Roy's Matra Enthusiasts pages
FAQ's: Frequently Asked Questions
- My Bagheera/Murena headlamps are very slow to come up or won't lift at all; or Both my dip and main beam come on together. What is wrong?
The Bagheera and Murena headlamp lift/lower mechanisms are vacuum operated and are very similar, but the Bagheera used a rear chassis cross-tube as a vacuum reservoir whilst the Murena has a proper reservoir tank (in ABS plastic). In all other respects they are virtually the same. There is a bar linking the two headlamps so both must go up or down together and you will not get 'one up, one down' like you used to see with Lotus Elans! There is an emergency manual cable to pull the lamp pods up in case of system failure, but this will only work if the vacuum is not trying to pull them down! If this is the case, then you must disconnect the vacuum pipe from the operating valve and block it off. The cable is near the left of the steering column under the dash, although not all Bagheera have this emergency cable. Also note that Murena have a headlamp raised/bonnet release interlock. This (if it is working!) is to stop you opening the bonnet whilst the headlamps are up as the bonnet would foul the headlamp pod inner edges as you lifted it, causing paint and body damage. If your interlock is not working please be aware of this point. One final point on the linkage: when the pods are fully up, it should go over-centre such that they lock in the up position. If you had to manually raise them, this locked position would keep them up whilst driving. Without it they would drop again, so make sure the linkage is correctly adjusted. To lower them manually you need to go under the front and push the bar back from the locked position.
Since the vacuum is taken from the inlet manifold, if there is an air leak anywhere in the system the engine will also run poorly owing to the leak causing a weak mixture. This can happen particularly on Bagheera owing to corrosion around the end caps of the cross-tube reservoir, but it can also leak at the operating valve, the servo, or any of the rubber joints, especially if these are still original! (look for splits or cracks in the rubber). To check if the system is air tight, try switching the lights on a day or two after the engine was last run. If there is no vacuum left in the system to lift the lights, there is a leak. If the headlights only lift when the engine is running, you definitely have a leak! If the light pods seem very loose or bounce slightly (from closed) when the car goes over bumps I would suspect you have a broken ball socket somewhere in the linkage. Check the short links to each headlamp and the sockets on the servo and rod. The sockets are plastic and may have cracked. The lift/lower double acting servo is mounted under the front left on the chassis near the front wheel. The operating valve is mounted in the front compartment under the bonnet, in the centre rear on a Bagheera, and on the left on a Murena (which can be under a cover) and is a white plastic valve with operating solenoid on one end. This often leaks but may only need stripping, cleaning, and reassembling. However, never oil the operating pin as this will only cause dirt to stick to it and make it worse. It should be clean, dry and free to move in the solenoid/valve.
If you have both dip and main beams coming on together, you probably have a diode shorted out. The headlamp pods have to be up for both beams, so the lift/lower solenoid needs to be operated for both switch positions, yet they must be electrically separated to prevent any backfeed from one circuit to the other. The circuit board diodes provide the answer. If both beams are operating together, the most obvious cause is a failed diode so check these first.
- The car/engine seems to struggle to reach the higher speeds/revs. What is wrong?
Following on from the previous answer, if there is a leak in the vacuum system and therefore the engine inlet, you will get a weak mixture, causing poor running and limited top end. So you need to check not only for leaks in the inlet manifold gaskets etc. but also the vacuum storage and headlight operating system. However, another possible cause is that many engines will have been uprated by replacing the original cast iron exhaust manifold with a stainless steel, full flow, four branch manifold with stainless silencer. This will allow better engine breathing but consequently require carburettor enrichment especially with the original Prep 142 or 'S' models. It has been found that if nothing else has been changed, then it may be just about O.K. but it will be marginal and if there have been any other modifications like a better camshaft then you should fit larger main jets to the side draught Solex carbs. The best way, as always, is to have it set up correctly on a rolling road.
- I have a number of electrical problems. What can I do?
First, do you have an accurate diagram for your Murena? If not, or you are not sure if it is accurate (even the factory ones were not!) then please contact me.
