DIY: Changing your 4G93 Spark Plugs


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You'll need a couple of tools. My set is all 1/2", but that doesn't matter.
- 8mm socket
- 10mm socket
- 16mm long narrow socket for the spark plugs
- bit of bluetac/sticky tape
-new spark plugs (NGK: BKR5E-11 or BKR5ES-11. The "S" denotes a flat tipped center electrode, the lack of "S" is a V-Groove). The "-11" is the gapping of the plug; our plugs should be gapped to 1.1mm, some will not be gapped already, e.g. BRK5E.

1) Remove the wiring connections from coils 2 and 4 (green). From memory, the coilpacks are a 8mm or 10mm. Remove, and keep the screws somewhere safe (circled red). Depending on how good you are, remove the leads as well (orange) - If you're careful, you can remove the coils with the leads still attached.

2) It'll look like this. Get some compressed air, and blow into the spark tubes. Skip the next sentence if there is oil in the tubes: If you dont have a compressor or a can of air, close your eyes and blow into them quickly. This is to clear any debris (dirt etc) in the tubes to prevent it falling into your combustion chamber. Have a quick look to see if theres any massive bits left over.

3) You can get dedicated spark plug removal tools, but i found some don't fit into our spark tubes. I use a 16mm narrow socket with an extender and it works find.
Loosen the plug by hand, and then do another 5 turns to undo (they always seem to take ages to loosen), and then pop the bit of bluetac/stickytape inside the socket to simply pop into the spark tube and pull the plug out.

4) Check your spark plug for any signs of abnormal wear. Mine looked average a week ago, but since then it is possible to drive and have the spark "burn off" any crud on there, so mine aren't too bad just a little oily/dirty, and for $6/plug they're cheap enough to replace.
This is a list of conditions, realistically a mix of all of them are good/used plugs

6) New plugs to go in. I check them quickly before installing:

7) Its a good idea to check all plugs together for any overall signs of issues (example, bad fuel), as well and individual cylinder issues (example, blocked injector making the spark way too hot).

8) Reinstalling: Pop the spark plugs in. I do this with the socket and extender only, and tighten by hand as tight as possible, and then only end up with a turn or so with the socket. DONT do them too tight, because you'll crack the porcelain (the white part). Some people use anti-seize, i dont. The plugs get the cream from factory anyway, but it holds onto any dirt that falls down there, so you have to be careful. Overtightening will cause it to seize up as well.

Pop the coilpacks back in, install the screws, and pop in the leads, and the electrical connected. Start the car up, and bye bye any missfires


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could also use one of the leads to slowly put in the spark plug rather than blu tack but either way it works


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Not entirely off topic, where the hell does one procure a can of compressed air from? Such a thing would be very useful for blowing dust out of air filters also.


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Not entirely off topic, where the hell does one procure a can of compressed air from? Such a thing would be very useful for blowing dust out of air filters also.

I might be wrong, but i think computer shops sell them for cleaning motherboards and such.