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 71 
 on: January 29, 2018, 01:21:21 pm 
Started by TELBOY - Last post by TELBOY
Hopefully winter has been and gone. Whilst replacing brake pipe clips I noted that the outside fuel tank strap had suffered from the dreaded metal worm! so I had to make one of these and fit. Relatively simple task but on first glance the rotted one looked ok but the tank had dropped and was resting on the chassis.

 72 
 on: January 26, 2018, 03:38:44 pm 
Started by sc1962 - Last post by sc1962
thanks for that pete.im getting no feed at the screen at all,so I'm on it this weekend Cheesy

 73 
 on: January 26, 2018, 01:16:08 pm 
Started by sc1962 - Last post by suffolkpete
It is a 4 pin (pins 1,2,3 & 5 used)  The supply is fused at 16 amps, so the rating should be at least that.  Pin 1 is ground, pin 2 is the supply from the switch live when switched on and ignition on, pin 3 is a permanent live supply, fused at 16 amps from the fuse board in the LH front wing and pin 5 is the feed to the HRW, this and the HRW ground are fed to the screen via the two struts, which should be insulated from the body (note, some replacements aren't).  My advice would be to start from the screen and work back before suspecting the relay.

 74 
 on: January 25, 2018, 03:13:23 pm 
Started by sc1962 - Last post by sc1962
hi everyone,does anyone know what the hrw relay should be  in a 1.6 murena ?? is it 4 or 5 pin,open or closed and what ampage it should be ?? I'm going to swap it out hopefully as a start point in an attempt to get the hrw working as it should as I'm struggling to see out the back window lol

thanks as always

steve

 75 
 on: January 24, 2018, 01:09:45 pm 
Started by THERACEFACE - Last post by mhi
The resistor itself is on the expensive side (in the region of 50EUR, as I recall), but thats still nowhere near the amount of hours you'd pay for, if you delivered the car to a dealer to have this fixed .-)

Thank you very much for this (old post) advice. My aged J63 developed the same problem, with the same cause.

Lennart is right that the fan motor and resistor are horrible to get at, and that the wiper mechanism has to be removed before the heater box. On mine, right-hand-drive, one of the heater box fixings is incredibly difficult to get at. I had to buy a 10 mm flexible-end ratchet spanner, and extend it with another spanner, to reach past the heater box, heater and air-con pipes, and brake master cylinder, and even then it must thave taken 15 minutes to remove that single nut.

The good news is that a new resistor pack is not needed. There's a little thermal fuse, cost 99p online (about 1.20) including postage, along the side of the resistor. Cut out the old fuse and connect a new one, with a crimp or screw connector rather than solder, and save the cost and waste of a complete resistor. The critical information needed is the cut-out temperature, which is 240 C for mine. Look for "thermal fuse 240C" and buy one before starting work. Check the temperature marking on the old fuse when you do get it out, though: this is a safety-critical part, to avoid a fire if the heater air-flow stops.

The reason my resistor overheated is that the fan motor bearings needed lubrication, so the fans were not running fast enough. I've given the bearings a few drops of oil (transmission oil, but I don't think that's critical). Ideally I would have replaced the fan motor's carbon brushes as well, but they look to have another 100 000 km before wearing out.

Before fixing the heater airbox back in the car, rest it on top of the engine and connect up all 3 cables, turn on the ignition and test the fan at all speeds. That can save a lot of work if something's not running smoothly and quietly.

I would like to replace the sound-insulating soft cover of my heater air-box, because after 24 years it's getting ragged. Is it possible to get the right sort of engine-compartment-grade fabric and make up a new cover?

 76 
 on: January 10, 2018, 01:49:59 pm 
Started by Matra_Hans - Last post by Matra_Hans
Nice to hear that our old treads can be useful.

Hans

 77 
 on: January 06, 2018, 12:19:45 am 
Started by Matra_Hans - Last post by BeaterBlogDave
Just a quick thanks for this thread.  My fog lights were not working and after checking the bulbs and fuse I found this post.  After re-soldering the broken white wire I have working fog lights!

 78 
 on: January 05, 2018, 10:52:58 am 
Started by roy4matra - Last post by roy4matra
Hello all,

... This was the last one from their stock, but they tell me they can get some more cast if there is sufficient demand.  They would require at least five and the run would be done early 2018 if I could give them the orders and deposits.  If we get orders for 5, then the cost would be 295 Euros each plus carriage cost (approx. 18 Euro - that was the cost for mine).  If the numbers could be as high as 10 then the price would be reduced accordingly.

