Just replaced all spark plugs on my CX-9, NGK Iridium IX plugs.
Using the info on this forum, I replaced out my spark plugs on my 2009 CX-9 @ 110,161miles.
This was what I did...
1. Disconnect and remove battery. Put aside.
2. Undo oil filler cap. Put aside.
3. Holding engine cover on the top center position with one hand and near the oil filler with another hand, slowly pull out the cover – which is held by 2 rubber grommets at the top and the rubber ring at the oil filler pipe.
4. Place cover aside and re-secure oil filler cap.
5. There is a rigid hose running next to the oil filler to the air filter housing assembly. Remove by pushing on white tabs sideways (identical on both ends of the hose). Put aside.
6. You may now start on the front bank of spark plug removal.
7. Use compressed air (or canned air if you don’t have a compressor) to blow away any loose dust/sand. If necessary, use a slightly damp rag to wipe down and blow again. This is to prevent any loose debris/dirt falling into the spark plug holes.
8. Undo spark plug electrical connectors. These are really fussy ones with double-locking feature. Slide out red tabs (these are easily broken, especially with age, take extra care). Once out, press down on black tabs and pull plugs out. I used a light tapping motion with a wide flat blade screwdriver to assist. This is a very important “learning” step because you will need to be good at this when you work on the rear bank of plugs.
9. Undo bolts on each coil. Slowly yank out the coils, use a big flat blade screw driver to assist in levering out gently.
10. Undo and remove spark plugs. (I remove one and immediately replaced it with a new one to minimize “exposure time” on each cylinder).
11. Lightly coat new spark plug body end with boot protector grease, and thread with anti-seize.
12. Screw in spark plug hand tight.
13. Use torque wrench, set to 133 pound-inch, tighten plug.
14. Reinstall coil, and bolt holding coil, at 89 pound-inch torque.
15. Repeat 2 more times for other 2 front plugs.
16. Now for the rear bank (complicated part)…
17. Removing air filter box cover:
a. Open air filter box, remove air filter, put aside.
b. Undo MAF sensor connector on air filter cover. Again, use extra care with those red tabs. If you break one, not the end of the world, it’s just a secondary lock.
c. Undo jubilee clips that secures the big rubber air hose to the upper air intake assembly.
d. Undo wire harness clip on left corner of air box cover.
e. Slowly rotate out the filter box cover (back and forth motion). Put aside.
18. Removing air intake resonance chamber assembly (the one with the big triangular box).
a. Pull out small vacuum hose that attaches (just by friction) to the right side (with you facing engine) of the air filter upper assembly.
b. Undo jubilee clip securing big rubber upper air hose.
c. Slowly rotate out upper air intake assembly (back and forth motion). Put aside.
19. Undo bolt under throttle body.
20. Undo valve sitting on top of engine (for access purposes) by undoing 2 nuts – due to the location of these nuts, be careful not to drop it down the engine, put magnetic pick up tool next to nut as you undo the nuts. Put nuts aside, take valve off brackets.
21. Undo bracket holding hose (with “fishnet stocking”) located on the firewall behind the battery:
a. Use a plier, pull out cable holder.
b. Undo black nut securing bracket. Put aside nut.
22. Undoing “fishnet stocking hose”.
a. Using a pair of pliers, grab spring hose clip (on the backside of bracket) that holds the “fishnet stocking hose” connected to intake manifold. Slide clip back by an inch or so.
b. Using a pair of pliers, grab on to hose gently and rotate out hose (back and forth motion).
23. Undoing manifold:
a. Using a pair of needle nose plier, grab and compress 2 plastic expansion rivets that secures a wire harness to 2 points on the manifold. Pop them out.
b. Using a box cutter, slide under and cut electrical tape that secures a wire harness to the right corner of the manifold (you will need to re-tape this with new electrical tape later).
c. Undo 6 bolts holding the manifold. They are not all the same length, so put them aside in an orderly fashion so you know which is which.
d. Undo another electrical plug that connects to the throttle body – be careful not to break the red tabs.
e. Grab manifold on the left side and with a quick yank, break the seal. You should now be able to partially lift up the manifold.
f. Take a clean microfiber towel, slide UNDER the manifold to cover the now exposed air intake channels. This is a safety step to prevent things accidentally dropping in.
g. Pulling on the left side of the manifold, slightly rotate assembly towards you, exposing a rubber hose at the back of the manifold that is connected to the engine.
h. With manifold partially rotated out, grab on to the rear hose and slowly disconnect it on the engine side.
i. Rear bank of spark plugs are now accessible.
24. Repeat steps 7-14 for rear bank of spark plugs. Your newly acquired knowledge from removing the front bank of plugs will be tested here as you need to lean into the engine to reach the rear bank. Be careful NOT to lean on the AC pipe that is located on the left side of the engine.
Your biggest challenge will be the plug on the rear right side. Use the magnetic pickup tool trick to avoid accidentally dropping the bolts.
My old plugs - they actually look okay for 110,161 miles!
25. Installing new gaskets:
a. Without the need to remove the upper manifold from the engine, prop up the manifold with a tool – I used a socket extension tool with a spark plug socket.
b. Using a pick, slowly remove old gaskets being careful not to scratch or damage other surfaces.
c. Using your bare fingers, install new gaskets, starting with the rubber “tab”, working slowly around the “8” figure.
d. Repeat 2 more times for the other gaskets.
26. Reinstall manifold:
a. Remove cloth covering the air inlet holes. Observe the mating surface (where the gaskets fit). I took the opportunity to clean it up a little by wiping with WD-40 and a microfiber towel.
b. Slowly rotate manifold back, but before rotating back fully, grab hold of the rear hose and re-insert to the hose fitting on the engine side.
c. Reposition “fishnet stocking hose” back to the original position.
d. Seat manifold properly, hand-tight screw in all 6 manifold bolts – paying attention which bolts goes to which hole.
e. Tighten bolts to 89 pound-inch – in the order: middle front, middle rear, left rear, left front, right rear, right front.
f. Reverse steps 20b to 17.
27. Finishing off
a. Reverse steps 5 to 1.
Hope this helps!
My car had no negative symptoms before, old spark plugs looked fine. I haven't pushed the car hard since putting the new plugs in. But it appears I'm the only one here opting to use NGK IridiumIX plugs. Will come back to report on performance differences (if any).
Thanks to other contributors on this forum for the info I've incorporated into this post.
Update: although I have no instruments to confirm this, but the CX-9 seemed more responsive now, especially going from 2800rpm-4000rpm. Might be psychological; who knows...