Spark Plug Installation
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Spark Plug Installation
I never installed spark plugs before and It looks difficult on the subys. Anyone know how much they charge just for installation of spark plugs if you purchase them yourself. I asked around and some dealers won't even install it for me and others charge me $80 just for labor. Thanks
Youie
Youie
Registered User
Joined: May 2003
Posts: 175
thats ridiculous that the dearlers wont replace your plugs. they charge 2 hours for labor... thats insane. i did mine in about an hour, its not hard at all. the spark plugs them self from the dealer are no cheap. id go with iridium , they are similar in price with the stock plugs from subaru.
heres how to do them yourself:
-remove the windsheild washer bottle
-remove the intake air box
-they are kinda tricky to find but if you look down the side, you'll see two little black boxes on each side of the motor a little below where the intake manifold meets the head. wrx 's use coil on pack and its held on by i htink it was a 10mm bolt, may be two youll have to dissconnet the harness for each coil, you cant miss it. do them one at a time you may mix them up. i believe there were white and yellow dots on them so you dont but do them one at a time.
-then youll see the spark plugs after your remove the coil.
-on the number 3 cylinder, there is the o2 sensor mount on the coil, MAKE SURE YOU DONT FORGET THIS WHEN YOU PUT IT BACK!
- make sure you let the car cool down for a few hours and DO NOT OVER TIGHTEN THE PLUGS!
it may sound kinda difficult but its really easy with the right tools.
you will need a 3/8 rachett , sockets, and a swivel will save you a lot of time.
heres how to do them yourself:
-remove the windsheild washer bottle
-remove the intake air box
-they are kinda tricky to find but if you look down the side, you'll see two little black boxes on each side of the motor a little below where the intake manifold meets the head. wrx 's use coil on pack and its held on by i htink it was a 10mm bolt, may be two youll have to dissconnet the harness for each coil, you cant miss it. do them one at a time you may mix them up. i believe there were white and yellow dots on them so you dont but do them one at a time.
-then youll see the spark plugs after your remove the coil.
-on the number 3 cylinder, there is the o2 sensor mount on the coil, MAKE SURE YOU DONT FORGET THIS WHEN YOU PUT IT BACK!
- make sure you let the car cool down for a few hours and DO NOT OVER TIGHTEN THE PLUGS!
it may sound kinda difficult but its really easy with the right tools.
you will need a 3/8 rachett , sockets, and a swivel will save you a lot of time.
Registered User
iTrader: (12)
Joined: Nov 2002
Posts: 18,369
From: Reno, NV
Car Info: 1993/2000/2001 GF4 mostly red
I would recommend NGK copper plugs over the Iridiums. Those are just really expensive but don't make as good a spark. They are used because they last a really, really long time, whereas coppers need to be replaced every 15k or so. Most of us find this acceptable since doing them is easy, and they are only about $1.29 apiece. 
I'm confused about the o2 sensor thing though- are you referring to a clip for the wire going to it? Because there is no exhaust gas going through the coil...
I'm confused about the o2 sensor thing though- are you referring to a clip for the wire going to it? Because there is no exhaust gas going through the coil...
Registered User
iTrader: (2)
Joined: Nov 2002
Posts: 1,644
From: Lawrence, Kansas
Car Info: 19' Impreza Sport Manual / 99 Miata / 13' OB
Look at this link I have pics:
http://www.scoobymods.com/forums/sho...=&threadid=166
Here for a wrx:
http://www.scoobymods.com/forums/sho...&threadid=1596
Both links are good to look at though.
Peaty
http://www.scoobymods.com/forums/sho...=&threadid=166
Here for a wrx:
http://www.scoobymods.com/forums/sho...&threadid=1596
Both links are good to look at though.
Peaty
Registered User
Joined: May 2003
Posts: 175
you dont remember that little hanger for the o2 sensor on the number 3 cylinder? ... yea, i believe its the front o2 sensor wire. it bolts with the bolt that holds the cap over the spark plug in place. i guess it would be ok if you foget it but it possibliy could get damaged if its not secure.
but yea the iridiums will last a very long time. but then again replacing them isnt hard at all.
but yea the iridiums will last a very long time. but then again replacing them isnt hard at all.
