Spark Plug Problem - Help Needed

[Monky]

Hi all,

I'm currently running greddy 8's in my RB26 which are made to JIS (slightly longer plug when compared to ISO). The NGK BCPR8ES are also made to JIS but I can't seem to get them here in the UK. They only do 6's and 7's and I need to colder grade (600bhp 1.5 bar HKS 2860 7's). Does anyone know if they are still made, I've been told they are discontinued.

I've tried BCR8ES & BKR8EIX but both of these give really bad hesitation, my guess as they are shorter ISO. With the Greddy plugs it was completely fine, it started to get a intermitent mild hesitation low down coming on boost so I thought spark plugs could do with a refresh whislt not looking that worn. I swapped plugs for the slightly shorter ones, still grade 8 and it was 10 x worse so I attributed the hesitation to spark plugs?

Car is running spitfire coilpacks. When I drive the powerfc is setting off the cat light when it hesitates even just plodding around slowly, barely on boost. I know the light flashes either if you have maxed injector duty, too much knock or air flow. Knock levels were reading high around 40, I thought powerfc flashed if it was above 50? My car does have agressive cams and makes a bloody lot of noise but am still concerned as to what it could be.

The car also won't idle properly anymore, it used to be around 1100 with very lumpy idle but now it struggles at 800 and tries to stall all the time. I'm going to try the old plugs to see if it makes a difference with the hesitation and will report back.

Thanks,

M

[tyndago]

I don't like the splitfire coil packs personally. I have tried them in a couple cars. The cars always ran better and had less misfires with the splitfire coils in them.Some people like them, or they help as replacing 10 year old parts with newer parts does often work out.

I like new OEM coils, replaced fairly often as they cook in the valley of the engine.

The harness also cooks. They get crispy over time, and need to be replaced also.

One thing to check before you go too far. Check each plug for the contact to the top of the plug. I have had a couple recently that were missing the spring/carbon. They would run ok until they got some load or heat into them.

[Monky]

Hey mate thanks for the fast reply.

I've just tried the old plugs, still just as bad. When I rev the car on idle it hesitates, after 4k it clears kind of but a real mission to get up there due to stutter.

I'm getting lots of knock just from reving on idle, when it hesitates it knocks and the dash light flashes as power fc is detecting knock around 3k. Does this give any clues if its knocking?

I'm thinking dodgy mafs as she now struggles to idle and i'm getting knocking maybe from lean conditions, that's what a dodgy maf did on my scooby, any ideas??

M

Edited June 19, 2009 by Monky

[paulr33]

go see a mechanic something is wrong

suggestions

mangled timing

mangled crank sensor

mangled tune

mangled cas bolts

and so on. it shouldnt known mega aggressively at 3k unless something is seriously wrong

check the basics, check timing, check cam belts, check cas, and then go see a mechanic

[Monky]

Thanks for the info defo going to get it looked at as unsure what else it could be.

I thought though when a MAF/AFM fails it effected idle and would also give lean conditions, this was a common problem on the Scoobies. I did clean my AFM's with carb cleaner and may have gone a bit overboard. Regardless I have Z32 MAF's on the way as the current ones are silconed where they have cracked and fell apart when I took them apart!

Once I have the new Z32's it will need a remap so will get everything checked and leave her to rest for now.

M