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View Full Version : Fouled Spark Plugs at 1600 miles



Stormtrooper
11-10-2008, 07:53 PM
With Bryan's help last weekend (his tune feels great!) we discovered that my spark plugs were fouled...

My car only has 1600 miles on it, yes 9.X AFR didn't help the matter, but I was wondering why other evoX guys didn't having the same issue. Well, I asked around and the topic of my driving habits came up and I think we have the answer so I guess this thread might be more of an FYI...

I found this at a general EFI/ignition FAQ page:
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When replacing spark plugs, the heat range must be correct for the engine application. Always follow the vehicle or spark plug manufacturers recommendations. If the plugs are too cold, fouling may occur if the vehicle spends a lot of time idling or is used only for short trips (especially during cold weather). If the plugs are too hot, the engine may experience preignition and detonation under load or during hot weather.

In some situations, a slightly hotter or colder plug may be installed than the one normally recommended. Switching to a slightly hotter plug can help reduce fouling in an older engine that uses oil. A hotter plug can also reduce fouling in vehicles that spend a lot of time idling or are used only for short-trip, stop-and-go city driving. But a hotter plug should not be used unless an engine is experiencing a fouling problem because of the increased risk of preignition and detonation.
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Well I live about 4 blocks away from work (I would walk, but i still need my car during the day for meetings, etc.), so my morning and night drive back home are about 1/2 a mile. In other words, my car doesn't even get close to being fully warmed up. My car is most likely not even coming out of cold start open loop conditions, so all these conditions together:

- Short drives to and from work: Plugs don't have time to warm up...The constant rich open loop conditions are coating the plugs with fuel deposits which are normally burned off once the plugs warm up. As a result, the deposits probably just kept building up.
- Stock evoX spark plugs are '8' range.... 1 step colder than the CT9A evos which had '9' range.
- Pig Rich stock tune!

comments, other ideas?

dabaysevo
11-10-2008, 08:37 PM
Bounce off the limiter in 1st going to work, problem solved. They'll be nice and warm in those 4 blocks. Well now that you are tuned, maybe you wont have the problem happen again with the second set of plugs.

Kings Fan
11-10-2008, 08:44 PM
Find a job that is further away

chrisw
11-10-2008, 08:56 PM
Find a job that is further away


or ride a bike to work.

Unowned
11-10-2008, 09:01 PM
leave earlier for work and drive around for a bit

Stormtrooper
11-18-2008, 02:34 PM
changed them out... car runs smoother high end now and idle is smoother. When the car is cold the car runs noticably smoother now too!

If the pic doesn't work:
http://lh4.ggpht.com/_OEDh_sd6oS0/SSMzruXuM3I/AAAAAAAACsE/_qEqNBNMFqw/s640/fouled.jpg

MightyPhantom
11-18-2008, 06:08 PM
Where'd you get the new ones from??

Boostd4
11-18-2008, 06:32 PM
Interesting...I'll have to pull mine just to see what they are up to...I have 7K on the car, but it seems fine.

Stormtrooper
11-18-2008, 07:58 PM
Where'd you get the new ones from??


Mitsubishiparts.net

MightyPhantom
11-18-2008, 08:17 PM
Thanks. :wink:

earlyapex aka jack ass
11-18-2008, 09:35 PM
I updated the spark plug listing to include Evo 10:

http://www.norcalevo.net/forum/index.php/topic,20752.msg314795.html#msg314795

Unowned
11-19-2008, 05:10 PM
i have fouled plugs and it screwed up my tune :(

Storm, did you need to regap the plugs on install or they came speced correctly?

drewm
11-20-2008, 12:27 PM
You should always re

i have fouled plugs and it screwed up my tune :(

Storm, did you need to regap the plugs on install or they came speced correctly?


You should always regap. The last time I got plugs they were all pretty far off, even though they came from the dealer "pre gapped"

earlyapex aka jack ass
11-20-2008, 01:03 PM
just remember, NEVER TOUCH THE ELECTRODE on iridium plugs when gapping.

Devin@SpeedElement
11-20-2008, 01:32 PM
HKS got plugs for the EVO X ... stock heat range and 1-Step colder :)

Unowned
11-20-2008, 04:25 PM
HKS got plugs for the EVO X ... stock heat range and 1-Step colder :)


perfect for that just released FP Red Turbo

dabaysevo
11-20-2008, 08:21 PM
just remember, NEVER TOUCH THE ELECTRODE on iridium plugs when gapping.


What do you mean? With your hands or with the gapping tool?

earlyapex aka jack ass
11-21-2008, 12:27 AM
just remember, NEVER TOUCH THE ELECTRODE on iridium plugs when gapping.


What do you mean? With your hands or with the gapping tool?


Gapping tool, it's really easy to break/crack/bend