MatraSport Forum

I think I need to check my coil, distributor, and plugs...

Murena had been standing still for about four days and was running on three cylinders this morning when I started her to take the boys to school, but it cleared and we made it well in time before the bell rang :)

BUT THEN hell broke loose. It was a bit reluctant to start when I came out to the car again, but finally made it, but only a short while: 400 meters further it stopped when I let it idle to get out on a crossing road. This time it was even more reluctant to start, but made it, until the first red light. Stop again. Got it back running with a couple of BANGs! when the petrol in the exhaust ignited - did people look? yes! A few hundred meters further down the road the queue for the next red light started... and she stopped :(

A few minutes, ignitionless cranking, and bangs later she was back running on the choke, and I had to keep her on that all the way in today to get the idle high enough ???

Did someone mention WD40? Yes, that's a first. Don't know why I don't have a bottle in the car with me, but most likely I won't have any problems going home, now that it has had time to dry out well after the morning drive.

Cheers to all,
Anders  :)

Sounds like a fun time. Sorry to hear about that.

I take it that it was raining and damp in Denmark this morning? The Murena engine bay shouldn't get very damp as it is sealed on all sides apart from underneath.

No you are right, but when the engine starts heating the air in the engine bay, the hot air will condense on the cold surfaces in the bay, and the ignition coil is probably one of those places...

- Anders :)

My ignition coil died recently and there was no warning, the car just died.
If it was running on 3 pots, then the most likely cause would be the distributor cap or plugs. If the leads were dying, they would break down at higher revs.

Been there done that.
The coil on my "newly acquired" 1.6 in 1995 was *very* rusty, and the spade connectors were corroded so thin that I was concerned they would brake off. SO, I ordered a brand new coil - which came in the original Talbot box, with the correct partnumber and all.

Fitted the coil, - it looked healthy and good - engine fired in good spirit, and I set off from Reading/UK towards somewhere north of Sheffield.

Made it as far as 20 miles south of Sheffield, where there was ground fog, and the car simply died,  and there was no chance getting any life out of it.

Hours later, I had roadside assistance from no less than Roy Gillard (whom I was intending to meet up with at a MECUK meeting) and before long, the coil was pinpointed as the culprit.

But where does one get a matching coil on a friday evening ??

However, my apparently guardian angel Mick Ward had followed Roy, and from the vast vaults of his Simca-1000 he pulled out a coil, - which worked beautifully!   THANKS MICK!  - AND Roy!

In fact, that coil was still on the engine when I 4 years later had the car converted to the 1.9i

Sometimes brand new spareparts are as much likely to brake down as the old ones, - primarily because they themselvces can be as old as the car, I guess.

Anders: - in the light of my recent Peugeot-106 problem, I assume you have checked the ignition leads and their connection to the distributor ?
(I recently found out my P106 runs MUCH better with all 4 leads connected :-)   )

Naa, not really, it used to work fine, so I guess there wasn't any need... until today. "Wror wror wror BANG wrror wroo BANG wrooorr BANG!" :D

But it *did* run, eventually. Besides, I wasn't kind to Murena: I left her standing still for four days, outside, on the road. Gave it a wash Sunday evening. Fired it up Monday morning. Drove less than 2 kms and then left her for maybe 15 minutes. With humidity somewhere around 80%, a lot of damp can find it's way into a rusty coil, so it isn't strange that that ignition did not work, I think.

Going home was no problem (and my! she's running well on those Pirelli/Conti winter tyres!), though idle was lower than it was last week. I don't understand that!? But we will see.... I didn't manage to fix anything this evening as I am just too tired, so I'll take the J117 tomorrow :)

Spare coil (Roy supplied one with the car!) and four new plugs are ready and waiting on my workshop desk, and a new membrane for the accelerator pump which is leaking a bit should be on its way from Simon too, so I might as well wait and do it all at the same time. I'll check the distributor, then. I've got Saturday scheduled for some work in my father-in-law's garage: Getting that coil screwed out and back doesn't look easy on a 2.2, so it's probably better to wait, unless it breaks down completely in the mean time...

- Anders

to me it sounds like a failed sparkplug, lead or distributor.
The carb is quite obviously supplying all the petrolfumes is need to, it is just not ignited everytime. 

Take one thing at a time, - I'd start with the sparkplugs, - then leads (if possible), distributor, and then maybe the coil, since you have one on stock.

However, I don't see the coil as a very likely cause for this behaviour, - a "tired" coil would only fire occationally and certainly not at higher revs. In my experience a failed coil will hardly make any spark at all. But there may be strange ways coils can fail?

/Lennart

Anders, I think you are running a single Solex carb.

I know you have fuel getting into the engine and it seems like an ignition problem, but imho it could well be the carb.