Registered User
iTrader: (2)
Joined: Nov 2002
Posts: 1,644
From: Lawrence, Kansas
Car Info: 19' Impreza Sport Manual / 99 Miata / 13' OB
I've used them in our OB 2.5 I really don't think they are worth the extra money. When I removed them after 30K it was obvious that only one of the electrodes was doing the work. I say stick w/ NGK OEM's
Registered User
Joined: Jan 2003
Posts: 555
From: Bethlum, PA
Car Info: silver 2.5 tr 2006MT wrx
i tried the 4's i do not think that they actually helped, i think they were worse, i got a set of platniums for like 1.30$ gapped and i think they work better, there is none of the noticable black soot on the tail pipe like there was on the bosch 4's, they worked great in my escort though. get the regular plugs, get the right gap .44 i thnik it is.
one think i am interested in though is the high votage coil packs, and the wires, are they really gonna help a na engine.
one think i am interested in though is the high votage coil packs, and the wires, are they really gonna help a na engine.
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Need some advice on plugs. I have heard though that the Bosch Platinum 4 is not really a performance plug, it's just meant to produce better spark and regulate the spark but does not boost the performance by much. is it true? What is the diff between HKS Super Fire plugs, compared to with Blitz, GReddy and A'PEXi? Any significance in performance gains from one to another? Thanks guys
www.SpeedXS.com - Center for *** Performance Cars
www.SpeedXS.com - Center for *** Performance Cars
Registered User
iTrader: (2)
Joined: Nov 2002
Posts: 1,644
From: Lawrence, Kansas
Car Info: 19' Impreza Sport Manual / 99 Miata / 13' OB
Spark plugs will not give any gain in performance, the wrong one old and worn ones will make it worse though.
From here:
http://www.ngksparkplugs.com/techinf...200&country=US
Frequently Asked Questions
Q: How much of a performance improvement can I expect from changing plugs?
A: A common misconception is that changing spark plugs will result in a large power increase. In most cases, removing even seriously worn out spark plugs will only result in very modest power gains, typically about 1-2% of total engine output. This could be even less for computer-controlled vehicles, primarily because most newer vehicles have more powerful ignition systems and the vehicle's computer can make adjustments so that vehicle operation seems smoother and more seamless.
Many people think that simply supplying more spark to the firing tip can and will combust more fuel. What they don't understand is that most newer cars' engines are so efficient that they are already burning all of the available fuel. Simply adding more spark voltage can't burn more fuel because there is no more fuel to burn.
When a stock or near-stock engine is given a fresh set of spark plugs, peak efficiency is restored. The power gains that come from this restored state of tune are usually minimal. Any company that tells you that their spark plug will provide significant gains in power in a stock or near-stock engine is making blanket statements that may not be supportable.
Q: How much of a performance improvement can I expect from changing plugs?
A: A common misconception is that changing spark plugs will result in a large power increase. In most cases, removing even seriously worn out spark plugs will only result in very modest power gains, typically about 1-2% of total engine output. This could be even less for computer-controlled vehicles, primarily because most newer vehicles have more powerful ignition systems and the vehicle's computer can make adjustments so that vehicle operation seems smoother and more seamless.
Many people think that simply supplying more spark to the firing tip can and will combust more fuel. What they don't understand is that most newer cars' engines are so efficient that they are already burning all of the available fuel. Simply adding more spark voltage can't burn more fuel because there is no more fuel to burn.
When a stock or near-stock engine is given a fresh set of spark plugs, peak efficiency is restored. The power gains that come from this restored state of tune are usually minimal. Any company that tells you that their spark plug will provide significant gains in power in a stock or near-stock engine is making blanket statements that may not be supportable.
http://www.ngksparkplugs.com/techinf...200&country=US