SA_RX7

Looks as though the upper 2 and lower 2 have different issues. in order of the picture it goes, trail-lead trail-lead.

gopher_6_9

Miles on them? amy running problems?

SA_RX7

slight hessitation on excelleration above 3.5/4 rpms. accelleration feels jumpy and jerky, no that bad tho but enough to notice.

da_toucan

From what I can see on these plugs (in order from left to right in the pic)

The first plug on the left appears to be "blistered", 2nd plug looks fairly normal. 3rd and 4th appear to be oil fouled or low temp fouled

1st Left = An example of overheating is dead white or gray insulator nose which appears "blistered." Electrode gap wear rate will usually be considerably excess of that normally expected. This is often caused by over-advanced ignition timing, poor engine cooling system efficiency (scale, stoppages, low level), a very lean A/F mixture, a leaking intake manifold, or the use of a spark plug too hot for the application.

Right two = Soft, sooty deposits indicate incomplete combustion. Probable causes include over-rich carburetion or fuel injection, weak ignition, retarded timing, or low compression. Other causes include continuous low-speed operation, or, with oil injection systems, gunning the throttle at engine idle speed.

Since you have two very different conditions on these plugs, I would rule out timing or air/fuel mixture issues, and look more closely at your coolant system, and any performance mods you may have completed. If you modded your engine, you may have the wrong plug types. Also consider your driving style... Do you rev the motor at idle to impress your friends? Do you drive like a granny or like Mario Andretti?

SA_RX7

plugs in pic probably over 15k since other tune-up stuff seems over due, 109k total miles, not known if this is original motor tho. Upon first inspection, one of the spark plug gave off no spark, but after moving the wiring around and playing with them, that plug now gives a spark.

da_toucan

definitely sounds like you want to double check the coolant system and replace the plugs AND the wires. This should help. Since it sounds like you just bought this one, and it runs decent right now other than the acceleration issue, after you replace the plugs and wires, Check the plugs again after about 2000 miles to see if you have the same condition on them.

SA_RX7

Thanks, very detailed, if anything, I learned alot from this post. Umm, just aquired a month ago, only drove 200 miles in it. I do spirited driving, so no reving, racing, dont do granny rpms, know that bad for the plugs.

SA_RX7

i replaced the plugs and there's about 30 miles on the new ones and that black buildup is already on them?

da_toucan

black after 30 miles?
One of two probables.... oil fouled or too cold. Oil fouled are caused from oil in the combustion chamber.
Too cold can be caused by using high temp plugs that don't get hot enough to burn off the excess buildup, or from a poor spark condition.
You mentioned a plug not sparking very well until you played with the wire a bit. Make sure you've replaced your wires, and use the appropriate temp rated plugs, and a compression test wouldn't hurt either. If the Apex seals are worn, compression could be lower than normal.

I'm not a certified mechanic or anything, but I'm a pretty experienced garage bay tinker man who's read a lot of books, manuals etc. and had more than my fair share of projects. (I tend to be cheap so I buy fixer-uppers which require lots of tinkering.)

RETed

What is the order of the plugs?
If the left two are leadings and the right two are trailings, those look perfectly normal to me.

If you got them alternating leading - trailing - leading - trailing, then we got a problem...


-Ted

SA_RX7

wires changed...seems to be running smoother, not hesitating and no odor as it had before. Gotta figure out the temp rating on the plugs. My sa 1st gen, i have to get special order so I was forced to choose the temp rating, but the fc had them at pep boys.

SA_RX7

Hey Ted, I'm born in honolulu, raised in eva and pearl city.

Any way, the pic is alternating L-T-L-T If your facing the spark plug side of the motor, the black colored ones came from the 2 top spark plug holes. The gray ones are from the bottom 2. Now what??? Thank you

RETed

High cost of living chased you away?
Hope you're safe in Torrance!
Not exactly the best neighborhood in Cali...

Ok, I confused...
The left two look TAN.
The right two look BLACK.
Or my eyes deceiving me?

The trailings are usually more black cause they are colder heat ranges.
That's normal.


-Ted

dw89s5

wait and see if u have the same problem could have been just the wires keeping the plugs from firing the way they should

mindfungus

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