Hi everyone,i have a civic with a d15z4 engine with light mods and i am wondering why the iridium spark plugs do not burn grey? what might cause it to burn brown?

Post a pic post a pic!!!

Light brown\tan is ok...thats normal. Blackened electrodes are also normal. If dark brown then im assumming your adding random goodies in your tank. Dont...its bs..its safer to run higher octane then actually use an octane booster.......if you are, run the rest of it through as in..use the rest of the gas in your tank, then fill her up. Seaform ur engine (hopefully you can purchase some where you live...yes i noticed ur License plate)...through vacuum line then change ur spark pluggies after.

This is only a suggestion...would be the most logical thing i'd do if i were in your shoes. You dont have to really seafoam...but i'd recommend. =)

Check out this article
http://www.classictruckshop.com/clubs/e ... /plugs.htm


Normal
APPEARANCE: This plug is typical of one operating normally. The insulator nose varies from a light tan to grayish color with slight electrode wear. The presence of slight deposits is normal on used plugs and will have no adverse effect on engine performance. The spark plug heat range is correct for the engine and the engine is running normally.

CAUSE: Properly running engine.

RECOMMENDATION: Before reinstating this plug, the electrodes should be cleaned and filed square. Set the gap to specifications. If the plug has been in service for more than 10-12,000 miles, the entire set should probably be replaced with a fresh set of the same heat range.

Oil Deposits


APPEARANCE: The firing end of the plug is covered with a wet, oily coating.

CAUSE: The problem is poor oil control. On high mileage engines, oil is leaking past the rings or valve guides into the combustion chamber. A common cause is also a plugged PCV valve, and a ruptured fuel pump diaphragm can also cause this condition. Oil fouled plugs such as these are often found in new or recently overhauled engines, before normal oil control is achieved, and can be cleaned and reinstalled.

RECOMMENDATION: A hotter spark plug may temporarily relieve the problem, but the engine Is probably in need of work.

Incorrect Heat Range


APPEARANCE: The effects of high temperature on a spark plug are indicated by clean white, often blistered insulator. This can also be accompanied by excessive wear of the electrode, and the absence of deposits.

CAUSE: Check for the correct spark plug heat range. A plug which is too hot for the engine can result in overheating. A car operated mostly at high speeds can require a colder plug. Also check ignition timing, cooling system level, fuel mixture and leaking intake manifold.

RECOMMENDATION: If all ignition and engine adjustments are known to be correct, and no other malfunction exists, install spark plugs one heat range colder.

Carbon Deposits

APPEARANCE: Carbon fouling Is easily identified by the presence of dry, soft, black, sooty deposits.

CAUSE: Changing the heat range can often lead to carbon fouling, as can prolonged slow, stop-and-start driving. If the heat range is correct, carbon fouling can be attributed to a rich fuel mixture, sticking choke, clogged air cleaner, worn breaker points, retarded timing or low compression. If only one or two plugs are carbon fouled, check for corroded or cracked wires on the affected plugs. Also look for cracks in the distributor cap between the towers of affected cylinders.

RECOMMENDATION: After the problem is corrected, these plugs can be cleaned and reinstalled if not worn severely.

MMT Fouled


APPEARANCE: Spark plugs fouled by MMT (Methycyclopentadienyl Maganese Tricarbonyl) have reddish, rusty appearance on the insulator and side electrode.

CAUSE: MMT is an anti-knock additive in gasoline used to replace lead. During the combustion process, the MMT leaves a reddish deposit on the insulator and side electrode.

RECOMMENDATION: No engine malfunction is indicated and the deposits will not affect plug performance any more than lead deposits (see Ash Deposits). MMT fouled plugs can be cleaned, regapped and reinstalled.

High Speed Glazing


APPEARANCE: Glazing appears as shiny coating on the plug, either yellow or tan In color.

CAUSE: During hard, fast acceleration, plug temperatures rise suddenly. Deposits from normal combustion have no chance to fluff off; instead, they melt on the insulator forming an electrically conductive coating which causes misfiring.

