Spark Plug Problem... Need Help!

[FloRida]

hey there... i got a Skyline R33 with HKS Hi-power exhaust, HKS Pod filter, Apexi Turbo timer, BOV, manual boost controller... i just installed the 6 x NGK BKR7EIX spark plugs today and i seemed to get a weired noise from the engine (as if something is hitting somewhere).... after giving it a nice few revs the noise went away but the whole car is shaking when the engine in running... also the exhaust is making a funky sound (like how the old granny cars sound)... my friend told me one or more of the plugs are not firing correctly... i removed and reinstalled all over again but it seems to have no change... also unplugged and replugged the coil connectors one after the other sequentially to see if all the sparkys functioning properly... they all seem to be responsive... i am extremely confused atm... i cannot think of anything else that may cause this... also checked whether engine oil just to be sure which seems to be fine.... i just wanted to get your expert advice.... can please help me out... i bought the plugs because they were listed here to be compatible out of the box with the RB25DET... also i cannot install the stock one's back as 4 of them broke while removing as they were screwed in extremely tight... please help me out guys... really appreciate it... thanks!

http://www.skylinesaustralia.com/forums/Ng...eri-t68157.html

[Aberax]

Are they IRIWAY7 plugs? As these are a raceplug - So i am told by my tuner from his NGK supplier.

If so take them out and get some a lower heat range plug, the RB25DET engine is suppose to have a 5 in there, a 7 is too cold, so its going to foul and misfire as the plug isn't getting hot enough to burn the carbon build up off. So put in a 5 or a 6, when i did my mods back in October, i bought those plugs...they lasted about 1-1.5months and started to misfire - car sounded like a WRX. I took it back to my tuner and he put in some heat range 6 plugs that have been gaped to 0.8mm - i think. So far the car has been fine, been about 2-3 weeks so far.

EDIT: Either way, 7 is too cold, take them out and put a 5 or 6 in.

[FloRida]

hmmm... strange... btw what is the stock plug gapping (0.8mm)?? maybe thats the reason.... anyway thanks for the tip....

[mosquitocoils]

Yeah I use the 6 range plugs. You may not need to gap down to 0.8mm either if your coilpacks etc are working well. I've been told to stay around 1-1.1 unless you have issues.

[Aberax]

The ones you have now would be at about 1-1.1, which is fine. However if your coils aren't in too good condition maybe get the gaped down, or buy them pre-gaped - i think my tuner said mine are heat range 6, pre-gaped to 0.8 and running on new Superspark coils.

[FloRida]

hey thanks for the insight guys... i finally got it fixed myself today... the 1st plug (one used for the idling) was not firing... i put one of my old plug back in there and all seems way better now... 1 stock plug and 5 BKR7EIX... just in case the plugs fail in near future, which other brand is good apart from NGK for R33 GTST S1??

[mad082]

just use NGK BCPR6ES plugs (if you want the 1.1mm gap plugs just add 11 onto the end of the part number). they are a heat range 6 plug, but a copper not an iridium so they only cost about $6 each and just change them every 10 to 15,000kms. works out cheaper in the long run than using iridiums in my experience.

[bozodos]

Thinking about trying 1.1 mil gapped plugs next time in mine since I am changing them due to carbon fouling every ~10k.

[mosquitocoils]

hey thanks for the insight guys... i finally got it fixed myself today... the 1st plug (one used for the idling) was not firing... i put one of my old plug back in there and all seems way better now... 1 stock plug and 5 BKR7EIX... just in case the plugs fail in near future, which other brand is good apart from NGK for R33 GTST S1??

I highly doubt it's a 'stock' plug.... it would be around 15 years old by now!

You might as well slap a whole set of the same ones in. I would, just so I know they're all fresh and new at the same time.

Also what gap did you end up using?