2016 CX-9 Loss of Power

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No reports of carbon on the backs of the intake valves. In any case, that wouldn't be the same as seplant is reporting.

Carbon on the backs of the intake valves is a result of the engine's crankcase breather system not adequately removing oil vapors before venting to the intake, plus direct fuel injection where no gasoline is in the intake air to wash off these valves. I think most engine makers have corrected this problem.


I have to disagree somewhat. Ford, Volkswagen, Audi, BMW and GM's Cadillac division are still dealing with this issue, though aggregate reporting of these problems has fallen over the years since mass production of DI engines hit the market. By my evaluation - it is still a problem. However, manufacturers have had to deal with emissions regulations that kept coming over the years and this has been part of the price of admission. Toyota, Honda and Acura as far as "mass producers" go have done a better job, but that could very well be because they came late to the party, sat back and went to school on all those problems everyone else initially had.

Ford, has probably been the poster child for DI carbon problems, however.
 
Well, we had a happy ending. The engineers couldn't figure out the problem with our CX-9, so Mazda offered to buy back our vehicle and replace it with a new one. They gave us top dollar to trade my 2016 CX-9 (with 20,000 miles and engine issues) plus they gave me a boatload of incentives. We just picked up our brand new 2017 CX-9. Mazda did us right!


Wow! I just now read this far. They offered you top dollar and a new 2017. That was a class act, indeed. Kudos to Mazda Corporate for doing that, no doubt - and great for you! Congratulations!

However, I'm now more perplexed than I was before I wrote my initial reply. I now have even more questions given my history with GM and a C5 Corvette that lost significant power above 4,300 RPM both on the road under actual loads and on the dyno. GM never offered to buy back anything by the way and they never were able to solve the problem. I guess that just shows the difference between the two companies.

Still, I'm left wondering now whether or not this anomaly will only show up in 2016 production lines of the CX-9 and if so, which drive train (Front Wheel only, AWD or both). If I'm guessing right about Mazda's integrity, they are probably now using your old 2016 as a research vehicle. I'm pretty sure you are happy with your new 2017, but I would sure like to know if this problem extends down the production time line and into any of the 2017s. I'm sure new 2018 owners and prospective owners want to know the same - as this was one of the first very serious issues that I've read about on the CX-9. Power loss that severe without a fix from the OEM is by definition a very serious issue.

Anomalous lemons are going to statistically occur with any automobile manufacturer no matter who that manufacturer happens to be or what they make. It is the nature of the mass production. However, I would like to know if this was merely anomaly, or some kind of manufacturing flaw that only shows up under certain manufacturing conditions. It is obviously not a design flaw, else I would expect the number of reported instances to be significantly higher. I just want to know that it was not a lingering production error onsite that apparently got missed and then trickled into 2017s and 2018s.

I wish there was a way to track what Mazda is actually learning from your 2016 CX-9.
 
I wish there was a way to track what Mazda is actually learning from your 2016 CX-9.

Our dealer let us know that Mazda had them replace the entire fuel injection system on our old 2016 CX-9. They won't know for sure if that fixed the issue until someone drives the vehicle for a while.
 
Our dealer let us know that Mazda had them replace the entire fuel injection system on our old 2016 CX-9. They won't know for sure if that fixed the issue until someone drives the vehicle for a while.

Very interesting an very ironic because that's exactly what GM did with my Corvette when it suffered a loss of power above 4,300 RPM with no apparent reason. The replaced all fuel injectors (including fuel rail system, etc.), the piezo transducer knock sensor, spark plugs and wires to no positive effect. Of course, the mass air flow sensor, ECM and PCM were next, followed by the entire fuel sending unit (FSU), etc., etc., etc. They never found the culprit and thus never solved the problem - nor did they ever suggest a buy back. They were always attempting to replace something, no matter how irrelevant, in order to show a paper trail of corrective actions being made. GM won't buy back when their Regional Manager concludes that more can be done to rectify the problem.

I still love the Corvette. I just wont ever buy one again given the way GM raked me over the coals about a material defect they could not resolve. I'm glad Mazda demonstrated some integrity and solved your problem with an offer.
 
I had a very similar problem a couple of months ago..