It just sounds too familiar to what my original 2.2 used to do regularly until I threw away the Solex and fitted a single Weber...and never looked back.

Sorry to hear about your troubles.

I sincerly hope you get it fixed asp.

Lars Bjørdal

You are right, Will, I am running the single Solex 34CIC and they aren't the best.... certainly not compared to a well jetted new Weber. But I sincerely think it's okay and with all the moisture that I can see builds up on the rear window when I treat the car like I did Monday morning, it does'nt take much imagination to get an idea about how it must look around the coil and leads in the otherwise hot engine room.

The unstable idle could also be the ignition, but with this particular cam (Holbay with its 70+ degrees overlap) idle will never be entirely stable ;-) Acceleration at 3000 rpm+ is, however!! :D

Thanks for all the positive thoughts I'm getting... Saturday in good daylight, I'll go through it all and let you know what I find!

I refuse to belive that the ignition components are THAT vulnarable in the murena!!
The midengine should be an ADVANTAGE! regarding exposiure to moisture

The engine room is not ventilated as well as on a front engined car where there's usually ventilation both front, up and down, and sides. This means that hot air from the engine is trapped. Hot air can absorb more water than cold, so while the engine is warming up, the air in the engine room will absorb water from the outside air and contain more water per volume than the cold air outside.

Since the chassis will always be colder than the air in the enigne room, moisture will form on the chassis sides of the engine room as it does on your glasses when you come inside from the cold. But as long as we keep adding heat from the running engine, and move the car forward, the continous airflow around the engine will remove most (all?) of the moisture. But when the car is stopped again, ventilation is effectively blocked except for the small ventilation hole on the right side of the engine room.

The now cooling hot air is trapped and the water absorbed in the air has to be released as the relative humidity gets closer to 100%.

The coil is fitted on the chassis and I think it and the ignition leads will be one of the first places for the water go. Others will be the carburettor, rear window heater relay and all the vacuum pipes. All these things are significantly colder than the engine.

So, while you can refuse as you want to (it's a free country!), I obviously don't agree with you, Krede :D

- Anders

PS: What's happening to your mail address?

I won't dispute the thermodynamic facts here (since it makes sense), but having said that, I would expect the heat to evaporate any water quickly, and thus disappear by ventilation or through the engine intake.

I have never regarded my Murena enginebay as a particularly wet or cold place.

Lets see what you find in the weekend - poor electrical connections don't need much pressure to brake contact alltogether. Be it through water, corrosion or physical distance.

/Lennart

Sparks replaced yesterday, the other parts inspected and looks okay, but coil is still rusty and moisture could still enter it under bad conditions. No change noted, but carburettor *is* a problem as it leaks petrol from the accelerator pump fuel line (not the pump itself, but the line where it goes up to the upper part) - at least on the outside, and apparantly also on the inside as it had developed a good bit of run-on. It's the O-ring around the ball valve that isn't sealing, and the gasket apparantly can't take the pressure. I'm going to take it apart again in the weekend.

Will is right that the Webers are better built, but I still beleive that I can get my Solex to run well.




I'll keep you posted, thanks everybody! :)

- Anders

I promised an update here...  :)

As I suspected, the O-ring to seal the fuel line from the accelerator pump was part of my problem. Even after I refitted it a couple of weeks ago, it had broken in two. Maybe because I fitted it incorrectly, and maybe just because the O-ring in the gasket set was too large. I didn't care to measure it then, but it was a very bad fit.

There is an inset in the spigot on ball valve, and the o-ring is supposed to sit there. The picture below is from when I did the carburettor the first time and shows how the old o-ring was deformed - it was obviously too large, as the ones I have fitted. This time we measured the spigot and hole, and apparantly it is designed for an O-ring with 2.5 mm inner and 5 mm outer diameter. The smallest one I could find yesterday was 3/6, but I hope the 1 mm oversize can be compressed to shape without damaging it. In any case, it went in well and seems to be sealing now - but I'm obviously going to keep an eye on this, and if it starts going wrong again, then I'm going to look seriously for a correctly sized o-ring.

But whether this has been the source of my problems remain to be seen, as even if the o-ring is not sealing, fuel should not be able to enter the venturi. As can be seen on the second picture, any fuel spilling out on the inside would go back to the float chamber. I actually only realised that after writing this post (I've edited it now).

So I will still keep an eye on the coil, but didn't care to replace it Saturday as I didn't have my rubber-arm-kit with me ;)

Hey come on! - you have small kids - at least one of them even mechanically inclined! :-)

But since you originally (in this thread) managed to keep your engine running on the choke, that takes the suspicion a bit off the coil... 

/Lennart

You must be thinking of Troels... :D

Blimey he's got strong fingers!!

A few more thoughts and facts...

