MatraSport Forum

Hello everyone, I just bought an '83 Murena and I think they are just wonderful cars.  Mine needs some fixing in order to be driveable.  It has a 2.2 engine and 2 Solex carburators.  For some reason when i accelerate it dies completely.  I have checked all the hoses and everything seems fine.  Any suggestions.

Regards,
Juan

Hello  :)
are you going to post some pictures?  ;)

Did you mean that when you accelerate pulling full throttle or everytime when you want to accelerate?

Hello Juan

Welcome to the forum and congratulations on the purchase of the car!

To help with your problem, it would be best to know some more details, as Michal mentions. I would also like to know the mileage on your car.

It sounds like you have either a genuine Murena S 8) or one that has had the kit fitted. A few things can go wrong with sidedraught cabs, particularly tohe Solex'es, which are unfortunately not as well built as the similar Dellortos or Webers.

But I think your engine is sucking false air in one or more cylinders.

To find out which, I suggest you do the following: Adjust each idle mixture screw alone. Give it a 1/8 turn out and check if the engine reacts to that. If it speeds up, give it another 1/8th of a turn. If it slows down, turn it back 1/8 so it speeds up again. Do that until idle speed starts decreasing. Do that for each cylinder in turn. If idle drops too low or too high, adjust the idle screw so it's back around 1000 rpm.

When you feel it's running correctly on all four cylinders, shut the engine off and turn each idle mixture screw down to the lightly seated position. Count the number of 1/4 turns carefully, and turn it back again to the position you found it in. A 1/4 turn difference between the cylinders is not uncommon, but if there's more on one cylinder, then you know where the problem is.

If the problem is related to one of the two outer cylinders (where you have vacuum pickoff's on the manifold), try blanking them off and repeat the adjustment above. You could have a small leak in one of them.

If there is a leak, it could be the manifold gasket that has been sucked in. Replacing it will not harm anything, but you could try tightening the nuts first as removing the carbs completely is a bigger procedure.

Another possibility is for the brass bearings in the throttle spindles to have been worn down. I think these carburettors have brass bearings (and not ball bearings like the Webers and Dellortos), in which case they will wear down with age and use. If that's the case, then carbs are difficult to repair, unfortunately :(

Another forum user suggested pouring a small amount of thin oil around the suspected vacuum leak - it will be sucked in, and this will initally seal the leak, and the engine speed will change (probably drop). After a while, the oil will all be gone, and the leak will be reestablished, and the engine speed will be like before.

Third possibility is for the carbs to be in need of a good cleaning. If the car has been standing for a long while, the fuel will have dried out. Petrol leaves a chewing gum like black substance, which can block the little passages in the carbs and jets.

I suggest you do some obvious checks, and then go for a complete stripdown and rebuild of the carbs. If you find that they have been wornd beyond repair, I suggest you take a look at eBay for replacements - Solex ADDHE's are frequently offered (with sellers usually claiming they are in good shape) and sells quite cheaply. You can then move jets, emulsion tubes, chokes and aux venturis over from the original carbs.

I hope this helps, please let us know about your progress! And I'm sure we'd all like to see pictures, and know more about your car and you.

Best wishes,
Anders

Thank you Michal and Anders.  To answer Michal's question it dies as soon as I accelarate.  It won't speed at all.  It had been sitting for two years. 

Let me tell you a little bit of history about this 1983 Murena.  I bought this car from the original owner that bought it new and had it shipped from Germany.  I live in the states.  The owner bought his first Murena in 1981 and had it shipped to California.  He could not get title to the car.  In order to get title for the car, the car had to be crashed and tested by the department of transportation.  The autorities would give him a certain time to get registration and if he didn't they would confiscate the car.  He would wait until the last minute and then he would ship the car back to Germany, sell it, and buy another new Murena.  He would then ship the new one to California and do the same thing over again.  He did this 3 times (everytime buying a new Murena) until he got a guy that was able to get the title for it.    Since he has a manufacturing company in Texas, once he got title for it, he had it shipped to Texas.  Now the car has a legal Texas title.  I know this is true because I work for him.  He wanted this car to race it.  This Murena that I bought came with the rear and front spoiler and bigger tires on the back.  It has been sitting for many years.  The last time he turned it on was in 2006 and it was only for a short period of time because one of the carburators was leaking fuel.  Before this it had been sitting for at least another 5 years.  The good thing is that it was always stored in a warehouse.  I hope I get it running but it will be hard because I am not a mechanic and the people that are haven't even heard about Matra.  Not even the local suppliers know what it is!!