Turns out they (Dealer, Mazda Regional, Mazda USA AND Mazda Japan) have absolutely no idea what caused it, so they replaced the
knock sensor and the ENTIRE EXHAUST MANIFOLD. Pretty crazy.

I'd like to note that Mazda had to hire translators to get the Japanese engineers on the phone with the local dealer techs.

The car was in the dealer for over two weeks. I have it back now and it's running flawlessly, but I'm not convinced they solved the actual problem.

PM me if I can be of any help.


Routine and common Parts Swapping when the Dealer, Regional Manager and Corporate Office has no clue about the Causation. If you do the homework, you will see that this is the case with just about any mass produced auto manufacturer when it comes to the issue of reported "Power Loss Under Throttle."
 
I had a very similar problem a couple of months ago..


Turns out they (Dealer, Mazda Regional, Mazda USA AND Mazda Japan) have absolutely no idea what caused it, so they replaced the knock sensor and the ENTIRE EXHAUST MANIFOLD. Pretty crazy.

I'd like to note that Mazda had to hire translators to get the Japanese engineers on the phone with the local dealer techs.

The car was in the dealer for over two weeks. I have it back now and it's running flawlessly, but I'm not convinced they solved the actual problem.

PM me if I can be of any help.

I have read carefully what you have written and I had the same failure with my 2017 mazda cx9. turns out there is a barometric sensor that works with the engine. I went to the dealer after having this massive failure and seems the barometric sensor had failed and the car thought was 2000 meters under water , that made everything to fail.
at the moment that this happened I stopped the car turned it off wait for a minute and restarted. everything went back to normal but seems the whole computer has to be changed.
regards
M
 
I have read carefully what you have written and I had the same failure with my 2017 mazda cx9. turns out there is a barometric sensor that works with the engine. I went to the dealer after having this massive failure and seems the barometric sensor had failed and the car thought was 2000 meters under water , that made everything to fail.
at the moment that this happened I stopped the car turned it off wait for a minute and restarted. everything went back to normal but seems the whole computer has to be changed.
regards
M



I can't imagine this not throwing a DTC with a Check Engine Light. Did you check for DTCs or did you notice any Warning /!\ under Mazda Connect > Applications > Vehicle Status Monitor before you took the CX-9 to the dealer?

Did they specifically tell you that the problem was with the MAP Sensor (Manifold Absolute Pressure Sensor)? Or, did you hear them say Mass Airflow Sensor?

Ultimately, it is the ECU that determines how much fuel is delivered and thus how much power is made. You say the original symptom was a distinct "power loss." That implies on acceleration the engine simply failed to produce normal power for a specific throttle setting (in general terms). When you step on the accelerator pedal you also change the barometric pressure inside the MAP sensor.

Naturally, the vacuum from the intake manifold puts negative pressure on the MAP and the flexible silicone based chip/diaphragm inside it will report to the ECU a specific level of converted voltage. The ECU takes that signal along with other inputs and then determines fuel delivery. So, if there is a voltage irregularity within this part of the MAP, when you step on the accelerator pedal the ECM may be receiving incorrect signal and that could lead to incorrect fuel delivery causing "power loss" as you describe. The MAP also plays a role on some boosted engines with a turbo charger as the CX-9.

Or, the MAP could be just fine and the ECM/ECU could be the problem in this one regard - which would most like require replacing the entire unit. The other variable inputs to the ECM/ECU for fuel deliver are Air Temperature and Engine Speed - both of which have their own sensors that should be checked for a full diagnostic run. If there is a faulty Higher Temperature input, the ECU/ECM will dump less fuel and that too could cause your "power loss." If a faulty Low Engine Speed is being sent, then again, less fuel will be injected and thus less power made.

The MAP might be one of the easier fixes on this engine. But, I am surprised that no DTC was thrown and that the Mechanic made no mention of an OBDII code which probably would have been one of the first things they checked.

You say the "whole computer has to be changed." That sounds like they are removing and replacing the ECU/ECM and if that is the case, my question would be a resounding why. I could see a faulty MAP sensor. I would have a harder time reconciling a faulty ECU/ECM this early in the life of the vehicle. Possible? Yes, sure it happens. But, I would not like to hear that they had to replace such a mission critical unit this soon.

Can you please report back what specific part they actually replaced once the repairs are made. Thank you.
 