So the question is: do any of you 2.2 Murena owners wish to have one of these ribbed alloy covers for your engine?

Please let me know, preferably by my domain name email as I don't get on the forum regularly, but you can message me here if you wish.

Roy

Happy New Year to all you Matra fans.

I posted this a couple of months ago and I've had a few comments/requests so far, and the number who would be prepared to pay for one of these alloy cam covers is three.  Just two more and I could give them an order for five and they would go ahead.  Please note, the new ones will have a crankcase vent included for the 295 Euro price.

So, are there a couple of others out there that would like to improve the looks of their Murena 2.2 engines?

Roy

 79 
 on: January 03, 2018, 01:33:34 am 
Started by hrmarmg - Last post by hrmarmg
I've got a non-runner Grand Espace RXE V6 Auto (V reg, 2000) for parts. and will be scrapping it soon.  It's in Canterbury, Kent, UK.  If anyone needs bits then you are welcome to take what you want  (or if easy enough to get at, I can get things off and post).  Roger

 80 
 on: December 11, 2017, 01:21:28 pm 
Started by njesper - Last post by roy4matra
...  No need to worry about the reverse voltage, the lamp goes out when the voltages either side are equal, so there is negligible reverse bias.

This not quite right I'm afraid, and could lead to a serious problem.

The ignition warning bulb has to allow current to flow BOTH ways and an LED will only work with current flowing in one direction.  Why does it need to allow and illuminate with flow in both directions?  This is because sometimes the alternator fails and OVER charges.  I have seen this a number of times during my working life and even experienced it myself not long ago.


I have to disagree, the alternator voltage always has to be higher than that of the battery in order to charge it.  If what you say is correct then the lamp would always be lit.  In a machine-sensing alternator, the regulator and field winding is fed from the ignition warning light via a diode which is forward biased when the alternator is not charging and allows the lamp to light and is reverse biased when the alternator output exceeds that of the battery, extinguishing the lamp.  I think that in the scenario you describe, the diode had failed short-circuit, lighting the lamp and causing the regulator to malfunction, or possibly the overcharging had blown the diode, but had the diode not failed the overcharging would have continued anyway without lighting the lamp.


Sorry but I know I'm right here Peter.  The ignition warning light is basically a form of 'balance meter'.  When the voltage is higher one side than the other then current flows from the higher potential to the lower potential and the bulb glows.  The bigger the potential the brighter the bulb glows.  But it must be able to flow both ways.

The bulb gets its feed on one side from the ignition switch, which in turn gets its feed from the battery.  So one side has battery voltage.  The other side of the bulb connects to the alternator and when the engine is not running this side is connected to earth so the bulb glows bright.  When the engine is started the earth is effectively cut, and the regulator connects the alternator voltage to that side of the bulb, AND it is charging the battery so the battery side of the bulb also has virtually the same voltage.  The difference is so tiny that a bulb will not light up.*  So with the same potential both sides of the bulb, it goes out.  (Probably if you had an accurate enough meter connected you would see the tiny difference)

If the alternator stops charging or its charge rate drops below the correct figure, the potential is now higher on the ignition side as the battery at this stage is still 12v nominal (actually probably 12.8 to 13.0 volts for a battery that has just been charging) as the battery has such reserves that its voltage is slow to drop.  The alternator side will have dropped immediately so the bulb starts to glow.

Now if the alternator starts overcharging, the alternator side increases immediately above 14.4v which is the normal maximum but the battery will still be at roughly 13.2 volts (a 12 volt battery has 6 cells with 2.2 volts each max.) and it won't change because its mass and reserves do not change quickly, so the potential difference is now the opposite way and the current flows 'backwards' and the bulb again starts to glow.  I've seen alternators that have started over charging go over 18 volts but a battery will simply get so hot it will boil the fluid away and buckle the plates before its voltage has increased to match the overcharge voltage.

In the sixties and seventies the Lucas ACR alternators had Zener diodes fitted that simply blew if the voltage spiked such as when jump starting but also if the voltage climbed rapidly for any reason.  This protected the rest of the alternator.  We often used to fix the problem and simply replace the Zener diode and the alternator was fine again.  Saved us a lot of work on those vehicles where it was a swine to replace the whole unit, but getting at the back was easy! Smiley

Roy
*P.S. this is another reason for using an incandescent bulb - it takes a certain amount of potential difference and current flow before there is enough to make the element glow.

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