Ignition lead no 3 blowing off under high Boost/RPM...

[Rowland]

Hi all,

Had a minor niggle yesterday and wondered if anyone has had a similar experience too.
Had my car serviced yesterday and also the catalytic converter removed and a Hyper sports downpipe fitted.
The car felt good and sounded a little more purposeful on the drive home which was good.
Nearing home I decided to open it up on a quiet road when I noticed on full chat the boost was reading just shy of 1.4 bar on the EBC up slightly from 1.3 bar it's usually limited too.
That's odd, would a decat raise the boost I wondered..?
Whilst this thought was going round my head and noticing the revs approaching 8k I changed from 2nd to 3rd. Just before the gear change I feel a sudden loss of power and I'm running on 3 cylinders.
A quick inspection reveals the ignition lead has blown of cylinder number three.
This happened again and then again under the same circumstances.
I tried another ignition lead on cylinder 3, and it happened once again.

The spark plugs were not changed as part of the service although were removed, checked and were ok.

Any ideas what causes an ignition lead to blow off under high rpm and high boost?
I'm yet to encounter this problem before and wonder whether to change / upgrade the plugs anyway or upgrade the ignition leads.
I've also heard uprated ignition leads are hugely overpriced, not worth the money and can increase the risk of damp to the distributor over stock leads?

Any help or advice is highly appreciated.

[Dangerous]

first turn the boost down.....!

[turbomartin]

What ignition leads are you using? This has been known to be a problem with Magnecor leads due to blocked breather holes - if this is the case look in the knowledge base for a fix.

[Rowland]

What ignition leads are you using? This has been known to be a problem with Magnecor leads due to blocked breather holes - if this is the case look in the knowledge base for a fix.

Stock ignition leads.

[raptor95GTS]

is the aprk plug in properly?? Just in case the combustion chamber is venting past the spark plug

[Sidewinder]

Maybe...you've got some air trapped inside the rubber boot of the lead cap, and as the internal temperature heats up, this expands and thus blows the plug lead off?

I can't see any other reason why this would happen.

Well done on the mods, Rowland...another rolling road session coming soon for that magic 300+ BHP?

[JJ]

Rowland,

occassionally this is overlooked, but spark plugs do deform with age, look closely at the plug and you will see the ceramic area passing a little exhaust gas ( top part of the plug ). It might be awkward to see, but the ceramic section fits within the metal chassis of the plug and goes right the way through to the combustion chamber - theres often scaring just where the ceramic interfaces with the metal chassis of the plug.

In a nutshell, its the ceramic allowing a little gas to pass, creating a gas buildup in the spark plug well and blowing it off the lead !!

Change the plug out and your problems should be solved.

[Rowland]

Ok, the problem has been resolved and power is up far more than I imagined!

Firstly thanks to all who offered advice although as is often the case I went through a process of elimination noting all relevant points made in this thread.
The ignition leads were all fine, I checked each and every one in fine detail.
So that kinda' left only the spark plugs.
Whilst out and about this morning I popped into Graham Goode's and picked these up for the sum on £32.00...



....and also some CVL Turbo Octane booster too.

With the new cooler grade NGK plugs fitted, a tank of Optimax + CVL Octane Booster and of course the downpipe I reset the ECU and went for a spirited drive this evening.

WOW!
I cannot believe the difference - simply grintastic!
The 0 - 100 speed is noticeably faster, a lot more than I expected.
I believe it's not 'quite' as torquey as before but when wound up It really is quicker than it's ever been under high RPM!

Noticeably more popping and banging but I expected that, and noticeably more heat build up in the engine bay too. Mind you is was 28°C outside!

So in essence the problem has been resolved, tomorrow I'm off to Rogue HQ to buy a much needed fan kit and I'll probably lean off the boost a little as it's still a touch on the high side at 1.38 bar!
Ironically enough my current drive to work takes me past Nobles every day so I think a RR session is on the cards asap!

Oh and Dangerous Dave, £20.00 says your engine goes bang before mine does matey!

[Sidewinder]

You sure it wasn't that bottle of Becks that ended up in the fuel tank?

[Rowland]

You sure it wasn't that bottle of Becks that ended up in the fuel tank?

Oh Sh!t!