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Author Topic: Charging light on Murena 2,2  (Read 1978 times)
variator
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-83 Matra Murena 2.2


« on: September 07, 2014, 09:55:05 pm »

I have a problem with charging on my 2.2 Murena now. After a leak of coolant into the regulator on the alternator then charging light comes on, but after I plugged leakage and dried and cleaned regulator / brushes, extinguished the lamp.
The other day it brightened it up again, but dims if I turn on consumers in the car, for example. heater fan. This error may well just be the result of two things ...... either regulator is faulty or there is one or more diodes in the rectifier broken?
The car has long before the light began to brighten, charged bady .... actually below 14V, so I have suspected a bad diode.

Have any of you guys experienced anything similar error with charging?

I have ordered a new regulator so I can try this first.


 I was by the way on a motor show with over 350 cars today, I was the only one with Murena:-)

« Last Edit: September 07, 2014, 10:12:35 pm by variator » Logged

2001 Saab 9-5 2,3T, 1981 Porsche 928, 1981 Honda cb 900 F, 1968 Triumph Trophy TR6R, 1986 Yamaha RD 350 YPVS
roy4matra
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« Reply #1 on: September 08, 2014, 01:08:25 am »

I have a problem with charging on my 2.2 Murena now. After a leak of coolant into the regulator on the alternator then charging light comes on, but after I plugged leakage and dried and cleaned regulator / brushes, extinguished the lamp.
The other day it brightened it up again, but dims if I turn on consumers in the car, for example. heater fan. This error may well just be the result of two things ...... either regulator is faulty or there is one or more diodes in the rectifier broken?
The car has long before the light began to brighten, charged bady .... actually below 14V, so I have suspected a bad diode.

Have any of you guys experienced anything similar error with charging?

If you think about the symptom it is the reverse of a normal under-charging system.

Normally the light starts to come on when it is under-charging and if you then switch something on, say putting a load on such as the heater fan, the extra load would make the ignition light come on more.  Here, what you are saying is the light is on bright and then switching the heated fan on makes it dimmer.  That indicates it was over-charging, and when you put the load on, it took some of the charge so the light dimmed.  An ignition warning light is simply a 'balance meter'.  The voltage both sides of the bulb (battery one side, alternator the other) should be equal and it stays off.  If either are greater or less current flows and the bulbs starts to glow.

Quote
I have ordered a new regulator so I can try this first.


That may well be the fault, since the regulator sets the charging rate and if it is over-charging (or under-charging) the regulator is suspect.  Obviously it can be other things like poor connections, but see how it goes after you fit the new regulator.

Roy
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variator
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Posts: 95


-83 Matra Murena 2.2


« Reply #2 on: September 08, 2014, 04:58:24 pm »

It is definitely not a case of overcharging! Charging has been bad since I took over the car, it is located right on the border all the time.
A 12v battery must have what I understand, at least 13.8 V to charge up, here are charging been around this voltage.
I do as you suggest and replace the regulator and see how it goes. Otherwise, I'm afraid this may indicate faulty diodes.

Regards
Terje
« Last Edit: September 08, 2014, 05:27:00 pm by variator » Logged

2001 Saab 9-5 2,3T, 1981 Porsche 928, 1981 Honda cb 900 F, 1968 Triumph Trophy TR6R, 1986 Yamaha RD 350 YPVS
Oetker
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« Reply #3 on: September 08, 2014, 07:11:00 pm »

It is definitely not a case of overcharging! Charging has been bad since I took over the car, it is located right on the border all the time.
A 12v battery must have what I understand, at least 13.8 V to charge up, here are charging been around this voltage.
I do as you suggest and replace the regulator and see how it goes. Otherwise, I'm afraid this may indicate faulty diodes.

Regards
Terje

You meen needle of the gauge is right at the border?
It seldom is.
Most of the time it's more to the left.


Did you measure the voltage at the battery?

Because  the point to let the air out the cooling systtem is above the altenator water comes in there easy.

In my case that leaded to defective diodes, but then you have no charge at all.