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Thanks for posting this. I'm having the same issue with my 2016 Mazda CX-9 Signature with 34000 miles. It seems like the turbo is not kicking in after driving it in hot weather. I'm getting a bit worried as I'm coming up on the warranty end. I called the dealer and they said they haven't heard of this. I'm going to take it in.
 
Thanks for posting this. I'm having the same issue with my 2016 Mazda CX-9 Signature with 34000 miles. It seems like the turbo is not kicking in after driving it in hot weather. I'm getting a bit worried as I'm coming up on the warranty end. I called the dealer and they said they haven't heard of this. I'm going to take it in.

Have your dealer contact the service department at O'Daniel Mazda in Fort Wayne, Indiana. Ask for Tim. He should know all about it.
 
Thanks seplant. Update on my car: It was the low pressure fuel pump, which they replaced and now it seems to be fine again. However I'm quite concerned that the fuel pump on the new series CX-9 died after only 34000 miles. This one was covered under warranty - but the next one will likely not. The fuel pump on our previous Honda Odyssey never died while we had it for 10 years and 140000 miles.
 
Thanks seplant. Update on my car: It was the low pressure fuel pump, which they replaced and now it seems to be fine again. However I'm quite concerned that the fuel pump on the new series CX-9 died after only 34000 miles. This one was covered under warranty - but the next one will likely not. The fuel pump on our previous Honda Odyssey never died while we had it for 10 years and 140000 miles.

Good to hear they were able to fix your issue. Since they gave me such a killer deal on a replacement CX-9, I went a head and purchased a 100,000 mile warranty, so hopefully if this issue pops up for me on this vehicle, it'll be covered.
 
That's in interesting idea seplant. Can I ask about how much such a warranty costs? And what's the deductible each time you bring it in? Thanks.
 
That's in interesting idea seplant. Can I ask about how much such a warranty costs? And what's the deductible each time you bring it in? Thanks.

We ended up paying just under $2,000 for a 5-year, 100,000-mile, bumper to bumper, no deductible, fully transferable warranty at the time we purchased the vehicle. I'm sure people here will say they could get a better deal, but after what we went through with our first CX-9, we thought this was worth it in case we experienced the same kind of issue again after the original warranty expires. I'm not sure what is available for vehicles such as yours with 34,000 miles on it.
 
Unfortunately the Exhaust Manifold Gate in 2.5T becomes defective with age....needs replacing.
This is why engine lacks power.

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Unfortunately the Exhaust Manifold Gate in 2.5T becomes defective with age....needs replacing.
This is why engine lacks power.

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Yeah, one guy has posted that on a RX-8 forum and nobody else on any other board has done so. The issue here was a faulty fuel pump.
 
Yeah, one guy has posted that on a RX-8 forum and nobody else on any other board has done so. The issue here was a faulty fuel pump.

Yep, those pictures have nothing to do with the loss of power reported in the original post.

For posterity's sake, here is where the pictures came from. The TSB states that the cracks do not affect performance or cause noise.
 
Time AFTER that original 'issue' Mazda NAO Bulletin, Mazda said the manifold 'cracks' do not have concern for performance and not to replace said parts with new ones.
 
Time AFTER that original 'issue' Mazda NAO Bulletin, Mazda said the manifold 'cracks' do not have concern for performance and not to replace said parts with new ones.

Sorry not sure what you're trying to say here.

The pictures you posted were screencaptured from the same TSB linked above (dotted lines are the exact same). Regardless of timing, the point is that they have nothing to do with the power loss mentioned in this thread, and in fact have no impact on power or noise period.
 
Sorry not sure what you're trying to say here.

The pictures you posted were screencaptured from the same TSB linked above (dotted lines are the exact same). Regardless of timing, the point is that they have nothing to do with the power loss mentioned in this thread, and in fact have no impact on power or noise period.

@AdzamOZ got your message, I understand now. To clarify for any future readers, AdzamOZ posted those pictures from an internal Mazda service alert, before the TSB was created. At that point in time, the cracks had just been discovered, and nobody knew if they might have affected performance.

Some time after, the service alert became a TSB, which explains why the images are identical. Apologies for the confusion, @AdzamOZ.


With that said, it appears that the original issue has been traced back to the fuel pump, and has now been resolved. Thread closed.
 
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