Reading plugs

[Hnichols]

My apologies for yet another spark plug reading thread. But since these were coming out, I had to post them -- do they tell you anything other than that I do too much city driving?

TIA

[SchnellSchweitz]

I can't see all the electrodes clearly, but I believe a nice dusty gray color means they are running right.

[sacoffee]

Like the Poster above they "look" ok, hard to tell ... But #4 looks like some deposits?

Look, the only WTF stuff on plugs is oil, deposits and soot.

[James Brown]

are they from a toyota? can't tell what kind of car. for future use: Spark Plug Information From Wikipedia – StrikeEngine

[Hnichols]

Thanks all. My only question would be the lumps of carbon on #3 and #4.

James: they're from my 3.2. I usually don't post questions about my Toyota here

[sacoffee]

Did you change wires, rotor and cap also? Look at the posts, maybe a poor connection between wire and plug. Awefuly dirty as well.

Are you running premium unleaded?

[James Brown]

make model year engine size, put that in your signature line (and color) so OTHERS know

[sacoffee]

Originally Posted by James Brown

make model year engine size, put that in your signature line (and color) so OTHERS know

Look at his garage

[Hnichols]

Originally Posted by sacoffee

Did you change wires, rotor and cap also? Look at the posts, maybe a poor connection between wire and plug. Awefuly dirty as well.

Are you running premium unleaded?

No, didn't change wires, cap or rotor. But I did pull #4 a couple of months ago (no carbon then) so it is possible I didn't connect the plug properly (?). But the car ran fine. I didn't know that poor connections resulted in carbon deposits.

Yes on the premium unleaded.

[sacoffee]

I asked about the wires because of how dirty the posts are, looks like plug hole covers aren't doing their job

You really should change the wires, rotor and cap

Deposits can be from a lot of reasons - too cold a plug, too large a gap, rich fuel mix and loss of compression.

Your plugs look old, do a complete tune up and pull plugs in 200 miles to see if you are still getting the fouling.

Have you done a compression check?

[T77911S]

you really need to do better pics of them. each one, up close and not blurry and of the business end. then really all we can tell is if you might have ring/guide problems and if one stands out as being worse than the others.
another thing, plugs with a lot of miles are not as usefull as lower mile plugs.
pull them with about 200 miles and take a loo at them.
the motor needs to be shut down at WOT too. idle is too rich and messes up the plugs.

[Steve@Rennsport]

The ONLY way to accurately read spark plugs is by doing whats called a "Plug cut". Once the engine is idling for a moment, anything you see merely displays idle fuel mixture and that's all.

A Plug Cut is performed by running the engine at whatever RPM and throttle position (load) you wish to look at. One drives at your fixed RPM and throttle setting for 30 secs, then abruptly shutting off the engine and depressing the clutch, simultaneously. Then, you remove the spark plugs at the side of the road to look at them.

This gives you an accurate "snapshot" of the engine's fuel mixture (and combustion conditions if you know what to look for).

[Jdub]

Number two appears to be the best one, so I would judge others by that. Number 6 - did it loosen very easily? It almost appears to have carbon riding up the threading. That would be very bad, as a plug can shoot right out of a block if it is not tightened down.

[theiceman]

Those plugs look old and beat .. how about treating your car to new ones and starting over .. they are what a whopping 2 bucks each ?

[ClickClickBoom]

I remember in the olden days a guy named Bobby Strahlman, remember listening to him "reading" Kenny Roberts plugs from the TZ750 at the San Jose Mile, epic days!

[Hnichols]

Thanks, everybody. Yes, they were removed because they were being replaced (as part of a valve adjustment and general tune up). I have no idea how old they are, since the car is new to me. And, yes, I was also surprised at how dirty they were.

Maybe I'll snap a picture --a better one! -- of the new plugs in a month or so.

[rusnak]

Those plugs are absolutely horrible, from a 3.2. Plugs should be pristine and light in color.

[theiceman]

Originally Posted by Hnichols

Thanks, everybody. Yes, they were removed because they were being replaced (as part of a valve adjustment and general tune up). I have no idea how old they are, since the car is new to me. And, yes, I was also surprised at how dirty they were.

Maybe I'll snap a picture --a better one! -- of the new plugs in a month or so.

Good Idea .. with your tune up you should have a good baseline now .. I would throw in a new Cap and rotor now also to complete the spark circuit .. I realize the cap isnt as cheap as my SC but sounds like you need to baseline it all anyway ..

[sacoffee]

This is what they should look like ... a couple were looser than others and some had loose plug wires. These are original to the car as far as i can tell.

very good advice up above, and you really should change wires, rotor and cap.