Alright I did my dyno tune on Saturday at 25 psi w/ meth/water, it would miss fire badly at the high rpm range. I'm thinking it could be my iridium spark plugs so, I'll try to change it out to some copper plugs. Anyway, anyone else have any idea what it could be.


It actually put down 375hp and 335tq was at 24psi with meth/water. The a/f was around 11.7 to 12.0

 

I would try some copper plugs gapped tightly - that should do it

Also if you have a lot of miles - then replace the two stock ignition plug wires they go bad after time

Finally a HKS twin fire helps a lot

AL

 

+1 on that. Wires are super cheap to replace. Also check the ignition coils for any bulging or deformities.

 

I already have the HKS DLI w/ denso iridium plugs, but I do have to stock plug wires............the spark plugs are probably 3 month old. Suxs, I really want to turn the boost up and put down some good numbers.

My Evo only just broke 10k miles..........do you think the wire would go bad that early?

 

I would do the copper plugs gapped correctly then try the wires. I think they are less than 20 dollars so it doesn't hurt to try. Copper plugs are around 2-3$ each.

If that doesnt work u may want to unhook the DLI just to see if that could be causing a problem.

The wires generally don't go bad in 10k miles but if they've been bent or tugged in they could.

 

mine does the same thing and i am running denso iridium 1 step colder.. stock ignition with 20k on it. Did try my friends sun auto amp helped a little but still braks up badly up top.

 

ME 2! kinda. I don't feel or hear the engine missing in any gear up to 140 mph but , my engine light come on and the code said it was a misfire. So yeah how do you fix this???

-Matt

 

I put denso's in and had a misfire with brand new plugs... this is why you should try copper NGK's.

Apex1: you probably have another issue. P0300 probably.

 

whats PO 300??

 

In your case I would then say you just need a tigher spark plug gap

Al

 

Thats what I was told. Get a tighter gap?

 

Yeah im in the same boat. I think im gonna try some NGK's cause i dont like these densos. We had to re-gap the plugs on the dyno and if was ok for a while but i think i just fouled them out on the way home.

 

Kewl........I'll try it out for sure.

Any suggestion to what gap I should try?

 

If Milo's Evo is a IX, which I'm guessing it is since its an MR SE, then no one makes copper plugs for the Evo IX yet. I've seen a lot of people blow out spark at higher boost, and it seems like gapping to 0.22 works pretty good. Thats what I'm going to try before I start tuning for my HSF-5 kit.

 

be real careful - the iridium tip is fragile