1.9 8V - Ht / Spark Issues

[AndyCrom 64]

In a nutshell, this morning I went to start the car and it sounded like it was running on 3 cyl, after a bit of poking around with no tools to hand "long story" I found the problem on cyl 1 (flywheel side) in that if I remove the ht lead from the plug and hold it 2-3mm above then the engine is running fine, yet when I reconnect the lead to the plug the issue returns, if i do the same on any of the other leads it makes no difference, its only on cyl 1 when I make a small gap between ht lead and the spark plug top that it runs ok.

 

My first thought was to get some new leads but in the same thought wondered why if I add an extra gap for that lead, ergo further for the spark to travel that it solves the issue.

 

any ideas welcome

[opticaltrigger 52]

Hi Andy,

Try swoping the plug with the one next to it and see if the same problem just moves over.If it does you will know that you have a plug problem.

That said,and I am not an expert in this field but the ignition coil itself,I belive works on whats called a flyback principle,where the iron core has a very small gap in it which is what is responsible for the very high voltage spike induced in the secondary winding.

It seems in my head possible ( and that dosent mean it's correct by the way ) that the plug itself is defective.By that I mean,the plug could be shorting the charge straight to ground either because of a carbon build up or mechanical failure of the plug internaly.However the extra gap if you like could be serving to induce a flyback effect at the plug itself which in turn may help generate a sufficiently large charge voltage to overwhelm the plug problem.

Now,like I said Andy,I am not an expert in the field and should somone who is feel that Im way off the mark with the flyback please correct me as I do need to know.But I would certainly try moving that plug over and see.

 

All the very best

O.T.