Electrical problems with old cars can generally be common and with the Murena it can be partly due to the corrosion that takes place in the open multi-pin loom connectors. The Murena and Espace also have circuit boards with the fuses and relays fitted, and these are often poor. For the Murena there was a replacement copy of better quality but at the moment these are all sold out and we don't know if more will be made. They are also not cheap - approx. 100 Euro each. The edge connector plug terminals can fracture across the bend reducing the contact with the board. These used to be used on some of the Austin Rover vehicles and the part numbers were ADU 7972 (small wire) or 7973 (larger wire). I believe they were also used on some Fords. However, these are generally no longer available and hard to get. I have come up with a better solution, so if you are interested, email me.
The Murena and Espace both have fully galvanised chassis, which can cause additional problems. This is due to the zinc creeping back in under the earthing points. It's a good feature that 'self-heals' small chips and scratches but is not what you need for a clean earth! Periodically remove all earths, and clean them back to bare metal, refit, secure, and cover with silicon. As for the multi-pin connectors, make sure they are good and haven't corroded (they will go green) and if necessary, repair them, and again seal with silicon grease.
- My Murena oil level warning light flashes all the time even though the level is correct. Why is this?
The system works as follows: Either the dipstick contains a sensor (1.6 engines) or a sensor is fitted into the sump (2.2 engines) and these send a signal to the control unit which is under the left hand side of the dashboard. When you turn the ignition on, you should pause to let it read and you should see the oil warning light flash once or twice. If the level is correct, it should then stop. If it doesn't flash at all, one of the terminals to the control may be broken as these use the same edge connectors as the circuit board plugs (see answer above). If it doesn't stop flashing, either the level is too low, a wire is broken, or possibly the sensor is broken. To test the sensor when cold and not in any fluid the resistance should be around 8.2 ohms. If you start up without that pause, it may interrupt the system during the read phase and sometimes it will continue to flash even though the level is correct. If the warning light starts flashing during running, it should be indicating the level has dropped below minimum level; so stop and check it. It might be another fault that has developed, such as a wire that broke once during a journey in my own car. When fixed, the system was fine again.
- My wipers have slow and fast speeds plus a 'flick wipe' operation but no intermittent setting. I have noted other Murena have an intermittent operation. Why doesn't mine?
All Murena have these features and so does yours. You probably haven't realised how it is switched on. The wiper stalk operates slow and fast speeds in the two positions down from the 'Off' position. It has a 'flick wipe' operation going up from the 'Off' position. However, if you hold the wiper stalk in that 'flick wipe' (i.e. up) position for at least two seconds or two sweeps of the wipers, it will set the wipers into intermittent mode! To switch them off, you simply move the stalk to slow speed and back to 'Off' again.
Whilst talking about wipers, the wiper arms on the Murena have what is now an unusual plastic jaw end into which the blade is fastened. If you fit the conventional Bosch (and probably other makes) blade which has a pin across the centre then this will clip into the jaw and work fine. No other adaptor is needed. Use 530mm (21") length blades for optimum clearance without excessive motor loading. 550mm or longer blades may fit but the additional blade friction will load the motor and slow the wiping speed. I find Rain-X is very good and means you need the wipers much less anyway!
- The air from the Murena interior vents is always warm even when I select full cold. How can I rectify this?
The latest cars have 'air blend' ventilation systems. Air blending means the heater matrix always has the full coolant flowing through it, and for cool or cold air inside, the airflow over the matrix is progressively shut off. Earlier cars (say seventies and before) had a control tap to limit the coolant through the matrix and for cold air it was shut off altogether. The Murena uses a mixture of both. So there are two possible causes for this fault. The first is that with age the heater tap, which should stop the flow of hot water through the heater matrix when set to full cold, is still allowing hot water through. If this is the case then you need a new tap. The second and most common problem is that the set-up adjustment is wrong. The problem here is that everyone sees the cable from the interior lever on to the tap and tries to adjust it to turn it off fully. What they miss is the fact that a second cable goes directly back from this tap to a flap inside the heater box, and if the flap closes before the tap, it will stop the tap from closing fully. I would say almost every car made was set up incorrectly but once the setting is corrected, the tap will shut off and you will get cool air inside - as cold as it is outside anyway! So you MUST adjust the setting so that the flap and tap close together first, before adjusting the cable from the interior lever.
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This was last updated 5th April '21