Fiesta 1.3 misfire

"DJ" wrote

I know you say you've checked the resistance, but these are classic symptoms of the HT leads starting to break down. It may be that when you remove them from the plugs, and apply your test meter, that you are temporarily improving the contact through them. Have they ever been replaced?

Vince Thanks for the reply. I don't know the history of the leads but I used a spark checker and the sparks jumped a 10mm gap. That's why I haven't changed them, like you I thought of them first. I may just replace them anyway. Dave

Also check the plastic plug that's situated in the centre of the air intake because they melt.

Andy

What a completely pointless tool. How big a gap they jump in normal air is pointless. All it tells you is that power is getting to them. A completely knackered plug can still produce a spark outside the engine and you can't go by the colour of the spark either as it tells you nothing of their performance under typical working pressures.

Plastic thing? Its actually the Air Temp Sensor. And yes they do, which does throw the fuelling completley off.

Tim..

I'm not quite sure that Plastic 'plug' equates to plastic 'thing' but I'm sure he'll find it whatever ! ;-)

Andy

Conor Not sure I agree with you on this one mate. I used to be an outboard motor maintainer and the manufacturers provide this tool and specify its use to simulate the load by providing a bigger gap but not under the pressure generated in a cylinder. I'm going to change the leads just to eliminate them. Thanks Dave

"DJ" wrote .

My own point is that the leads may be breaking down, but as you remove them from the plugs and use the spark tester, you are altering the angle at which they sit and this may temporarily improve a poor connection. As you say, I think it's wise to replace them anyway, especially as they aren't expensive for this model of car.

Clean the multiplug electrical connectors under the air filter - the pins and sockets corrode.

Si

Fair point mate. Very interesting website as well. I managed to go E Germany before the Iron Curtain went. Dave

"DJ" wrote ]

Cheers mate, the website's very amateurish but it was a fascinating job and lots of people have commented favourably on it.........I never got to go there during Communist times- my first trip was 1994 but I would have loved to have visited before- have driven through the old E/W German border many times too. No doubt you will be familiar with the "fun" of driving for a few hundred miles over cobbled roads.........Ooh, me bum!