16V misfire and sparks from leads

[Ade244]

My 16V has developed a really bad misfire in this damp weather.

First I thought it was the dizzy cap as this was lit up all over with sparks. I took the cap off cleaned it up and put it back on.
I didn't find any oil in the dizzy (searched the posts on this subject) but I had some water mist on the inside. Now the misfire is still there but not as bad. I can see the leads breaking down in a few places across the rocker cover, and sometimes at the coil also. It's like a light show under the bonnet but the dizzy cap now is OK with no sparks. The misfire seems to clear as the revs go up.

Before I throw new plugs leads,cap, rotor arm at the thing, have I missed anything obvious here? 

I've only had the car a few weeks and this is probably the first load of damp weather it's seen with me. Is this a common prob on the 16V? From the history I had with the car it only had leads and a new coil just over a year ago.

Thanks for any advice
Ade

[russ-vdub]

replace evrything..you'll have to do it soon or later anyway.. or slap some insulation tape around the part where its arching to stop it shorting out

[Ade244]

Thats the strange thing thats got me confussed. It's breaking down all over the place! First the cap then the leads and coil.
It's like all the leads are dancing in blue sparks

[russ-vdub]

make sure all the leads are pushed down tight on the sparks, the cap and the coil.. could be a loose lead.. i had this one mornin (hungover) and was driving down the road and didnt even notice my car was blurppin everywhere.. pulled up, opened the bonnet, sprarks everywhere, got shocked bout ten times (still hungover remember).. pushed all my leads down on the plugs.. presto! drove home

[DarnPB]

It sounds as if your leads are a little past their sell by date. Leads go porous after a while and let the condensation in, and water conducts electricity very nicely. A temporary fix is to coat the leads in varnish or nail polish. But really the only fix is to replace them. OE is called for but be prepared to pay for it. Also a good idea to replace the dizzy cap and rotor arm too for peace of mind. Then you know its right.
May be a good time to upgrade your leads for some thicker, higher performance items. These usually come in a kit and you cut them and make them up yourself.

[monzablue16v]

GSF do some good leads made by Hella for about £35 oe ones are nearer £95

[russ-vdub]

do leads really make that much difference?

[Ade244]

Defo my leads are shot, they shouldn't break down and arc even if the plug gaps are out I reckon.
GSF list a £30 set and a £59 best quality set. I'll go and have a look on the way home tomorrow.

I hope that cures it, i've never seen anything like this in 20years of playing with cars. The 16V must have a higher volts output from the coil or something.....

Cheers

[tobz.]

Yeah I'm pretty sure the 16v does have a higher power ignition circuit, I remember reading somewhere once that that was the whole idea of the beesting aerial. They had to move the aerial to the rear of the car to stop all the interference.

Go for the best quality leads you can afford, I've bought cheap in the past and the fit/quality has been really poor. I've got the best quality ones from GSF on my car at the minute and they are pretty robust, from memory I think they are BBT leads.