Yet Another Misfire Thread.

[Yeedogga]

Hi all,

Car is an r33 gts-t Series 2. Front mount, 3" exhaust, panel filter, stock boost solenoid and 2-stage boost still in place.

Plugs are NGK coppers, std gap 8,500km old.

Above 4,500RPM (when the second boost stage kicks in) i get a misfire, pop pop pop. Pretty standard, well documented. Worse when it is cold.

Bought some second-hand JJR Coils to test if it was coils (they did not come with the little springs, so i used the original springs from the coils, and it misfired even WORSE. Any positive manifold pressure and it would sound like a machinegun and NO power.

Put the stock coils back in and it is still mifiring but only very slightly.

Questions:

- Could the little springs be causing the JJR ones not to work

- Could the JJR ones be stuffed

- Could it be the fuel pump?

Any other bright ideas, Im a bit stumped.

Cheers

Chris

[R31Nismoid]

Change the plugs. Should be done ever 10,000 anyhow IMO especially if your car has been playing up for a while.

After that - recheck ALL connections. Sounds like by changing coil packs something is worse, therefore likely wiring and connections are causes.

[Dose Pipe Sutututu]

what plugs are you running?

I know their NGKs, but which ones? and which heat range?

around 4500rpm mis firing? sounds like an AFM issue, try unplugging the AFM, the ECU will go into LIMP mode and if it does exactly the same thing you know your AFM is playing up.

[dori34]

standard gap so im assuming you're running 1.1mm gapped plugs. if so try BCRP6E w/ 0.8mm gap.

1.1 is known to cause misfire when running higher then standard boost

[Yeedogga]

Thanks all,

Im running BKR5E-11 at the moment, so I will get some BCPR6E(S) from work tomorrow and give it a shot.

Cheers

Edited July 10, 2009 by Yeedogga

[The Dan]

Thanks all,

Im running BKR5E-11 at the moment, so I will get some BCPR6E(S) from work tomorrow and give it a shot.

Cheers

Why not just gap the BKR5E-11's down to 0.8mm instead of going out and buying a whole new set?

If it's not an ignition problem then it's going to be fuel or timing. If the timing has not been touched, then check to make sure the filter has been done and the pump is working correctly.

If you don't have the tools to check fuel flow or pressure, then take it somewhere that does.

And if you are running stock boost - as stated above - then it is extremely unlikely your problem lies in the ignition system, especially considering you changed the coils out.

[bR33nt]

BKR5EYA

NGK

Get these plugs mate, get all 6! Leave ur valley cover off saves u havin to continously take it off n on and also stops abit of heat. My car had same issue. also tape up ur old coilpacks (the stock ones). Use some black electrical tape, nice n tight just go up n down the rubber with a nice firm neat tape job.

Make sure u put it all back correctly. While ur playin mechanics, get a $7 tin of brake clean n clean ur afk, just spary it then air comp it dry.

Put it all back together, double check then triple check.

Leaving the valley cover off.

Then go for a boost. see how u go.

If not pm me.

PS: Plenty of fingers crossed

Brent

Edited July 10, 2009 by bR33nt

[bubba]

NGK BCP6ES-11, not BCRP (the R is for the resister type).

Also, what is the condition of the plugs on the coil harness?

Edited July 11, 2009 by bubba

[Yeedogga]

I have held off from doing anything to see what would happen and because I haven't had any time.

During the day it no longer misfires at all, it runs clean through to redline. The only difference being that the 'valley' cover is now off. I would be surprised if this had any real effect.

I am yet to try it early in the morning when it is really cold outside (The misfire was much worse in the early morning cold air). Ill try it tomorrow and see how I get on.

What are the chances it was a bad batch of fuel?

Cheers

Chris

[Adriano]

Maybe if you wake up before 11 then the problem will come back, easy fix... sleep in

[daisu]

...around 4500rpm mis firing? sounds like an AFM issue, try unplugging the AFM, the ECU will go into LIMP mode and if it does exactly the same thing you know your AFM is playing up.

Limp mode is limited to 3krpm so won't be able to test the AFM like that. Better off swapping with someone temporarily and see if the problem moves to the other car or not.

Why not just gap the BKR5E-11's down to 0.8mm instead of going out and buying a whole new set?

If they are coppers you might as well just replace them because it's cheap enough and the current ones could be stuffed. If they are iridiums/platinums you aren't supposed to gap them.

While ur playin mechanics, get a $7 tin of brake clean n clean ur afk, just spary it then air comp it dry.

Brake cleaner will leave residue on the AFM element, use electrical contact cleaner instead.

[mad082]

NGK BCP6ES-11, not BCRP (the R is for the resister type).

Also, what is the condition of the plugs on the coil harness?

i ran the resistor type in my 33 and had no issues, same goes for probably hundreds of other poeple on this forum. also NGK recommend using the resistor type plug. you will find that most cars with ecu's will recommend using resistor type plugs as the resistor cuts down electrical noise

also it should be said that the BKR plugs are 2.5mm shorter from the gasket to the top of the terminal than the BCPR plugs, so using the BCPR plugs is going to squash the spring up a bit more giving better contact on the spring

[FAT_3L]

is there another way to test the afm as mine goes into limp mode when warmed up i think. cant boost after 2800ish rpm!!

[fat-lad]

having the same problem with my s1 stagea, had it on a scan tool at work and cant tell me nothing, misses idle to redline, new plugs, taped and siliconed up the coils, need to try another set of coils and a airflow meter, im stumped, i feel your pain man,

[Adriano]

Check the trouble codes

[fat-lad]

regards to my problem, sorry for thread hijacking, mine give me a 55- system normal

[Yeedogga]

Hi all, just an update;

New plugs (BCPR6ES)

Siliconed Std coil packs

Bosch 040 in-tank

Seems to be running well so far; no misfire with a 10psi actuator fitted. Time will tell.

Thanks for all the advice guys!

Chris

[RaZ_TuRbO]

fat lad: have you tried the ignitor module? might be worth a shot.

[fat-lad]

mine doest have the igniter box on the vally cover if thats what you mean, just a big black plug, think mines a series 2 engine its in a s1 stagea