Hello all,

 

New to this forum but have picked up some great advice and info here so thanks.

 

I have tried to research this problem all over but can't find an exact copy of the error. Sorry if this has been discussed before.

 

On my way to work on Thursday my car begaun to missfire very slightly before gradually getting worse. Being just half a mile from work i drove on very carefuly but by the time i arrived i was down to 3 cylinders.

I have checked under the bonnet and by disconnecting the leads from each coil pack i derived that diconnecting cylinder 1 (closest to battery) made no difference to its lumpy running so its obviously a problem in that cylinder. I have been out and bought a new bosch coil pack and a new spark plug but that made no difference. I have since tried switching coil pack and spark plugs around but it is allways the same cylinder.

The spark plug that was removed from the problem cylinder was coated in un-burnt fuel so i am presuming that the injector is ok?

 

This is now the lmit of my knowledge of this engine and  so I cannot diagnose the problem any further than this.

 

As a quick history of the car, i had an egine replacement just a few months ago by Skoda following a cam chain tensioner failure. They advise me that they swapped the ancilleries over from the old engine so they aren't covered by the warranty. But i am starting to wonder if it could be a faulty valve seal or head gasket or something similar.

 

Anyone's input would be greatfuly recieved.

 

Thanks,

 

Dave.

My first thought Is the injector. A wet plug is no indication that the injector is delivering the right quantity of fuel for combustion. A scan might show more.

 I have been out and bought a new bosch coil pack and a new spark plug but that made no difference. I have since tried switching coil pack and spark plugs around but it is allways the same cylinder.

The spark plug that was removed from the problem cylinder was coated in un-burnt fuel so i am presuming that the injector is ok?

 

Injectors,coil packs and spark plugs are Ok, you did a great job with switching them all around.    :strong:

But you didn't check voltage in 1st cylinder injector plug  

Sounds like defective cable/wiring loom.  

Edited 21 February, 201511 yr by IngusSeflers

Thanks for the feedback guys.

Think i'll start by checking the voltage, then move on to the injector.

 

I recall there being about four pins in the coil pack connector. Does each coil pack have a constant supply and a signal wire or just a pulsating supply? Sorry if this a dumb question but its a bit of a steep learning curve for me on this one. If its a constant supply, which ones will be the 12V '+' & '-' Also in this case, would there be a comman live supply to all coil packs or is there a seperate supply for each? This will help me track down any wiring faults.

 

I admit it may be a case of getting it checked out by a garage if this doesn't solve it.

 

Thanks again