- Fuel consumption is somewhat too high, only about 7 km/l (16-17 mpg)

This is partly due to the fact that I do only/mostly short range city driving, fuel was leaking out of the carb with the o-ring broken, there seems to be a small leak around the accelerator pump, there may also be a very small leak on the fuel pump, idle jet has been set a bit too rich, and I tend to like the sound and acceleration when flooring the pedal around 3500 rpm ;D

I will replace the fuel pump with an electric pump as soon as I find time to get me a 90 degrees drill head to make the holes in the engine compartment to fit it on (it will be fitted in the fuel tank side) - and to do the job of course ;)

During January I'll take the carb out again to replace the accelerator pump membrane and to inspect the o-ring. Replacing the accelerator pump membrane can't be done in the car as the fuel in the float chamber will spill out when I remove the membrane. So it has to be dried out first.

- Running a fast-road Holbay cam as I do with the relatively large overlap of (I think I recall) about 90 degrees, means that there's a risk that at low rpm (especially cranking!), exhaust gasses are pushed back up into the inlet manifold. This is probably part of the explanation of the starting problems I had that day with the many explosions :)

This is not a problem in general, the engine runs very well even in low rpm once it's warmed up, but when it's really cold, it needs a well accelerated idle to avoid dying on me.

Roy is an advocate of this cam and with the experience I have with it so far, I agree with him as it really adds to the fun factor of the Murena. The performance of the cam probably depends a good deal on the exhaust side to create the necessary suction to get the actual performance and avoid exhaust being spit out into the inlet, whereas the inlet side is much less critical and may even benefit from the single carb setup that I have.

- I haven't had any starting problems sice that day, so I might just keep my spare coil in the trunk for now.

- Sunday when I fired well under the car on the motorway it acted odd when I turned off, as it was slightly reluctant to run and idle ended up being around 2000 rpm... carb ice! It cured away after a few minutes, but tells me that I should find a piece of aluminum tubing to take the inlet air from the exhaust area (the automatic switch in the inlet isn't connected).

But with black ice all over in our neighborhood this morning (!), I decided to take the Espace though, so Murena is standing still today 8)

Yep, - that does deflate a lot of the talk about poor ventilation at the top of the engine.
When driving, there really IS a lot of fresh (and in DK currently too cold) air up there - so the added temperaturedrop of evaporating fuel becomes a problem. Boy, do I remember that :-)

/Lennart

Well Anders if your main concern is fuel economy you should not be driving a Murena but something like a Polo HDI.
With your Holbay cam with big overlap (under some conditions) part of the unburned gas must be blown out through the exhaust, resulting in bad mileage.

I agree with you Lennart the front side of the engine with the carburettors is not hot as the airflow in the engine room is up the front side of the engine across the top and down at the hot back side of the engine.

regards Hans

Oh no, not a polo!  ;D
Actually I'm only concerned with fuel economy when it comes to keeping an eye on the carburation, and this is something that I've disucssed with Roy: He thinks it can do better and that something may be wrong.


Yes that is correct, but again I'm relying on Roy's experienced numbers with this cam, and they are better than what I get, which indicates that something is not quite right. But then again, it's running well overall, so it may also be my driving style 8) that's making my numbers. I have done only one or two longer jurneys with the car while I've had it (100-150 km), everything else has been 20-30 km per day, and this may really make a difference.


I bought an IR-thermometer recently: After a 20 km drive in the cool weather we have now, I measured the carburettor temperature to about 20 degrees, while the exhaust side of the engine was around 90-100. The inlet manifold is a good deal warmer than the carb because it is heated by the coolant (and the carb is thermally insulated from it), but this only makes the difference more is notable. You are probably right that the airflow means that the front of the engine is cooled a lot in cold weather, but we should not neglect the thermodynamic effect of the (cold) inlet air passing through the venturis, which will cool down the carburettor considerably independently of the rest of the engine block and manifold.

- Anders :)

my 1.9i does 13km/l and can be pressed as high as 14.5 (once!)  if I drive ridiculously careful (=boring) -  which I normally don't.
My 1.6 engine normally did 12, and as far as I remember hardly ever under 11 km/l unless something was wrong. (carb problems)

My 1991 Peugeot 106 1.1 "spare car" does 17 on average, and I have twice managed 18 and 19 on a full tank - (thats 850km on its 45 liters!), so If I want to conserve fuel, I can always take the spare-car, in which my son has fitted a 1600Watt Boss amp and a 8" sub. Thats fun in its own way.   :-)

I'm actually using that for the moment, as my altenator in the 1.9i has gone berserk, and sends 18V to the rest of the car. New alternator (or regulator) goes on next week.


/Lennart

Using the choke any amount of time spoils the milage completely..

