EvoLink G3 intermittent mis-fire

[Stephen Fargher]

Hi,

I have an EvoLinkG3 installed in my Evo 1 rally car running medium boost (1bar) on std. turbo & manifolds etc.  Have had an intermittent mis-fire which I think I have isolated down to being heat related (the car runs Gp. N Anti-lag)

On the weekend at a gravel sprint it only started mis-firing at the very end of the 1st run but around 2/3 through the second run - leaving the bonnet open in the pits between runs and leaving the motor off right up to the start seemed to delay the mis-fire.  Happens around 5000rpm and the car stutters badly and won't rev any more - changing up a gear seems to make it go away (until you hit 5k again!)   Problem is only evident in stages, not on the dyno (massive fan blowing into front of engine bay) or on road tests (not WOT for long enough!)

My suspicion is the igniter and/or coil packs are overheating due to higher engine bay temps and generally working these components harder with the Anti-lag.....

My question is this - does the Gp. N ALS setup work the igniter/coils significantly harder than normal?

I would like to build a nice, fat alloy heatsink and mount these bits on it with the fins just poking though the bonnet (which will require lengthening the wiring somewhat - which I've read is not such a great idea....)

I've experienced a similar problem with a customer car where the igniter was not bolted to any heat-sink and was cured temporarily with an empty V can!!

Thanks.

[ashesman]

Anti-lag doesn't really work the igniter or coils any harder.  The two things which work an igniter are engine bay heat (increased by anti-lag) and long dwell time.  I don't think you should have to go as extreme as putting a heat sink through the bonnet.  You are not the only evo rally car owner running antilag so I can only assume the igniter will do the job while it is hot.  The answer might be more in the fact that it is misfiring.  It may not actually be the heat but the fact that at that combination of conditions the spark energy required increases.  I would not modify anything until you have at least tried a new igniter, coil pack (not likely to be a problem) and HT leads.   Also make sure you are NOT running non-resistive spark plugs.  It is an absolute must that you use suppressed plugs and leads.  Also make sure you don't have an excessive plug gap (about 0.8mm would be a good starting point).  It is also important to make sure dwell is setup correctly.  Too long dwell causes unnecessary heating and too short causes reduced spark energy.  I would definitely not overlook HT leads...