RECOMMENDATION: Glazed plugs are not easily cleaned. They should be replaced fresh set of plugs of the correct the condition recurs, using plugs with a heat range one step colder may cure It.

Ash (Lead) Deposits


APPEARANCE: Ash deposits are characterized by light brown or white colored deposits crusted on the side or center electrodes. In some cases it may give the plug a rusty appearance.

CAUSE: Ash deposits are normally derived from oil or fuel additives burned during normal combustion. Normally they are harmless, though excessive amounts can cause misfiring. If deposits are excessive in short mileage, the valve guides may be worn.

RECOMMENDATION: Ash-fouled plugs can be cleaned, gapped and reinstalled.

Detonation


APPEARANCE: Detonation is usually characterized by a broken plug insulator.

CAUSE: A portion of the fuel charge will begin to burn spontaneously, from the increased heat following ignition. The explosion that results applies extreme pressure to engine components, frequently damaging spark plugs and pistons.
Detonation can result by over advanced ignition timing, inferior gasoline (low octane) lean air/fuel mixture, poor carburetion, engine lugging or an increase in compression ratio due to combustion chamber deposits or engine modification.

RECOMMENDATION: Replace the plugs after correcting the problem.

Good info, usually all this shit is in the back of a haynes manual.

this is alot better then the haynes manual. x2

Dont waste your money on those plugs, if you change em, put the NGK's back in

What I was describing with my post was the mmt burn, leaving the reddish brown residue.

so you tell me that the iridium plugs are not good?

Actually in my country we have only one grade of fuel.and i think its the bad grade.

i used to add octane booster in my tank and the engine feels more smoothly,so i would like to know why you tell me the octane booster is not good either?thank you all for replying.

Keep in mind that in octane lingo and / or octane booster lingo, 1 point is 1/10 of an octane #, so 10 points =1 octane, or you just went from 91 octane to 92 octane with a 10 point increase. (Approximately)
I don't think a quart of anything is going to appreciably raise the octane number of a tank full of pump gas.In your lawnmower, it would make a difference, but this stuff is usually Toluene,with a lubricant.
You can buy toluene at most paint stores by the gallon for around 10 bucks and adjust your octane needs that way, i personally have used it in my ZC and i usually mix 8 gallons of gas(93 octane) to 1/2 gallon of toluene on race days which still only nets around 98 octane
Toluene has a RON octane rating of 121 and a MON rating of 107, leading to a (R+M)/2 rating of 114. (R+M)/2 is how ordinary fuels are rated in the US. Note that toluene has a sensitivity rating of 121-107=14. This compares favorably with alcohols which have sensitivities in the 20-30 range. The more sensitive a fuel is the more its performance degrades under load. Toluene's low sensitivity means that it is an excellent fuel for a heavily loaded engine.
Toluene is denser than ordinary gasoline (0.87 g/mL vs. 0.72-0.74) and contains more energy per unit volume. Thus combustion of toluene leads to more energy being liberated and thus more power generated. This is in contrast to oxygenated octane boosters like ethanol or MTBE which contain less energy per unit volume compared to gasoline. The higher heating value of toluene also means that the exhaust gases contain more kinetic energy, which in turn means that there is more energy to drive turbocharger vanes. In practical terms this is experienced as a faster onset of turbo boost.

stick with the stock oem ngk plug. Its what your engine is actually designed around. some hondas call for plats as a factory replacement. i would only use denso or NGK, but if they work well for u then by all means carry on.

APPEARANCE: Spark plugs fouled by MMT (Methycyclopentadienyl Maganese Tricarbonyl) have reddish, rusty appearance on the insulator and side electrode.

CAUSE: MMT is an anti-knock additive in gasoline used to replace lead. During the combustion process, the MMT leaves a reddish deposit on the insulator and side electrode.

RECOMMENDATION: No engine malfunction is indicated and the deposits will not affect plug performance any more than lead deposits (see Ash Deposits). MMT fouled plugs can be cleaned, regapped and reinstalled.
As stated above.

thank you very much for this info.well i forgot to mention that the engine runs with the denso iridium.