Mazda CX-7 Fuel Type

ratgirlratgirl Member Posts: 2
edited April 2014 in Mazda
We purchased a new 08 a couple months back, and were told that with the 08's, you no longer needed to use premium gasoline - that that was one of the major changes that were made. Also, the dealership mechanic ( who was elderly and appeared to be one of those very wise mechanics that know so much more than the young guys) told us that whichever fuel type we chose, to stick with it. don't change, don't try to use regular and then every once in a while fill the tank w/ premium to "help it" ( which is something I would do!). He said that is the worst thing to do, that once we start on regular, stick with it, the engine calibrates itsself to it, or something like that.

My question is 1) is that true that we don't need to use premium (even tho the owners manual has not been changed to state that regular is ok) and 2) is he correct about the consistency in the type of fuel used? thanks very much and p.s. we absolutely LOVE the power this car has. Had a Pacifica previous and it was a dog. ( but miss the interior space.)


  • wwestwwest Member Posts: 10,706
    With the advent of Mazda adopting the new wide band knock/ping sensors even the slightest level of knock/ping will be detected and the A/F mixture adjusted, and re-adjusted, accordingly.

    Regular fuel will simply result in slightly less HP, mostly at the "top" end.

    But your information from the "old man of the sea" is outdated. The latest engine/transaxle ECU firmware is designed to continously search for, and "re-learn" the optimal operational parameters, A/F mixture, timing, etc.
  • ratgirlratgirl Member Posts: 2
    Thanks so much for your quick response! Ok, so to put in simple terms, if I'm understanding you correctly, I am not harming the engine by using regular fuel. And also if I should use premium, the engine will "re-adjust" to the fuel. If so, should I use premium every now and then, or is that a waste of money......?
  • wwestwwest Member Posts: 10,706

    Your engine will provide more HP/torque with preminum fuel and less so with regular. If you romp on the throttle fairly often then I would use premium, if not...

    Basically MPG might be lower with regular but the payback, difference in price, may still make sense.
  • scordo17scordo17 Member Posts: 1
    Hi all-

    Wanted to get others opinions on this. Just bought an 07 with 20,000 miles. Love it so far. When we asked the salesman at the Mazda dealer about what fuel we would need to use, he said that some 07's have been adjusted after the fact so that 87 octane could be used. This sounds a little fishy to me. I know they did make updates to the 08s so that 87 could be used, but has anyone heard about changes or add-ons that are being made to 07s so you don't have to use 91+?

  • steverstever Guest Posts: 52,454
    I would think that if Mazda was making a change like that, they would issue a TSB about it.

    The Edmunds Maintenance Guide keeps track of TSBs.
  • wwestwwest Member Posts: 10,706
    The "key" to this seems to involve the use of the new(er) wide bandwidt non-resonant knock/ping sensors. If your CX-7 is so equipped then the engine/transaxle firmware can be written/updated to adjust the A/F mixture in accordance with octane rating.
  • 022540022540 Member Posts: 31
    I am taking my CX-7 in next week for 12,000 check up . I will try to find out about the fuel situation. When gas was over $4.00 per gallon we didnot drive the CX-7 except for long trips. I would fill one tank premium, next tank 89 octane. I was making over 25mpg on the interstate, non mountain areas. went from deep SW Louisiana to extreme northern AR.
    I also need to find out how many quarts of oil are needed with a oil filter and oil change. I cannot find it in the manual at all.

    I am going to try the Pennzoil Platinum full systhetic 5W 30 this time.
  • steverstever Guest Posts: 52,454
    You might get a better answer from Mazda USA than the dealer.

    The manual that I downloaded says that you use 6 US quarts of oil when you do both an oil and filter change. 5.6 quarts just for an oil change.

    How To Find Your Car Owner's Manual Online

    Hmm, Venice to Bull Shoals eh? (oh, SW LA - haven't spent much time around Lake Charles, went south of there on my last road trip).
  • fonefixerfonefixer Member Posts: 247
    Does anyone know if the 2009 model Cx-7 is engineered to use regular fuel?
  • wwestwwest Member Posts: 10,706
    Yes, the new CX-7 engine can safely be fueled with regular, but maybe with no out-of-packet savings.

    Should have been that way from the beginning.
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