Juan

Hi Juan

You aren't the only Murena owner in the states, but there aren't many. A guy from Japan recently brought his Murena with him and now lives in California (but I think he started on the East Coast). Thanks for sharing the story about the car! Your boss sounds like a real nice guy! ;)

Since you mention that the carburettors are/were leaking fuel, I'd point to them as being at fault. They have to be stripped, cleaned and rebuilt. Anyone knowing webers or dellorto carburettors should be able to do this for you, if you don't feel like doing it yourself. Alfa guys might also know the Solex'es.

This guy in California was recommended by the Murena owner above, and seems to be a one-of-a-kind personality. He's even a Murena owner himself. I know its a long way from Texas, but you might consider shipping the carbs off to him:

http://www.studiotimecapsule.com/

- Anders

Another possibility you might want to consider is a leak in the vacuum takeoffs from the manifold.  There are two, as Anders mentioned, one for the brake servo and the other (via a reservoir in the front right-hand side of the engine bay) for the pop-up headlights.  Both run from the back to the front of the car and the piping may have deteriorated while the car was standing

You are very right, and they can really make a mess of things. Especially on a sidedraught configuration, where you will have one or two cylinders running very badly. The single carb is not that sensitive ;)

Hello, any pictures (or diagrams) of the vacuum.
Thanks

I don't think we have any on the 'net. There's an online version of the workshop manual on www.espace-murena.com, but it's in french and incomplete; and this particular part is not covered :(

But it's not that complicated and the vacuum is probably working all right - since you are looking to fix an engine running problem, I suggest you just block off the vacuum takeoff's (except the distrubutor advance). Two short pieces of 9 mm hose with a 10 mm bolt in the end can be very useful :)

I have tried and tried to get the car going but to no success.  I removed both solex carburators, cleaned them, but still no luck.  Should I just switch over to a one carb setup or does anyone have a set of good solex for sale?  I have followed Anders blog on the two setup carbs and it seems very dificult so I think that the best solution for someone that has very limited mechanical knowledge is the one carb setup.  I hate to give up on the two carbs. 

I don't think you should switch to a single carb. It most likely won't help! Remember that they are already tuned to the engine, which is not the case with mine! Also, remember that when my carbs really troubled me, it wasn't the carbs at all, but the ignition coil that had failed!

So I tend to think you have a problem elsewhere.

Here's a few things to check (off memory):

- Compression
- Ignition coil, leads, plugs and distributor rotor and cap
- Ignition module, pickup coil in the distributor (is it firing?)
- Distributor timing
- Do the carbs get enough fuel in the float chambers? (I don't recall, but I think the Solex carbs have an inspection cover like the Webers, where you can get a look down the chamber to see it)

Try to avoid using the choke mechanism, as it easily floods the engine. With a good ignition you should be able to get it running without. It may take some craking until compression has built up and fuel condensation in the combustion chambers stop, but it is possible. Give it just a light opening on the throttle the ease compression build-up during cranking. A short snap opening will activate the acceleration pumps and give a squirt of extra fuel. This might aid starting, but could also flood it if you give it too much.

If you're unsure about how to check either of the above points, let us know and I'll be happy to "talk you through".

- Anders

RESPECT!!!!!! :)

Just trying to load some pictures but it seems like I can't.  Does someone have a good set of Solex 40 ADDHE carbs?  Someone local told me that I could buy a simple ford or chevy carb and modify the manifold so that it could become a one carb manifold.  I would hate to go that route but I just can't have it sitting around much longer.  One question, if I change to the one carb do I have to modify anything else?  The manifold has an opening for the thermostat (?) and a pipe runs underneath where the manifold sits.  Is this anything I should be concern about if I make the change.  What about the airbox that sits in the middle just to the right of the fuel tank.
thanks

Welcome to the forum. You will love the Murena.

I don't have any experience with the solex carbs, but  I once had a 442, where the accellerator pump in the carb had a bad piston. With no squirt of fuel to compensate for  the butterfly valves opening, it died. Just like you describe. So if the solex has a similar setup, you may want to check that pump.

