annoying missfire!

[akaax]

My girlfriends polo 1.4 cl has a very annoying slight and intermitent missfire, this seems to happen mostly when trying to accelerate up hills. I have changed the plugs, rotor arm, cap and leads (start with the easy stuff) but still does it. It happens if the engine is hot or cold. Any ideas greatfully recieved!

[mr rugby]

I have a 1.4cl and had a similar problem last week.
I had a magnet marelli distributor with the black cap. The other version is a bosch distributor with a brown cap.
While i was changing the rotor arm i noticed a lot of side play on the shaft that the rotor arm sits on. After removing the white dust shield (clipped inside the body) it exposed a round plate that contained the electronic hall sensor ( this is what pulses the low tension side of the ignition system and replaces the old ignition "Points").

Now this shaft is supported on this plate with a bush type bearing.
it is held in place with spring arms.
My shaft had become excessivly worn within this bush, preventing the rotor arm from centralising and causing a missfire.
I removed the plate and tried tightening the spring arms using a suitably sized socket placed over the spring arms and gently hitting with a hammer to squeeze the bush bearing a bit tighter. I then lubricated the bush bearing with oil.

Mine was so worn that it only lasted a couple of days. I have since replaced the distributor.
You may want to check yours, but even if you find it is ok, you would be wise to lightly lubricate this bush type bearing to prevent wear.

mr rugby

[akaax]

Thanks for the tip, i shall have a look and see if its the same problem you had. Will have to wait till the weekend though, so it will probably be raining! By the way how much did your new distributor cost?
cheers

[mr rugby]

approx 50 quid incl vat


mr rugby