Jump to content
SAU Community

Fouled Spark Plug Questions

gtr judd

By gtr judd,
in Australian Capital Territory

 Share

Recommended Posts

gtr judd Proficient

gtr judd

Posted
Posted (edited)

Hey guys I have a question or more of a second opinion.

I bought my GTR up recently (hasn't been driven in 14months) and it has a misfire throughout the rev range, cold or warm.

I babied it home where it has been sitting waiting for some attention.

Now I know it could be a number of things but today I pulled the coil packs and plugs for a little look.

I found the coil packs seemed to be in good condition, the rubber boots are perfect, however the coil pack loom is hard and crunchy, some of the clips were brittle and breaking - so I Imagine fairly buggered.

Now the plugs....so the middle two plugs have me a little worried, they where pretty dirty, a little wet looking and smelt pretty heavily of petrol. The other 4 seemed the normal light brownish colour, dry and decent condition.

So Im thinking a few things, MAF or coil pack loom causing it to run rich....it would also explain the dirty rear bumper.

Has anyone got any opinions? I'm fairly new to RBs.

Edited by gtr judd
Link to comment
https://www.sau.com.au/forums/topic/433525-fouled-spark-plug-questions/
Share on other sites
gtr judd Proficient

gtr judd

Posted
  • Author
Posted (edited)

Yea my plan was to drop all fluids and a major service as I'm not sure of the service history. I cleaned and gapped the plugs to .8

As for the injector, it doesn't smell like fuel on idle or while driving. How is the best way to check?

I know it had a leaky injector 6 years ago lol. But I'm not sure if the one injector was fixed or new o rings throughout

Edited by gtr judd
Sinista32 Grand Master

Sinista32

Posted
Posted (edited)

I think your on track. Give it a good service.

and

Clean AFM's

Drop your fuel out and start a fresh. Replace fuel filter

$30 for 6 new NGK BCP7RES plugs.

Grab a new injector loom to by the sounds of things to.

Ps. if your concerned about the injectors I have some Denso 720's

Edited by Sinista32
gtr judd Proficient

gtr judd

Posted
  • Author
Posted (edited)

I think your on track. Give it a good service.

and

Clean AFM's

Drop your fuel out and start a fresh. Replace fuel filter

$30 for 6 new NGK BCP7RES plugs.

Grab a new injector loom to by the sounds of things to.

Ps. if your concerned about the injectors I have some Denso 720's

I will clean the AFMs today, I have a can of cleaner floating about. The tank is nearly empty, so getting rid of the stale fuel shouldn't be hard :)

Are copper spark plugs a better option over iridium's or similar? How much more regularly do they need to be changed?

Are the eBay looms OK or should I get one from a site sponsor, I have been lookin at Kudos?

720s would be a nice step up but then it needs a tune etc, I'll wait till its all running nice before I start upgrading lol. I might take mine out and get them cleaned and checked.

Chuck some O2 sensor and temp sensor action in there too.

These could also cause richness if they're stuffed.

Yea good idea,I'll ave a look at them too

Thanks for your help guys.

Edited by gtr judd
Sinista32 Grand Master

Sinista32

Posted
Posted (edited)

Irridiums on a stock GTR are fine and last 2-3 yrs - Cost $150

Copper on a worked GTR up to a year - Cost $30

Edit: cant comment on E-bay looms - never bought one.

Shouldn't be to exy for OEM off one of our traders.

Kudos is the cheapest you will find.

Edited by Sinista32
gtr judd Proficient

gtr judd

Posted
  • Author
Posted (edited)

Irridiums on a stock GTR are fine and last 2-3 yrs - Cost $150

Copper on a worked GTR up to a year - Cost $30

Edit: cant comment on E-bay looms - never bought one.

Shouldn't be to exy for OEM off one of our traders.

Kudos is the cheapest you will find.

My Gtr is stock motor wise besides a cat back exhaust, so I might just go the coppers for the moment.

Sweet I'll get in to contact with them and see what I can do.

Edited by gtr judd
gtr judd Proficient

gtr judd

Posted
  • Author
Posted

After I cleaned the plugs the other day and re installed them I never started the car, a couple days later I went to and flat battery. I have been swamped with work and one of my boys birthday party's (20x5 year olds :/) as well as football but today I started it

...........

Its alive again, no misfire, ran 1000x better.

Yay can't wait to get it all serviced and running 100%

  • 3 weeks later...
gtr judd Proficient

gtr judd

Posted
  • Author
Posted

Oh are they? Thats is on my to do list.