Juan, forget what the local guy told you, it's just speculation. If you want to try a single carb you should fit the original manifold on the Murena and an original Solex 34CIC or an equivalent Weber. There are plenty of these manifolds around and they bolt straight on. Keep that in mind, but don't go down that route yet.

I'm willing to check your carbs. You will need to ship them to Europe and cover my expenses with shipping and possibly new parts, but I'll enjoy spending time on cleaning and checking them thoroughly. I'll tell you if they are worn beyond repair, but I would doubt so. But if they are, I can help you find replacements or a single carb on manifold.

I understand you want to ride your car, but be patient - it will pay off in the longer run!

There are 40ADDHE's on eBay from time to time, so we should be able to find replacements for worn parts.

/Anders

Thanks Jon and thanks Anders for the offer.  I am really excited about driving the murena, specially now that tax season is almost over.  I have a 1963 galaxie convertible which is totally opposite of the murena.  Anders, just send me over your address (you can e mail me at jdlfverified@aol.com).

To the best of my knowledge Delorthoes or webers will fit the "S" manifold just as well! they should be easy to find.

If you decide to go for the single carb, I have a couple of spare manifolds... and even a carb (though it will need a MAJOR overhaul).
But I would recommend you stick with the twin carbs.. sounds a lot better.

Ps: It has been mentioned... but I would really recommend you check all parts of the ignition system.... especially the coils have been found to cause trouble.

Let's see. I'll give them a good checkup when I receive the carbs from Juan. If they are worn beoynd repair, we'll have to decide on replacements, but this car hasn't run that much, so they are probably just in need of a through cleaning.


Agree, and the twin carbs are also preferable for the sake of originality.


Again, I agree. Regarding the coil, you must be thinking about my troubles...! ;) I don't think coils are particularly problematic, but since a new coil is relatively cheap (and Juan should not have problems finding one - just pick one designed for electronic ignition), it's a good idea to replace it along with new plugs, distributor cap and rotor.

Another item that has given me problems is the fuel pump. Juan is probably still running the mechanical fuel pump, which is fine and reliable, so he should not have problems there as long as you can see fuel being pumped up into the filter when the engine is cranked.

/Anders

When I ahd injection fitted It was found that my could was all but gone as well.

I can't seem to attach pictures.  Help!!!

Try uploading the pictures to a 3'rd site such as "photobucket.com" and then use the link feature to post them here.. that works for me :)

Hello Juan,

Can you give us the VIN (full 17 digit chassis number) please.  It starts VF853C...  This will tell us exactly what version Murena you have, since if it is a genuine 'S' there is a little more to the carburettor and vacuum system than other models.

Second, have you contacted the NAMR (North American Matra Register)?  There are guys with various cars all over the States, and I know there are some in Texas, and with a problem like yours, it would be much easier with someone who knows about European cars with carbs. to have a look at it directly than expecting accurate 'long range' remote diagnosis!

From what you have said so far, I can't even say whether your fault is actually with the carbs. or not.  So spending lots of money getting them shipped about to be checked and possibly rectified when you don't know for certain that it is the carbs. seem pointless to me.  When you say you can't accelerate, I think you mean you can't rev the engine with the car stationary in neutral, is that right?  Because to me saying 'you can't accelerate' means you are driving the car at a steady speed but it won't pick up and accelerate, which is a different thing entirely.

Also if you did change the twin side-draught carbs. for a single, twin-venturi down-draught carb. is not that simple and yes the inlet manifold is water heated for the down-draught carb. where it is not on the twin side-draught set up, so you need not only the correct manifold but a different water pipe under the manifold and two hoses...

However, going back to the problem, if you try to rev the engine and it dies, it could be a number of things, like ignition coil, amplifier, fuel feed, float levels, restricted inlet, etc. and it would be unlikely that both carbs. would be faulty or even in the same way, so if one was right and the other had a problem, you would not get the engine dying so easily.  The fact that yours does suggests the problem is not with the carbs. at least not entirely.

Contact me directly (roy@matraclub.org.uk) if you want more info. on NAMR or check my website.

Roy

When typing in your post, there is (should be) a link called "Additional Options..." just below the entry box. If you click that,  it should reveal several options, - among them a field called "Attach" where you can select a filename from you harddrive. Having done so, the picture should be uploaded and attached to you post. Be aware that it will now take longer for the post to commit, as the picture has to be uploaded first.

Let me know if you still can't make it do what you want.

/Lennart