed for a break in the rain after work to fit it and see if this solves the problem...
 

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Discussion Starter · #7 ·
Well the weather held up and its fitted. The good news is that I now have a very healthy 13.79 volts going back to the battery.

Happy days.
 
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