Jump to content
SAU Community

New Spark Plugs= Missfire

camoo

By camoo,
in General Maintenance

 Share

Recommended Posts

camoo Collaborator

camoo

Posted
Posted

I have a 98 r34 gtt, 3"turbo back, FMIC, boost controller running 12psi.

while doing the 100k service, i took out its denso iridium IK20 plugs with a gap of 1.1

and replaced them with NGK bcpr6es gapped to .8

Now it misses at idle and a little when accelerating lightly up to 2000rmp, but is fine when driving normally and when hammering it.

I played around with the gapping and the smaller ther gap the worse it is, but even at 1.2, the miss at idle remains.

Its not running lean, ive checked coils, airflow meter and for any vacuum leaks, all that aside,

the miss dissapears when i put the iridiums back in....

Im stumped, my mechanic is stumped...

I know i could just run the iridiums, but there must be something causing this, and its driving me nuts....

Could it be injectors?

Any help please??

Link to comment
https://www.sau.com.au/forums/topic/361819-new-spark-plugs-missfire/
Share on other sites
mad082 Grand Master

mad082

Posted
Posted

put the old plugs back in. if the miss goes away then you no it's am issue with the plugs. if the issue stays then i think you will find that the issue is with the coils. may have been a bit dodgy before hand and in the process of changing the plugs the got damaged and now they are worse.

camoo Collaborator

camoo

Posted
  • Author
Posted

Sounds like my issue i have just changed my injectors..

Sounds like its on 5 cylinders if you gently rev it..

yes thats what mine sounds like, did the injectors help?

just buy the stock plugs n gap them too .7 or.8, cheap as fu*k and will probs fix your problem n near last as long as iridium plugs- i think they are

BCPR6ES-11

tried that, didnt help

put the old plugs back in. if the miss goes away then you no it's am issue with the plugs. if the issue stays then i think you will find that the issue is with the coils. may have been a bit dodgy before hand and in the process of changing the plugs the got damaged and now they are worse.

tried that, different only iridiums make it go away, also swapped my coils witha new set to test, made no difference

Maybe you dislodged some crud and it dropped into one cylinder?

blew it all out with compressor before i removed plugs, and it goes away with iridium plugs

thanks though eveyone.... :s

camoo Collaborator

camoo

Posted
  • Author
Posted (edited)

Is ur ecu tunable? Some skylines do this. Its like an intermittant lean pop at idle?

If it annoys u just richen up the idle a tiny bit or keep running the iridiums if thats what ur car likes.

as far as i am aware its still the standard ecu as it has the sticker/seal on it.

im the first oz owner too, i think they have to make sure the ecu is standard when going through compliance... unfortunately lol

and yes it sounds like a lean pop, but my tuner put it on the dyno and its still rich, runs safe allthrough the rev range with a smooth power curve.

:(

im ok with running iridiums... but still i really wanna know why its doing this.. is this common at all?

Edited by camoo
camoo Collaborator

camoo

Posted
  • Author
Posted

Alot of skylines have lean pop at idle intermittantly.

I normally richen the idle until the popping stops.

Why it happens with certain plugs i honestly cant answer that.

hmmm driving through the city today i can notice it while going slow.... very annoying....

and its already running rich...

ill put iridiums back in and see how it runs...

any more ideas though?

The.Godfather Enthusiast

The.Godfather

Posted
Posted

did you drop one of the plugs when fitting them? they are fragile things and can get damaged easily...

but yeah throw your old ones in, even if its one by one and see if the missfire at idle goes away.

camoo Collaborator

camoo

Posted
  • Author
Posted

did you drop one of the plugs when fitting them? they are fragile things and can get damaged easily...

but yeah throw your old ones in, even if its one by one and see if the missfire at idle goes away.

na didnt drop any,and even then, i went and bout another set of the NGKs just to be sure.

Also tired replacing plugs 1 at a time, and untill its all iridium, it still misses....

cheers though..

camoo Collaborator

camoo

Posted
  • Author
Posted

so im going to try the o2 sensor in the exhaust....

Not to sure if this will have to much of an affect but with my limited knowlede i believe this is a logical step...

Any one agree or not?

help???? lol

camoo Collaborator

camoo

Posted
  • Author
Posted

NOTHING TO DO WITH THE O2 SENSOR!!!!!!

Standard Iridium plug is a (NGK) heat range 5, I believe. Try some BCPR5ES plugs, see what happens.

yeh is did nothing tring another o2 sensor, so good call...

i got some ngk iridiums to put in tomorrow, just annoying that everine else with this same angine and same mods can run standard copper plugs, yet mine wont...

