How to: Change Spark Plugs?
How to: Change Spark Plugs?
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Joined: Mar 2003
Posts: 1,661
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From: east coast
I just did mine today..its fairly easy if you are slightly mechanically inclined.
First,Strut tower bar comes off..8-12mm bolts
Second tale off the plastic engine cover(says Nissan on it 4 10mm bolts
Third take the intake pipe off
Now you will see the 3 coils on each side of the engine,each one is held in with a gold colored 10mm bolt(be careful not to drop these bolts into the engine..I learned that the hard way..
take the coils out one by one it will slide right out but you may have to move some of the wire harnesses around to get at them and be careful not to bend them too much when extracting them.
now look down the hole and you can see the plugs but you will need a long extension cause they are deep!!!try the drivers side ones first they are a little bit more exposed than the passenger side which you may have to disconnect some vacume hoses and move some wire harnesses around. But the whole project is fairly easy to do..hope this helps.
tools
Spark plug socket(duh!)
10mm
12mm
flathead screwdriver
First,Strut tower bar comes off..8-12mm bolts
Second tale off the plastic engine cover(says Nissan on it 4 10mm bolts
Third take the intake pipe off
Now you will see the 3 coils on each side of the engine,each one is held in with a gold colored 10mm bolt(be careful not to drop these bolts into the engine..I learned that the hard way..
take the coils out one by one it will slide right out but you may have to move some of the wire harnesses around to get at them and be careful not to bend them too much when extracting them.
now look down the hole and you can see the plugs but you will need a long extension cause they are deep!!!try the drivers side ones first they are a little bit more exposed than the passenger side which you may have to disconnect some vacume hoses and move some wire harnesses around. But the whole project is fairly easy to do..hope this helps.
tools
Spark plug socket(duh!)
10mm
12mm
flathead screwdriver
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Joined: May 2003
Posts: 5,566
Likes: 1
From: Valdosta, GA
Originally posted by daking350
I just did mine today..its fairly easy if you are slightly mechanically inclined.
First,Strut tower bar comes off..8-12mm bolts
Second tale off the plastic engine cover(says Nissan on it 4 10mm bolts
Third take the intake pipe off
Now you will see the 3 coils on each side of the engine,each one is held in with a gold colored 10mm bolt(be careful not to drop these bolts into the engine..I learned that the hard way..
take the coils out one by one it will slide right out but you may have to move some of the wire harnesses around to get at them and be careful not to bend them too much when extracting them.
now look down the hole and you can see the plugs but you will need a long extension cause they are deep!!!try the drivers side ones first they are a little bit more exposed than the passenger side which you may have to disconnect some vacume hoses and move some wire harnesses around. But the whole project is fairly easy to do..hope this helps.
tools
Spark plug socket(duh!)
10mm
12mm
flathead screwdriver
I just did mine today..its fairly easy if you are slightly mechanically inclined.
First,Strut tower bar comes off..8-12mm bolts
Second tale off the plastic engine cover(says Nissan on it 4 10mm bolts
Third take the intake pipe off
Now you will see the 3 coils on each side of the engine,each one is held in with a gold colored 10mm bolt(be careful not to drop these bolts into the engine..I learned that the hard way..
take the coils out one by one it will slide right out but you may have to move some of the wire harnesses around to get at them and be careful not to bend them too much when extracting them.
now look down the hole and you can see the plugs but you will need a long extension cause they are deep!!!try the drivers side ones first they are a little bit more exposed than the passenger side which you may have to disconnect some vacume hoses and move some wire harnesses around. But the whole project is fairly easy to do..hope this helps.
tools
Spark plug socket(duh!)
10mm
12mm
flathead screwdriver
Also, do you know the fuel injector size(s)?
Registered User
Joined: Sep 2002
Posts: 212
Likes: 0
From: DFW
Swapped plugs; used a .049 gapp setting
Originally posted by daking350
I just did mine today..its fairly easy if you are slightly mechanically inclined.
I just did mine today..its fairly easy if you are slightly mechanically inclined.
