Miss Firing Problem! Plz Help

[Kaido_RR]

hey;

Car Info:

S1 R33 Skyline Rb25det 100,000km+

Rb20 Turbo

FMIC

Air-Filter

Exhuast

EBC

Ok so here is my problem, my car was missing when i was turing on boost and running 0.8bar (started to happen about 1-2mins after running the car hard with boost on) with the ebc and running stock boost the car would not misses, i would run it hard all the way to redling and it wont have a problem;

So this weekend i change my plugs as i am running in a drift event this week and i need to be able to run boost.

Now i put normal Copper plugs, and gap them to 0.6; Taking it for a test run the car started to misses in every gear above 4000rpm on stock boost, with 0.8bar the car misses as soon as it hit 0.8bar on the boost gauge.

So i took them out and regap them too 0.8 and it has the same problem as above,

Now i check my old plugs they were gap at around 0.5.

I am majorly confused because before i change the plugs it would only miss under the condtion of 0.8bar of boost now it happens under stock boost.

What else could the problem be and how can i check if it is that, i will be taking the car to the mech 2morrow but i wanna get an idea before then

Thanks Michael

[Sheriff Wan]

Check your coil packs etc.

Also why are u running an RB20 Turbo?? Newho's that my 2 cents.

Do a search thers heaps of ways to fix them.

[Kaido_RR]

thanks Sheriff Wan,

I found thread on fixing coil packs, but i have a feeling that mine isnt coil-pack related as, mine didnt happen before i change the plugs.

ohh yeah running a rb20, cuz i bought the car like that long story really

[ecl]

check the actual spark plug and make sure the heat range is right

coil packs, just tape them up at least.. wont hurt to try

timing

crank angle sensor

[datzlr]

most chances it would be blocked fuel filter or coil packs

[Kaido_RR]

ok

Today i replaced my new spark plugs with my old platium plugs (which had only done 20,000km)

THAT FIX THE PROBLEM!,

IT NO LONGER miss firers on stock boost BUT

when i turn boost to 0.8bar the car MISS firers from only about 4000 to 5000rpm THEN it just stops and goes all the way to redline without a problem.

apart from that 1000rpm the car feels fine, goes hard and doesnt feel like its losing any power (and this is backed up by the figures i see on my blitz power meter)

im SOOO CONFUSED!!!

[paulr33]

the stock ecu has excess airflow protection which you will most certainly hit running 0.80bar boost. try it at about 0.60bar boost and see if you get the same problem. the stock ecu picks up too much airflow via the airflow meter and cuts the timing, which results in flat spots

[Kaido_RR]

cheers paulr33, i was thinking about that today, i will give it a try 2morrow

[GTRUSH]

mate your going to have to upgrade ur ignition system. Split fire coil packs are great for skylines with some boost. a lot of people say that thestandard coil packs can handle a lot of boost. I personaly dont believe that cause as soon as i boosted mine to 10 psi it was missin and back firin constantly. Got the new packs and problem solved. But there not cheap!!!

[Nathan_G1]

My R32's running 1.1bar with a VG30 and didnt missfire ever, still doesnt....and thats with the standard coilpacks, the only time it started was when my spark plugs basically disintegrated, got new platinums the the right heat range and bobs ur uncle she's a goer, still no missfires and can run more boost if need be. (dont want to though) but do as paulr33 suggested....