Hi all,

I've been searching the forum for the last 30 minutes to find my answer but I guess I can't word it correctly. I'm sure its on this board somewhere... anyhow...

When investigating an engine issue the other day, my cousin suggested that I check to see if I'm getting a spark from my plugs. We removed 1 wire to check. And we got no spark. Upon removing the wire from the plug itself, I found a plug with a tip so rusted that it looked like I dug it up out of the ground. After checking the rest of the plugs, they were all OK. So my question is (aside from my other engine issue, which is already being resolved) would 1 spark plug not firing cause a drop in engine performance or responsiveness? What would be the effect of a spark plug not firing?

I'm no mechanic at all, so I'm just curious because its obviously been that way (likely) since I bought the car 2 years ago.

Again sorry if the answer to this is already on the forum, if so and you can find it a link would be great too. Thanks!

 

Was the plug wire really easy to pull off (like it almost fell off to the touch)?
The plug wire may not have been "clipped" on.

Yes... poor ignition can cause performance issues and incomplete combustion can also decrease the life of your catalytic converter.
Its also a good idea to use dielectric grease on the wire boot to seal out moisture and prevent corrosions.
Might be a good time to change out the plugs since its been at least 2yrs... so who knows how long its been.

 

A little Anti-seize on the new spark plugs always helps.

USE IT!

 

It wasn't very easy to pull off, was more like it was rusted together... in fact when I was under the car all that rust fell in my face when I did get it off lol. I have a feeling they (prior owners or factory) forgot to add something like dielectric grease as you mentioned. I do plan on doing this when I install the new plugs. I already purchased NGK Iridium. Going to go ahead and replace all 4. Haven't gotten the new wires yet, but I'll need them too.

Thanks for the info, I'll make sure I pay closer attention to the car from this point forward, especially now that I've messed around under the hood a bit and read allot more info on this forum. I feel like I know a little bit more about how to keep it up and running anyway... :P

Hopefully when I get it back going I'll notice a difference

Easy_E1 - 10-4, will do!

 

Poor spark ability or no spark at all may cause a rich mixture witch will destroy/wash out the oil film and will damage your cat. Ok the cat can be replaced but the destruction of oil film may lead to premature wear of seals/housings etc.

 

Rust build up is a comon problem, I wish the former owner of my car knew that, or at least his mechanic at the stealership! Coil failure is VERY common. I had to replace spark plugs, wires and all coils, with 60K mi on my ride, but WOW what an improvement it made! I even gained fuel economy (not that were worried about that). Remenber dielectric grease goes between the top of the plug and the wire, and anti-sieze goes on the threads. Another note; the leading coils do not produce spark durring cranking (or under 300 rpm) so spark needs to be checked while the engine is running. Use an inline spark tester-don't get shocked!! Good luck

 

BTW good point about being sure the wires "clip" on. Also remove the left front tire and u won't have to lay on the ground trust me it is easier as long as u have a jack and stands

 

The rusty clip is an interesting observation and needs replacement but is not diagnostic in and of itself. You'd be surprised what that 40,000 volt spark can jump through. To gauge how the plug is/was performing, you need to observe the business end of the plug itself, particularly the ceramic insulator that surrounds the base of the center electrode. If the car is running well, the center insulator will be a tan color. A serious misfire would result in a black or black & oily appearance.

 

^ Except in a rotory RX8 where the plugs are always black due to pig rich factory setting.

 

When I found the rusty clip on my 8, the coil was not firing remember spark needs to be tested with the engine running, use a spark tester, and be very very carefull not to get electricuted! If u think it runs good now, u can't believe how well it will run on both rotors!! Trust me when the coils are removed u will see how blistered and burned they are. I constructed a heat sink for mine. Oh and use dielectric grease where the coils contact the bracket, it helps with heat transfer

 

BTW "Nubo" is right, the rusty clip was hooked the spark plug that was black and oily, the rest were clean, with a light tan color, but replace them all

 

"Razz1" 's 8 has a problem, probally low compression

 

Mine wasn't black, I just replaced it couple hundred miles ago.

it was tan, a tiny bit of black. thats about it.

you need to drive your baby harder man ... mu ha ha !

 

Drive it like you stole it!

 

Make sure you are judging by the center insulator. Lots of people get hung up about the appearance of the outer electrode, which usually is carboned and on rotaries is gunked up with ash deposits, because that metal is in direct contact with the housing and doesn't get hot enough to burn off deposits. The center insulator is where to look. If it's black you have problems.