I guess "easy" is relative. It took me almost two hours. Oh well.Here's how the plugs read:
Rear cylinder plugs: tan
Center cylinder plugs: tan with a little black soot (slightly rich condition)
Front cylinder plugs: tan with even more black soot (somewhat rich condition)
These readings are consistent with the design of the stock plenum in that it slopes down from the back to the front, making it more difficult for the middle and front cylinders to get their share of oxygen -- as Doug S. has stated.
Crawford's modified plenum, which I have but not installed, should improve this condition so that the air-to-fuel mixture is more consistent from front to rear.
I installed the new plugs with a gap setting of .049. My experience with after market high energy ignition systems (and I'm guessing that Nissan's direct ignition system has more energy than is typical) is that when the plug gap is too small the engine doesn't idle or run as smooth as it could. If the ignition system can support bigger spark plug gaps, more power and response can be had.
I'm going to reserve my comments for a couple of weeks to allow for carbon to build-up on the new plugs. An engine always runs better with new plugs, although my Z has only 7000 miles on it.
I can say that the idle quality and engine smoothness so far seem to be dramatically improved.
Stay tuned....
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Registered User
Joined: Jun 2002
Posts: 524
Likes: 0
From: Kirkland,WA
I changed my plugs last night to NGK Iridiums. WHAT A PIA! Never again will I attempt this myself... My back still hurts from bending over the engine bay for damn near 5 hours.
There are way too many wires/hoses in the way of the coils. I'm just thankful that I didn't break anything.
The original plugs looked great at 46,500 miles and all had roughly the same color and quantity of deposits. I notice no difference with the new plugs.
Mika
There are way too many wires/hoses in the way of the coils. I'm just thankful that I didn't break anything.
The original plugs looked great at 46,500 miles and all had roughly the same color and quantity of deposits. I notice no difference with the new plugs.
Mika
Originally Posted by kgb
...changed the plugs in the Z today and boy what a pain? I guess "easy" is relative. It took me almost two hours. Oh well.
Here's how the plugs read:
Rear cylinder plugs: tan
Center cylinder plugs: tan with a little black soot (slightly rich condition)
Front cylinder plugs: tan with even more black soot (somewhat rich condition)
These readings are consistent with the design of the stock plenum in that it slopes down from the back to the front, making it more difficult for the middle and front cylinders to get their share of oxygen -- as Doug S. has stated.
Crawford's modified plenum, which I have but not installed, should improve this condition so that the air-to-fuel mixture is more consistent from front to rear.
I installed the new plugs with a gap setting of .049. My experience with after market high energy ignition systems (and I'm guessing that Nissan's direct ignition system has more energy than is typical) is that when the plug gap is too small the engine doesn't idle or run as smooth as it could. If the ignition system can support bigger spark plug gaps, more power and response can be had.
I'm going to reserve my comments for a couple of weeks to allow for carbon to build-up on the new plugs. An engine always runs better with new plugs, although my Z has only 7000 miles on it.
I can say that the idle quality and engine smoothness so far seem to be dramatically improved.
Stay tuned....
I guess "easy" is relative. It took me almost two hours. Oh well.Here's how the plugs read:
Rear cylinder plugs: tan
Center cylinder plugs: tan with a little black soot (slightly rich condition)
Front cylinder plugs: tan with even more black soot (somewhat rich condition)
These readings are consistent with the design of the stock plenum in that it slopes down from the back to the front, making it more difficult for the middle and front cylinders to get their share of oxygen -- as Doug S. has stated.
Crawford's modified plenum, which I have but not installed, should improve this condition so that the air-to-fuel mixture is more consistent from front to rear.
I installed the new plugs with a gap setting of .049. My experience with after market high energy ignition systems (and I'm guessing that Nissan's direct ignition system has more energy than is typical) is that when the plug gap is too small the engine doesn't idle or run as smooth as it could. If the ignition system can support bigger spark plug gaps, more power and response can be had.
I'm going to reserve my comments for a couple of weeks to allow for carbon to build-up on the new plugs. An engine always runs better with new plugs, although my Z has only 7000 miles on it.
I can say that the idle quality and engine smoothness so far seem to be dramatically improved.
Stay tuned....
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