What is the correct spark plug for 2009 CX-9 GT (2wd) - sp 411?

texas_cx9

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CX-9
I wanted to confirm the spark plugs for a 2009 CX-9 GT (2wd). Since this is a Ford engine with Ford parts everywhere, and Mazda had a delay to get spark plugs, I used the numbers off the plugs to get them from Ford directly.

My plugs show: AYFS 22FM (with 8L sideways, don't know what this number is)

Ford gave me:

sp 411 (which have the same number across them). But are these 100% exact???

I gaped them to .051 per owners manual. I am trying to chase down cold start up detonation (goes away when it hits normal op temp). Want to make sure these are not hotter than required. But I did have the detonation before the plug change. Gap on 100K miles for plugs was .080 (crazy!!!).

Thanks.
 
the "8L" is a date code from when the plug was made.

8=2008
L= November
 
Thanks Mazdadude. You have an insane list of Mazda's you have owned. Very impressive.

One more question. You agree these are the right spark plugs. No reason to think they could be cold detonation (unless I messed up the gap)?

Thanks.
 
LOL! Believe or not, I have had about a dozen other cars from other makes too, but I always come back to the Mazdas...

Yes the SP411/AYFS22FM are identical.

I worry about the gapping procedure used on those new plugs... It really should have been preset, and no need to adjust. Did you use a coin/ramp style gauge>?

Also, FYI, as a curiosity, according to the ROCK AUTO Catalogs, there is a different spark plug utilized on the 2008 model year CX-9 3.7L, which would be a SP478/AZFS32FE. This other SP478/AZFS32FE plug looks to be deeper reach, 1 step hotter heat range and does not have nickel shell, according to this Motorcraft Spark plug chart.

http://jimsprojectgarage.weebly.com/motorcraft-spark-plug-information.html
 
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So sounds like we are OK on having the right plugs. As far as the gap, I just checked each one. One or two were not perfect, so I redid them carefully with the loop ends gapper.

I am not sure what has been causing the detonation if it was not the plugs. The only other thing I can think of is carbon buildup (perhaps a sea foam round is in order). I know it is detonation for a couple reasons besides a keen ear for it:

- It only happens when it is 60 or below in the morning.
- It goes away the moment the engine hits the mid line on temp (standard operating temp). As I understand it, there is some type of knock sensor that comes on when warmed up. If true, this explains it.
- If I put super unleaded, it never happens
 
texas_cx9, no worries. When I changed my plugs I was all worried about the exact gap but I gapped them somewhere in the middle of the acceptable range per service manual. Have put on thousands of miles since (about 18k or so) with no issues.
I have your same exact pinging/detonation problem too, always have. Its the gasoline. I have gotten it to go away temporarily sometimes but only after a can of sea foam in the gas tank and several fill ups of 89 octane or better. I have determined that the 3.7 just does not like 87 octane. It doesn't play nice. If you are coasting through a neighborhood say 25 or 30mph and you sorta tap the gas pedal and hear that noise briefly that sounds like marbles banging together, that's just the timing of the motor which mixes poorly with the ignition involving crappy gas. But like you, if I accelerate up a hill or what not while motor is cold, it pings slightly with moderate acceleration, and then when the needle is centered, it is gone. I don't even think about it anymore. 98k now on the ticker and its never gotten any worse. I just throw in sheetz/speedway gas and every oil change toss in a can of sea foam and maybe fill up with 89 now and then.

When it was still under warranty, I took it in for this issue, threw a temper tantrum and convinced them it fell under emissions warranty and they updated the software on the ecu, but it didn't seem to change anything.

If you haven't actually changed the plugs yet - a word of advice. Let it sit overnight before doing it. I didn't wait long enough and messed up the threads of the last plug and had to force it down with a torque wrench. Hoping it never explodes out of the hole and shoots through the hood. Aluminum doesn't like to be at all warm for plug changes. Likes to be cold.
 
thanks helbigtw. Looks like we both have that same PITA detonation when cold. It is funny. I also took it in around 60k (have 106k now) and got them to flash it to the latest program (which had a note about cold detonation issues). Didn't do a damn thing. It is not rocket science to program the warm up loop to a bit less timing. But seems for whatever reason (sometimes it is perhaps some specific part of an emissions certification), they don't fix it (although detonation is a poor burn). It really ticks me off and they MUST KNOW about this issue. But like you, whatever at this point. I just use higher octane in the winter and eat the extra cost. I am in Texas, so it is not so bad. It has been a great vehicle otherwise.

I did just change the plugs when cold, so all was good with the threads. Thanks for the heads up.
 
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