My misfire comes back intermittently but then drives ok, so I'll replace the plugs shortly and see, the loom definitely needs looking at, being all crunchy etc

RosieR34 Grand Master

RosieR34

Posted
Posted

From about 3600+ it would misfire and would cut the engine off at 5000. Changed sparkies and coilpacks - from memory. Rob may have a better memory as it happened in the first week of purchasing the R33 to which I first entered the scene.

gtr judd Proficient

gtr judd

Posted
  • Author
Posted

Ahh ok, mine has a slight missfire on idle and as soon as you give it any throttle its coughs and farts

I really dont have the money to be throwing parts at it to fix it yet, but once my other car sells and my wedding is 100% paid I will be much happier too

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

    • sinn3r
      R34 Skyline climate control unit transistor

      By sinn3r · Posted

      perhaps i should have mentioned, I plugged the unit in before i handed over to the electronics repair shop to see what damaged had been caused and the unit worked (ac controls, rear demister etc) bar the lights behind the lcd. i would assume that the diode was only to control lighting and didnt harm anything else i got the unit back from the electronics repair shop and all is well (to a point). The lights are back on and ac controls are working. im still paranoid as i beleive the repairer just put in any zener diode he could find and admitted asking chatgpt if its compatible   i do however have another issue... sometimes when i turn the ignition on, the climate control unit now goes through a diagnostics procedure which normally occurs when you disconnect and reconnect but this may be due to the below   to top everything off, and feel free to shoot me as im just about to do it myself anyway, while i was checking the newly repaired board by plugging in the climate control unit bare without the housing, i believe i may have shorted it on the headunit surround. Climate control unit still works but now the keyless entry doesnt work along with the dome light not turning on when you open the door. to add to this tricky situation, when you start the car and remove the key ( i have a turbo timer so car remains on) the keyless entry works. the dome light also works when you switch to the on position. fuses were checked and all ok ive deduced that the short somehow has messed with the smart entry control module as that is what controls the keyless entry and dome light on door opening   you guys wouldnt happen to have any experience with that topic lmao... im only laughing as its all i can do right now my self diagnosed adhd always gets me in a situation as i have no patience and want to get everything done in shortest amount of time as possible often ignoring crucial steps such as disconnecting battery when stuffing around with electronics or even placing a simple rag over the metallic headunit surround when placing a live pcb board on top of it   FML
    • dbm7
      R34 Skyline climate control unit transistor

      By dbm7 · Posted

      Bit of a pity we don't have good images of the back/front of the PCB ~ that said, I found a YT vid of a teardown to replace dicky clock switches, and got enough of a glimpse to realize this PCB is the front-end to a connected to what I'll call PCBA, and as such this is all digital on this PCB..ergo, battery voltage probably doesn't make an appearance here ; that is, I'd expect them to do something on PCBA wrt power conditioning for the adjustment/display/switch PCB.... ....given what's transpired..ie; some permutation of 12vdc on a 5vdc with or without correct polarity...would explain why the zener said "no" and exploded. The transistor Q5 (M33) is likely to be a digital switching transistor...that is, package has builtin bias resistors to ensure it saturates as soon as base threshold voltage is reached (minimal rise/fall time)....and wrt the question 'what else could've fried?' ....well, I know there's an MCU on this board (display, I/O at a guess), and you hope they isolated it from this scenario...I got my crayons out, it looks a bit like this...   ...not a lot to see, or rather, everything you'd like to see disappears down a via to the other side...base drive for the transistor comes from somewhere else, what this transistor is switching is somewhere else...but the zener circuit is exclusive to all this ~ it's providing a set voltage (current limited by the 1K3 resistor R19)...and disappears somewhere else down the via I marked V out ; if the errant voltage 'jumped' the diode in the millisecond before it exploded, whatever that V out via feeds may have seen a spike... ....I'll just imagine that Q5 was switched off at the time, thus no damage should've been done....but whatever that zener feeds has to be checked... HTH
    • 25RBGT
      Got this r31 silhouette flood car to rebuild.

      By 25RBGT · Posted

      First time we have seen lights 
    • Wazmond
      WGNC34 - floor mats

      By Wazmond · Posted

      I think Fitmit had some, have a look on there (theyre Australian as well)
    • soviet_merlin
      Howdy Y'all

      By soviet_merlin · Posted

      Hah, fair enough! But if you learn with this one you can drive any other OEM manual. No modern luxury features like auto rev-matching or hillstart assist to give you a false sense of confidence. And a heavy car with not that much torque so it stalls easily. 
×
×
  • Create New...