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Jarsky
      R33 Fuel Pump & Brakes after alarm swap

      By Jarsky · Posted

      Thought I would get some advice from others on this situation.    Relevant info: R33 GTS25t Link G4x ECU Walbro 255LPH w/ OEM FP Relay (No relay mod) Scenario: I accidentally messed up my old AVS S5 (rev.1) at the start of the year and the cars been immobilised. Also the siren BBU has completely failed; so I decided to upgrade it.  I got a newer AVS S5 (rev.2?) installed on Friday. The guy removed the old one and its immobilisers. Tried to start it; the car cranks but doesnt start.  The new one was installed and all the alarm functions seem to be working as they should; still wouldn't start Went to bed; got up on Friday morning and decided to have a look into the no start problem. Found the car completely dead.  Charged the battery; plugged it back in and found the brake lights were stuck on.  Unplugging the brake pedal switch the lights turn off. Plug it back in and theyre stuck on again. I tested the switch (continuity test and resistance); all looks good (0-1kohm).  On talking to AVS; found its because of the rubber stopper on the brake pedal; sure enough the middle of it is missing so have ordered a new one. One of those wear items; which was confusing what was going on However when I try unplugging the STOP Light fuses (under the dash and under the hood) the brake light still stays on. Should those fuses not cut the brake light circuit?  I then checked the ECU; FP Speed Error.  Testing the pump again; I can hear the relay clicking every time I switch it to ON. I unplugged the pump and put the multimeter across the plug. No continuity; im seeing 0.6V (ECU signal?) and when it switches the relay I think its like 20mA or 200mA). Not seeing 12.4V / 7-9A. As far as I know; the Fuel Pump was wired through one of the immobiliser relays on the old alarm.  He pulled some thick gauged harness out with the old alarm wiring; which looks to me like it was to bridge connections into the immobilisers? Before it got immobilised it was running just fine.  Im at a loss to why the FP is getting no voltage; I thought maybe the FP was faulty (even though I havent even done 50km on the new pump) but no voltage at the harness plug.  Questions: Could it be he didnt reconnect the fuel pump when testing it after the old alarm removal (before installing the new alarm)?  Is this a case of bridging to the brake lights instead of the fuel pump circuit? It's a bit beyond me as I dont do a lot with electrical; so have tried my best to diagnose what I think seems to make sense.  Seeking advice if theres for sure an issue with the alarm install to get him back here; or if I do infact, need an auto electrician to diagnose it. 
    • Duncan
      After market rear camber arm adjustment

      By Duncan · Posted

      Then, shorten them by 1cm, drop the car back down and have a visual look (or even better, use a spirit level across the wheel to see if you have less camber than before. You still want something like 1.5 for road use. Alternatively, if you have adjustable rear ride height (I assume you do if you have extreme camber wear), raise the suspension back to standard height until you can get it all aligned properly. Finally, keep in mind that wear on the inside of the tyre can be for incorrect toe, not just camber
    • V35Newbie
      After market rear camber arm adjustment

      By V35Newbie · Posted

      I know I have to get a wheel alignment but until then I just need to bring the rear tyres in a bit they're wearing to the belt on the inside and brand new on the outside edge. I did shorten the arms a bit but got it wrong now after a few klms the Slip and VDC lights come on. I'd just like to get it to a point where I can drive for another week or two before getting an alignment. I've had to pay a lot of other stuff recently so doing it myself is my only option 
    • Duncan
      After market rear camber arm adjustment

      By Duncan · Posted

      You just need a wheel alignment after, so just set them to the same as current and drive to the shop. As there are 2 upper links it may also be worth adding adjustable upper front links at the same time; these reduce bump steer when you move the camber (note that setting those correctly takes a lot longer as you have to recheck the camber at each length of the toe arm, through a range of movement, so you could just ignore that unless the handling becomes unpredictable)
    • V35Newbie
      After market rear camber arm adjustment

      By V35Newbie · Posted

      I got adjustable after market rear camber arm to replace the stock one's because got sick of having to buy new rear tyres every few months. Can anyone please let me know what the best adjustment length would be. I don't have the old ones anymore to get measurements. I'm guessing the stock measurement minus a few mm would do it. Please any help on replacing them would be fantastic I've watched the YouTube clips but no-one talks about how long to set the camber arm to.
×
×
  • Create New...