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How to change your sparkplugs

366K views 261 replies 97 participants last post by  Teawrecks 
#1 ·
Figured this might be helpful for somebody. First you'll need to properly gap your selected spark plugs- factory calls for .028-.031 gap, yours may vary depnding on model ie iridium or needs. Lots of info out there on choices of plugs- I won't go into any of it here.

You'll need to use some kind of gapping device and you'll want an accurate gap. Here's the tool I use:
 
#2 ·
We'll start on the drivers side, but first we'll have to make some room. The battery as well as the washer needs to come out,

Two 10mm nuts on the battery, two 10mm bolts on the washer bottle and a connector:
 
G
#184 ·
I know this is all kinds of ancient...but how did you get the WRX logo on the intercooler? I love it! Brilliant idea! Where did you get the WRX decal thing? I'm guessing you can just get a cutout and then spray paint the logo on the intercooler?
 
#222 ·
Coil pack removal



Sorry I'm so late to the game. Is there any reason why the connectors have to be removed? Is it possible to remove the bolt holding in the coil pack and pull it out, carefully?

This looks like a great post and I am going to perform this maintenance myself this weekend.

Thanks Team!
 
#12 · (Edited)
Your now ready remove the spark plugs. Use the spark plug socket on a extension, gently put it into the "hole" until you firmly have the spark plug on the socket. Using a ratchet remove the spark plug- shouldn't be in there too tight.


We can now put your properly gapped new spark plugs in. Use the flex spark plug socket and a extension. You may want to put a light coating of antiseize on the threads. Gently start the plug in using just the extension, tighten firmly by hand. You'll then put a ratchet on the extension and tighten to 15 ft lbs- you likely won't be able to get a torque wrench in there, so tighten carefully -15 ft lbs is not that much.
 
#13 ·
Next the coil packs go back on. Slide the boot portion over the spark plug, gently snugging it on- you'll feel it going on. Once properly on, tighen the coil pack bolt to 12 ft lbs- again a torque wrench won't likley fit so go careful- 12 ft lbs is not that much. Next reconnect the connectors to the coil packs.

We're ready to move to the other side:

First remove the air scoop, two 10mm bolts:
 
#14 ·
Next we'll remove the airbox. We'll disconnect the hose connecting the airbox to the turbo inlet hose. Then we'll disconnect the connector to the MAF sensor (see pic). Then we'll remove the upper half of the air filter w/ the filter.
 
#20 · (Edited)
Reinstall all the pieces you have removed. Hooking up the battery last.

Check your spark plugs for unusual color- lot's of good sites explaining the different colors and conditions.

You have effectively reset your ECU by disconnecting your battery, which means the Advanced Multiplier (AM) is set back to 8, you want it to get to 16. You can do this quicly by gently driving (no boost) until you have a place you can get into 3rd gear- accelaerate slowly, left foot braking (puts load on) keep boost at ~ 2-3 psi for ~ 20-30 secs and it should be there. Ofcourse if you have a Delta Dash, you can tell for sure.

Happy driving.

Big Sky
 
#21 ·
AjIsDope said:
Very nice writeup BS.

What model NGK plugs did you use?

How often do you change your plugs when running higher boost?
I'm using the copper, one step colder- part # BKR7ES-11. They come gapped at ~ .043 so you have some closing up to do.

I change plugs every 12,000 miles. Platinum's can go longer.

Big Sky
 
#25 ·
Big Sky WRX said:
I'm using the copper, one step colder- part # BKR7ES-11. They come gapped at ~ .043 so you have some closing up to do.

I change plugs every 12,000 miles. Platinum's can go longer.

Big Sky
12k miles!!!! subaru says 60k (platinum)
 
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