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I feel like Jonah, only my fish looks different.
Murena 2.2 Red 1982. Murena 1.6 black on places.
variator
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-83 Matra Murena 2.2


« Reply #4 on: September 10, 2014, 10:06:57 pm »

I have measured the charging voltage and it has been 13,6-13,8V ....... that's what I mean by "on the border"
The charging voltage must, what I have learned, be at least 13.8V for the battery to charge.
The fact that the charging voltage has been so low may well indicate that one diode is defective, it will lose approximately 30% of the charging voltage if so.

Now  the charging voltage have dropped to 13,3V at 3000 r / min and the charging light has started to light. This would then perhaps indicate that two diodes are defective?


Does anyone know where it is possible to buy the diode bridges for the Paris Rhone A13N10 alternator?
« Last Edit: September 10, 2014, 10:44:39 pm by variator » Logged

2001 Saab 9-5 2,3T, 1981 Porsche 928, 1981 Honda cb 900 F, 1968 Triumph Trophy TR6R, 1986 Yamaha RD 350 YPVS
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« Reply #5 on: September 11, 2014, 07:35:21 am »

Best is to take  the alternator to a firm that can test it.
The parts are more or less universal.
You can also go this way.

http://www.matrasport.dk/forum/index.php/topic,1080.msg8241.html#msg8241


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I feel like Jonah, only my fish looks different.
Murena 2.2 Red 1982. Murena 1.6 black on places.
roy4matra
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« Reply #6 on: September 12, 2014, 03:56:26 pm »

I have measured the charging voltage and it has been 13,6-13,8V ....... that's what I mean by "on the border"
The charging voltage must, what I have learned, be at least 13.8V for the battery to charge.

This is not true.  A modern battery is a 6 cell lead acid battery and since all cells are 2.2 volt nominal that adds up to 13.2 volts nominal maximum.  Charging systems should charge anywhere between 13.4 and 14.4 volts.  It will vary depending on load and engine/alternator revs.  So your 13.6-13.8 volts is perfectly fine.  You can see the reason why it must be 13.4 volts minimum charge so that it is at least 0.2 volts above the battery possible maximum and will have a positive charge.

Now there are some new batteries that have a silver-calcium content and specifically are used on many Fords and require upto 14.8 volt charge, so the newer Fords are tweaked to charge at that higher voltage.  If you fit a calcium battery to a car not designed for them, then you could have a problem with the battery not getting enough charge.

Quote
The fact that the charging voltage has been so low may well indicate that one diode is defective, it will lose approximately 30% of the charging voltage if so.

Now  the charging voltage have dropped to 13,3V at 3000 r / min and the charging light has started to light. This would then perhaps indicate that two diodes are defective?

Not sure why you think it has to be one or two diodes, but faulty regulators are more common than diodes, especially with these Paris-Rhone/Valeo alternators.  A faulty diode usually either stops it charging altogether or allows it to drain as it allows a reverse current flow.  In my experience these alternators are highly unreliable (compared to good ones like Bosch and Hella).  Since any Murena is old, and you have a new regulator, have you check all the other contacts?  I have found the wiring and contacts inside the rear of the alternator either badly corroded or even broken.  This is where I would start.  Don't forget the earth side too.  Check alternator to engine and engine to chassis earth.

When you are checking the charging, always test the voltage at the battery terminals.  If you take readings anywhere else be prepared for a drop as the circuits are notorious for loss of voltage owing to poor connections.  Modern normal lead-acid batteries cannot stand voltages over 14.4 volts so you couldn't use one on a Ford designed for upto 14.8 volt charge.  Modern batteries only have lead 'sponge' plates unlike the older batteries which used to have proper lead plates and had a higher internal resistance.  This was the reason old cars with dynamos used to charge around 15-16 volts and if you fit a modern battery to an old 50's or pre-war car you have to adjust the regulator down otherwise it overheats the battery.

Quote
Does anyone know where it is possible to buy the diode bridges for the Paris Rhone A13N10 alternator?

It is now classed as a Valeo so try searching under that name too, but I always found spares for these a problem since they were not common in the UK in the past.  However a quick check shows lots of Valeo diode packs for sale at about £28.

Roy
« Last Edit: September 13, 2014, 11:47:11 pm by roy4matra » Logged

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