Miss at high revs?!

[r33GTS-t-200kw]

Hi all

This afternoon I went to the trouble of cleaning my iridiums and regapping them as the car has a slight miss above 4k revs on high boost. I thought re-gapping the plugs to .8m may make it go away. On low boost the car has HEAPS more grunt, but when you switch it to high boost it is actually worse. Very bad miss mainly around 5-7k. What is the reccommended gap to stop the missing? Its either plug gap or coils, but I dont think its the coils as the missing got worse :headspin: after the re-gap.

Any thoughts or suggestions/reccommendations?

Cheers

[benm]

Suggestion: Get new coils.

[krzysiu]

.9 or 1 is the way to go.

[WHITER33GTS-T]

My car has done the same thing. Better buy some splitfire coils.

[enilyks33r]

I found that .65-.70 works a treat after finding .80 was breaking down under higher boost levels, it now does not miss and economy etc is uneffected.

If this doesn't fix the problem, it is the coils and/or excessive fueling.

[Abo Bob]

I would have thought you would lose power if you gapped them that low.

[GIGOLO]

How much boost are you running? What engine and mods?

I have Iridiums gapped at .8 and have never had any misses throughout the rev range on my RB25. I bought my plugs pregapped at .8 and they havn't moved in 12 months or gotten excessively dirty even after running a 10% toluene mix.

You may have damaged the Iridium tips when you cleaned or gapped them?

Try a new set of copper plugs gapped at .8, its alot cheaper that getting new coils.

[benm]

re-gapping them down is just a quickfix for fcuked coils.

[Munna]

Mine are gapped at 0.8 and I dont have any probs but I also have an SAFC.

1. It Could be a faulty or dirty coil or coils.

2. The ECU might be seeing to much airflow for its liking and over fueling a quick fix for that the SAFC.

[r33GTS-t-200kw]

going to try .7 too see if it works. tried 1.1 which is the factory setting on the iridiums in the NGK book at work. That really sucked ass. Will let you know how the .7's go. I will also be trying some of the old plugs that i have to see if its a ****ed plug.

[Robo's]

By making the gap smaller you are just hiding that fact your ignition system cannot ignite the larger gap of spark. Bigger spark means bigger power. I had to gap my down to .65 with the stock ignition system (obviously they where faulty) but now with spitfires, ive increased my gap to .9. Also the stock ECU maybe dumping too much fuel in for the plugs to fire, hence the miss. Check it out on a dyno for A/F ratios

[mabru]

I'm wary of gapping iridiums, I thought it was really easy to destroy them by doing so. I would love to gap mine down but at the price I paid for them I really don't want to ruin them.

-Matt