I have recently aquired a Peugeot 205 XS to use as a daily car. Good fun little car with a big carbed 1.4 which goes suprisingly well. However, it appears to have a problem which mainly occurs after sustained revs at high speed. I.e. Motorways!

After a while of perfect running the car will loose all power yet it will still idle fine and on one particular occasion the other day it will just about run at absolute full chat (which allowed to limp two junctions of the M1 for it to give up on the slip road!)
Once it has started to do this it will not run properly again until it has been left for a while and cooled completely.

Has anyone got any ideas? The plugs, rotor arm and dizzy cap have been replaced and the carb (32/34 solex) appears to do its very well when running.

Any ideas much appreciated,

Cheers,
Andy

i had a 405 mi16 that after/during a run would loose all power, it was the lamba sensor on the exhaust I think gav on here got a similar recent on his seat leon,

http://locostbuilders.co.uk/viewthread.php?tid=46184&page=1

maybe it is the "floating" in the carb. Maybe it do not work at the right height so inside the carb you have little fuel. If you fix "floatin" to work in a hight position (Just a little) maybe you solve the problem.
BTW: if the problem is on floating hight, the car within a minute would retourn to work properly.

I think another cause...
If the car have carb then you have a mechanical fuel pump. This type of pum when it haves problem do not work when hot. So the best thing to do is measure fuel pressure when you have problem. An empirc thing to do ( often works) when you have the problem refres pump with fresh wather, the pump will start to work.
Hope this help.

Sounds like carby problem to me, when you say it just about runs at full throttle it may just be when the 2nd choke begins to open? Mine did this for a while and turned out to be the jets getting bunged up. Worked alright when you wellied it!

As suggested the float may also be at fault.

Good luck,

Iain

Have you fitted a K&N or similar, if so it could be carb icing. Happened to me on an XR2 with K&N i ran a small 40mm tube from the exhust manifold to the filter, enough warm air was pulled in to stop the icing but did not make any noticable difference to the power.

Could possibly be the carb is icing up, a common problem on VW Golfs, Polos etc that have a thermstatic air intake flap . Thermostat fails so carb only draws cold air , carb freezes , engine loses power and driver pulls over , lift bonnet , no visible problem , gets back in and drives off normally for a few miles happened to me on way to SVA with crossflow engine with K&N filter

Must learn to type quicker!

Cheers guys,

I dont think its icing as the standard inlet system/airbox is on and the duct from the exhaust manifold appears to work.

I have heard that there is a possibility that a vacuum is building in the float chamber. Does this sound possible?

I may try and get hold of another carb to see if this solves any problems.

Can't remember if the Peugeot has a vacuum operated sensor for the pre heat system? If it has then just disconnect the vacuum pipes and join together . If problem goes then that is your answer. Might also be worth checking fuel tank vent, if blocked it would cause vacuum in the tank and possible fuel supply problems. Try driving with fuel cap off? but be careful