Time to revive this thread... I haven't had serious problems like what I had on that day back in December, but I had to replace the ignition coil the other day. Strictly speaking, the coil didn't fail - I broke it myself when the minus tab broke off. Getting the old one replaced wasn't easy - apparantly they designed the car for mechanics with very long and flexible arms, but I got the job done with the help of my son, and there is a good difference in starting and running.

An ignition coild is an ignition coil, and as long as it's working it's good enough seems to be the rule of thumb, but there's little doubt that the 25 year old rusty orange cylinder with copper wire inside was wanting to go on pension ;)

On the other hand, I have also played with carburation, Will kind of suggested that I convert to a Weber ;) but my old Solex 34CIC is in perfect order, the only thing that has been wrong with it has been seals and gasket, and my messing up with these parts. The worst thing to get right is the o-ring in the accelerator pump fuel line, which tends to break if it's not the correct size, and since the size supplied with the repair kit is completely wrong, there almost 100% chance of getting fuel spillage if the gasket kit is used as-is. Like I did. And then it took some five tries to get it right. Details are on http://dinsen.net/murena/carburettor/maintenance (http://dinsen.net/murena/carburettor/maintenance)

Getting this right has also improved the running, especially the cold starting and running on the choke.

So the conclusion is that the problem was probably a combination of the two: Ignition problems caused by moisture, and carburation problems caused by fuel leaking in the carburettor.

I'm happy again :D

Cheers to all,
Anders

As for milage.. I've averaged 7,8 km to the liter since i came home.... :o

To be honest I have newer calculated the consumption during the 10 years I have had my Murena where I have been driven more than 50.000 km.

I try to calculate fun per km instead.

If mileage is important get a Pole 3L of a Smart

Regards Hans

Yahh.. my point excatly
I get alot of 5 mile smiles for my money... and possibly some hearing damage aswell  ;D

You are repeating yourself, Hans! ;)

But I agree, Murena is a fun-car, not one that's fuel effecient. Still, I do understand Krede. He's got his Murena as his only car, so he needs it to be better than it is now, and I think he can do it.

I know this doesn't help in anyway... but this kind of problem was exactly the reason I decided to go for a HDI engine!

I won't have all the carb issues, and the mileage should be around 20-22 km/l without decreasing the fun factor... though the engine might not be as thrilling!

So I figure there's no need to spend ridiculously money driving a fun car, but I will also be using the car everyday!

Just to put you off, Waldo, today while waiting in a junction, a school class stared at my car. One of the boys was even about to get lost from the others because he was admiring it. Now, of course I fired her off in the corner, making lots of noise - just for them.

Now, would you do that in your diesel?

No, petrol for my Murena.

And mark my words: You are going to have loads of problems with your common rail diesel engine. We know these thingies from the Espace's. Great engines, lots of problems.

You can't convince me! :D

- Anders
(PS: Hope to see your car this summer at a Matra meeting, hows the project going?)

Hi Anders...

Well, no the engine tune won't be as lovely, but I'm pretty sure it will be more than fast enough to impress...

I'm not using the same type of engine as the Espace (DCI), and I know these HDI engines well enough to say that problems are few... very reliable and easy to tune infact!

/Valdemar

AFAIK the DCI and HDI engines are both common rail engines built with Bosch components?

Reputation is a strange thing: When Renault put the PRV V6 in their cars, it got a reputation for being very reliable. When Peugeot used the exact same engine in their cars, it was a horrible machine blowing head gaskets. And I'm not talking about the 24 valve head of that engine, it was the same engine.

And to compare reliability: My engine is 25 years old, it has received one complete rebuild and a new cylinder head (overheating, leaking water pump) in its life, and that's it.

I'm not trying to say your project is not worth the effort, I am sure you will have a very fast and driveable car when you are done, and I'm sure this is not the last diesel conversion project we will see on a Murena (I haven't heard about any before, though?), you are just down a completely different road than I am.

My Murena is a classic, and while I'm using it from day to day, I have to acknowledge it's an old car. She's 25 this year! When she was built, I was only in my early puberty! Sometimes, the lumpy cam and difficult choke makes me want to take my wife's car, but when the boys are staring and friends show their envy, I know that my Murena is just the way it should be. It will never be a Porsche Boxter.

I know a family with a strange garage: One London taxi, a 1966 Jaguar, a TR4 and a couple of old english motorbikes. They don't have a single modern car for daily commuting! Don't tell me a 1966 Jaguar is a reliable or fuel efficient car. But this is just the way they like it, and I must admit - I envy them.

- Anders 8)

I disagree - mileage is an excellent tell-tale of any impeeding problems that needs sorting. That is my major reason for calculating the mileage.


I totallty agree, however, that the Murena is all about fun, - the simplest bend can be felt, and the feedback just puts a smile on your face. Also at or under the speedlimit.

/Lennart