Goodmorning,

I have (visa) engine trouble, and I cannot find the problem.
I already asked several 2cv friends and specialists but still the same problem

Alright, I will start from the beginning:

After the Waggelmeeting the problem started.
during the waggelmeeting I adjusted my float height of the carburettor and replaced the spark plugs. The first +- 80 km, she drove like a super charger and then suddenly she began to stutter above 80 km/hour.

I did a standard VISA check, so replaced sensors, replaced coil and replaced the computer. This did not help, so the ignition parts are fine.

In the low speed is not so much on, and she runs fine idling. So therefore I conclude that the wire tree also is fine.

As I made some changes to the carburettor, it would be possible that this is the problem. I was already planning to replace the foot gasket of the cilinders because it leaked a little oil. When I did this I also replaced the carburetor. Weber instead of Solex. During this action I checked the cylinders and pistons they looked fine, I also checked the cylinder heads they did not leak cleaning fluid....

However, the problem is not gone. Once I drive for 1 minute at full throttle the engine starts to stutter again. The maximum speed drops to 80 km/h and sometimes to 50 km/h.

I think the problem is not in the ignition (I replaced al the parts). To be sure I have replaced the new spark plugs for other new ones.

Still no success.

I recently got an oil filter adapter with oil temp and oil pressure. However, I have only just connected my meters so I'am not familiar with the normal temperatures. The pressure is constant at 7 bar (6.5 with hot engine, idling +- 1 bar)

The engine temperature runs nicely, but runs through to + -105 degrees (this is right since I checked the sensor in boiled water)

I think the oil temperature is pretty high, for driving on a flat road without pushing it (within a few highway km it is 100 degrees). The stuttering is starting at 80 degrees Celcius, so I don't think the engine is getting too hot.

What I checked:
- That the oil adapter plate, if there is enough oil flow, this is no problem.
- If there is a problem with some false air, seems ok.
- I checked if the fuel pomp is the problem, replaced it although it gave plenty fuel.

What options do I have to check/replace left:
- Check the compression of both cylinders, maybe there is a leaking valve
- If so replace cylinder heads
- Spark plug cables (though this odd, given the fact that the problems
at low speed not do)
- Try an other VISA wire tree
- check the fuel connection on the fuel tank (false air, leaking)

Does anyone recognize these problems? and what was the solution?
Who has more tips? All help is welcome!

Hopefully in the Czech Republic?!

Ciao,
PMD

For my 2cents,
Sounds like lack of petrol.
Try fitting a "see thru" petrol filter near the carb, should be almost full of petrol

Runs fine for a minute on full throttle, then starts to stutter and lose power - certainly sounds like a lack of fuel delivery.

For a more definite diagnosis, I'd be very tempted to switch the engine off as soon as it stutters, coast to a halt, and take the lid off the carb to see if the float chamber is empty.

Is there a filter in the fuel line somewhere further back?

Hi PMD,
have you checked the fuel filter which is fitted in line isn't blocked?
I'm not 100% sure if this was a factory fitting, but on our 1983 Visa, it was sited at the rear of the engine bay, just under the steering rack.

When the car developed exactly the same symptoms as yours, I verified that the problem was insufficient fuel delivery by removing the carb lid after the car had stuttered to a halt. The carb bowl was almost empty...

Part of the problem was that the metal fuel pipe was rusting internally, so that was replaced with a 2CV type nylon pipe, plus a new in line filter.

It's been fine ever since, in fact it goes quickly enough for my son to have received his first speeding ticket shortly after passing his test last year. 77mph on a single carriageway road...

ken.

( p.s. slow typing, so Adrian's got there first, but this should be confirmation. )

Just had very similar problems with my 2cv. it runs fine for abit then stops and then fine and then stops (very annoying i know). and it would particually do it up hills!
i replaced the carb everything but nothing seemed to help untill i rang the mr barbour (the master at fixing 2cvs) and he said it was the fuel tank.
I dont know if this is on the 2wds but there is bolt which screws into the bottom of the tank with a copper washer on, unscrew that and see if there any crap in it, all the fuel will have to drain out but you can reuse that.
its the bolt with a hole in were the fuel runs through into the lines up to the carb.
My Bolt was absoulutly heaving with crud and crap and now it runs a treat.
all that for one simple bolt
from the symptons i believe that is the problem.
Let me know anyway!

No, there's no drain on a normal 2cv tank. You can drop the tank and give it a good rinse out easy enough, though.

However, unless there's an inline filter, a lot of the gunk in there will make it's way through to the carb - so taking the lid off will have revealed bits in the bottom of the chamber.

Good idea:
"For a more definite diagnosis, I'd be very tempted to switch the engine off as soon as it stutters, coast to a halt, and take the lid off the carb to see if the float chamber is empty."

what about blowing into the petrol hose to the carb first, if i'm able to blow air in to the float chamber then the petrol level is too low But to be sure it is better to open the carb!

Thank you!

Keep posting ideas!

Allright!

the troubles are gone, it was a combination of two bad fuel pumps and the other carbu had a wrong float height . I did the trick of toomany2cvs and I noticed that the float chamber level was too low. But the level wasn't high enough when the engine was idling for a while. So I modified the float level a little bit. After this the level looks good after a while idling, strange enough the problem wasn't gone on the highway. Still a emptied float chamber when I stopped the engine as soon the problems started.

I replaced the fuel pump and bypassed the fuel filter and after this the float chamber was constant at an acceptable level!! So I was lucky to have 2 bad fuel pumps and 1 wrong carbu! Nice combination.....

But i'm not sure wat is a good level for a Weber carbu? I know that the level of a Solex carbu should be 18 mm (from the middle of the floats to the gasket) but what is a good level for my Weber carbu?

So Czech here we come!

For the record,
this was the carburettor level when I opened it when having the troubles
(see image)

The other photo is a bottle with fuel, I disconnected the hose of the carburettor and started for exact 10 seconds (with disconnected ignition).

With fuel pump 1 I had almost half as much fuel then with fuel pump 2 (I emptied the bottle in between!)

-I think this topic can be closed now!-

Not quite yet,
maybe just time to suggest to twocyli that he ought to find out how/where the muck is getting into his fuel tank, otherwise he will probably need to pull the plug in the bottom of his tank in the not too distant future.

ken.