Which Spark plugs?

[Sparky84]

Hi All

Having a slight spark problem at present I think, plugs are always black
I've been using NGK DPR8EA-9 but specs say DP8EA-9 if you're not in Sth Africa, so are the resistor plugs correct or should I be using non resistor ones?

Cheers Alan

[oldktmdude]

   G'day Alan, I've been using NGK DPR8EA-9's since I've had my FJ without any issues. Plug colour is usually a little on the dark side but I have never had a plug fail. Are you having an issue with plugs fouling?
   Regards, Pete.

[Sparky84]

   G'day Alan, I've been using NGK DPR8EA-9's since I've had my FJ without any issues. Plug colour is usually a little on the dark side but I have never had a plug fail. Are you having an issue with plugs fouling?
   Regards, Pete.

Hi Pete

I too have always used those only because stores only stocked those.
The #4 plug mainly, it actually could that much it would fire, took off cap bike ran the same.

Still looking into problem found on Dyno in Nowra that found issue with picking up revs on #4 lead.

Changed cap, now looking into voltage to coils and "coil mod with relay"

Cheers Alan

[Sparky84]

   G'day Alan, I've been using NGK DPR8EA-9's since I've had my FJ without any issues. Plug colour is usually a little on the dark side but I have never had a plug fail. Are you having an issue with plugs fouling?
   Regards, Pete.

Hi Pete

I too have always used those only because stores only stocked those.
The #4 plug mainly, it actually could that much it would fire, took off cap bike ran the same.

Still looking into problem found on Dyno in Nowra that found issue with picking up revs on #4 lead.

Changed cap, now looking into voltage to coils and "coil mod with relay"

Cheers Alan

Sorry Pete,

Spell check suxs ! Meant to read,

"The #4 plug mainly, it actually fouled that much it wouldn't fire"

[a.graham52]

Question u have.... is 4 misfiring because it's fouled or fouled because it's missing?

Are you positive number 4 carb is not over fueling?

If it is indeed ignition related, swapping coils and plug wired around will potentially show you the fault because the misfire will move to another cylinder

[Sparky84]

Question u have.... is 4 misfiring because it's fouled or fouled because it's missing?

Are you positive number 4 carb is not over fueling?

If it is indeed ignition related, swapping coils and plug wired around will potentially show you the fault because the misfire will move to another cylinder

"Fouled because it's missing" I believe, as when dyno was being done they had trouble picking rpm from #4 lead, very intermittent.

I started it the other day for a ride and it didn't sound right, found #4 header dead cold (I was holding it with my hand, tight) after slight warm up and all other headers I could touch due to very hot. Changed that plug all OK?

I'm not sure if #4 carb is over fueling, tracing electrical first.

Cheers Alan

[Sparky84]

Found voltage at both coils plugs to be OK, 12.35v, so I didn't do coil mod.
Original caps ranged from 9.10 - 10.89k ohms, but also found 2 caps had loose cap screws, 1 seemed not to be screwed firmly onto lead(it was one with a loose cap screw)
Also small spring in cap was discoloured, I don't think it was corrosion as I believe it to be stainless.
Spark plugs ranged from 4.45 - 4.81k ohms
New caps ranged from 8.68 - 9.41k ohms

Cut back leads about 15mm and fitted new caps.
Cleaned plugs up and set gap to 0.85 (I swapped #4 for another after checking spark was not good)

Just need to take it for a run now

but do I use non resistor plugs resistor DP8 or DPR8

Cheers
Alan

[racerrad8]

Alan,

I only use & sell NGK resisted spark plugs for the past twenty years of my FJ experience.

I have the standard plug and Iridium in both stock and one step colder heat range. Search NGK at the website and you can see the plug options.

Did you resistance check the coils on the primary & secondary sides?

99% of the time a black spark plug is a carb issue.

Randy - RPM