Jump to content
SAU Community

Recommended Posts

Ok here is the story & YES i have read all the threads i could find on topic

I have a 97 s2 Gts-T

Mods are:

8.5psi (Turbotech)

R34SMIC

Pod

EVERYTHING else including exhaust is std

When i got car always had a slight pop on idle but never missed through rev range....anyway as i had changed g/box & diff oils, all filters etc since i go car i though id change the plugs as god knows how long they had been in there...got a set of iridiums heat range 6 (originals were 5) & threw them in...straight away it started to hesitate/miss at 4500-5000rpm so i did some research on here & regapped to 0.8mm & it made a hug difference but miss was still there on idle & in cold it would hesitate occasionally but i lived with it...then it started getting worse so i thought time for splitfires

whacked them in & presto miss gone on idle & no hestitation...but first time i drove it in colder weather at night its back???

Then I noticed when i give it a good kaning it tends to go away (as it does in the warmer weather) so im starting to think maybe going from a heat range 6 plug from 5 might be the whole problem as it seems when its cold they do not fire properly but when its warmer or after i drive it hard it seems to be fine

Maybe i should go back to a heat range 5 & my car is not modded enough to benefit from a heat range 6 plug & infact running worse

Any thoughts as im stumped?

Link to comment
https://www.sau.com.au/forums/topic/180944-misfireplugscoilpacks/
Share on other sites

you have said that they are 0.8mm gap but how old are the plugs? and what sort are they?

you shouldn't have to run the smaller gap with splitfires.

i would also suggest not running too much boost with the stock exhaust. it is a bit restrictive and will keep more heat in the turbo.

the reason why it goes away if you fang it is that the plugs are fouling. your o2 sensor may be a bit stuffed and causing you to run rich at low load which is fouling the plugs. then when you fang it the plugs are cleaning themselves.

you have said that they are 0.8mm gap but how old are the plugs? and what sort are they?

NGK Iridiums & they are only 3months old

you shouldn't have to run the smaller gap with splitfires.

thats what i though hence why i am stumped

i would also suggest not running too much boost with the stock exhaust. it is a bit restrictive and will keep more heat in the turbo.

yea thats why im at 8.5psi & not 10-12psi

the reason why it goes away if you fang it is that the plugs are fouling. your o2 sensor may be a bit stuffed and causing you to run rich at low load which is fouling the plugs. then when you fang it the plugs are cleaning themselves.

but i get my usual km out of a tank? if o2 sensor was stuffed wouldn't that affect my kms per tank?

not if it was stuffed when you got the car. the hotter plugs you were running got to their self clean temp easier so they could burn the extra fuel easier.

and how many kms old are the plugs? not age sorry.

pull them out and have a look and have a look and see if they are fouled up (all black and sooty). if they are then it is running rich and it would be worth testing your o2 sensor.

not if it was stuffed when you got the car. the hotter plugs you were running got to their self clean temp easier so they could burn the extra fuel easier.

and how many kms old are the plugs? not age sorry.

pull them out and have a look and have a look and see if they are fouled up (all black and sooty). if they are then it is running rich and it would be worth testing your o2 sensor.

ahh i see & does make sense

plugs done about 2000-3000k max

I heard o2 sensor should be changed at 60,000 anyhow? that true? if so im due for one as i just have passed 70,000

regardless i should change plugs yea?

THANKS

try changing the plugs to a set of copper ones (bcpr6es) and see if that makes a difference (they are only about $4 a plug, so won't break the bank). it also depends on if the o2 sensor was even changed when it was supposed to.

try disconnecting it and see if alters your fuel economy.

try changing the plugs to a set of copper ones (bcpr6es) and see if that makes a difference (they are only about $4 a plug, so won't break the bank). it also depends on if the o2 sensor was even changed when it was supposed to.

try disconnecting it and see if alters your fuel economy.

cheers

what gap? the std 1.05mm or gap down to 0.8mm?

Ok i think i may have gotten wrong iridiums originally & when i re-gapped i think i might have damaged the tips so i have a new set on the way which are already 0.8mm & i also have a new NTK o2 sensor on the way as it prob has never been changed (Thanks Kudos Motorsport) so will throw in new sensor & plugs when i receive & hopefully problem is solved....

if not i wont know what the hell it as i would have changed coilpacks, plugs, o2 sensor & would only really leave AFM or CAS in the equation

  • 1 month later...

I was talking to a mechanic the other day, and he said you are better with "Normal" plugs.

We were discussing a similar problem with my drive at the time.

His opinion was that the Platinum ones, once they get a kicking, dont seem to recover, and need changing again... !!!

Makes me wonder why I am using them. at the price they are?!?

Now I am confused?!?!...., I thought they were the dogs goodies, but now...

Anyone else know better, and can substanciate it?, 'cos I'd love to know which way to go.!

BTW, the flat spot on mine is at 5500 RPM. @14, 18 & 22 PSI (not using any more than 14PSI at the moment BTW!)... Kinda wrecked the 24PSI attempt for me that day!!

Mr Dyno said it was the coils, but I noticed a noisy Fuel Pump on Sunday eve, and someone said if it had been run dry, then it could have been damaged(it's about 250Km old now).

My thoughts are, if it was noisy, and a wavering noise was coming from it, there could be a problem, but the Dyno never picked up a lean situation, or any fuelling problem.

I am going to try the ones that Just Jap sell... the ones with 10% extra voltage. Seem a better price, and offer more spark too, I'll update when done.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • A few small updates since the previous post and lessons. I decided to do a little interior light upgrade on the 110. I quite like the iilumo items, even if they're a bit of a premium over other brands. You'll also note the Stedi Fogs, that will go into the S15 fog lights as I needed to match the bulbs since I got the new ones earlier. I hope they fit as the body is quite a bit longer than your normal bulb.  Annoyingly, I managed to trip the fuse, which normally wouldn't be an issue until I located the fuse. I can't say I've ever come across this. I had lucked out that someone nearby had a spare, but oddly enough Toyota dealerships seem to keep this in stock. I ordered some to keep in my stash and as luck would have it, someone else nearby tripped the same fuse so I passed on the favour.  I also did a little service on the 110 ahead of some additional work coming up. It's been annoying that Goleby's stopped carrying this particular HKS filter for the 110, so now I need to keep them on order from Japan. I also took the opportunity to install a bash plate and number plate riser. The plate riser is such a cheap but nice fix to help really tidy up the car. I'm tempted to now also replace my headlights, on this car. Both items were from Project Aero.    I also needed to replace the rear tyres on the 110, and after trying to get it aligned learnt that I need to replace some bushes in the front end, so that's next.  Closing out this update with a nicer picture as always! 
    • Yeah mate, never miss it.
    • Any going to watch World Time Attack at SMSP this year?
    • Appreciate the correction on the "ground", that will make a huge difference to looking at this. That makes complete sense about AF70/AF71 which is what I had come down to being the issue, one of these. I'll have another look in the ignition wiring when I get a chance next week. I'll also make up a jumper wire for running that AF73 test.  ECU is fine, relay itself is fine, pump harness is fine and the pump itself is fine. I am going to upgrade the Walbro 255 anyway with a DW300 I have since I need to replace the fuel sender and I'm going to upgrade the FPR with my chasebays kit ready for new plenum/injectors/dbw, but I'll get this working first. That's why this is so frustrating. 
×
×
  • Create New...