just got this focus last week and it has just developed a mis fire...

took plug leeds off and the spark plug holes were full of water and tried that once cleaned water out and i got a right smell of burning plastic...stopped and the lamba sensor wires had touched the manifold and shorted together...seperated then and insulated them and it still miss fires...

any ideas anyone?

 

Fuse blown for the Oxygen sensor heater?
Where's the water coming from?

 

Oxygen sensor heater...where would i find that fuse location?

water was from me giving it a clean...yard at work so dusty.

 

where would i find that fuse location?

 

Fuse 18 (10A Engine Compartment)

Martin

 

well fuse was blown...thanks martin...but still has the mis fire...

once it gets revving its ok,just low revs it has naff all power.

 

also i unplugged the lamba sensor plug while engine running and it made no difference so i'm now wondering if the lamba sensor is goosed.

 

Probably. Have the live data read by someone with the right equipment.
But could also be some water left in one or more connectors.

 

the water was in the holes for the spark plugs and is all dry now.thing is i am off to work in it in morning...got a 3 hour journey to get there too..hate working at different depots!

 

More than likely either that or the wiring has a break where it melted, the lamba are common for problems though so it may be worth replacing.

Martin

 

wires looked ok.still copper colour and looks like i will have to replace lamba sensor in morning...gonna be late for work but what can i do!

 

They can be extremely tight due to the heat, patience is a virtue

Martin

 

well sorted problem...was coil pack and wires on lamba sensor were ok and just both happened at same time..

cars running fine now...

its for sale too lol