CX-7 acceleration issue - lost for causes

tron2005

Member
:
Mazda CX7 Sports 2.3 Turbo
I have a 2007 2.3 petrol turbo CX-7 that I have noticed over the past couple months to cough and splutter if I put my foot down and bog down with NO acceleration if I keep my foot down.

Usually the car will take off from a standing start fairly well, but if I need power to accelerate / pass slower traffic, etc, then forget it and it's rather quite dangerous so I don't attempt to pass slower traffic now.


I initially thought it may be a dirty / clogged fuel filter with the car starving for fuel as it needed more to accelerate, so I changed the fuel filter.

Changing the in-tank fuel filter is another story AND I'll add another post about that.

The filter was extremely dirty, possibly never been changed at all.

The car has 105km on the clock.


This made no difference to the cars accelerating performance.


I guess I really do need to take the car to a good tuner and have his scanner read thru the ECU messages.

It could be an issue with O2 sensor although I am NOT getting any engine warning lights.


So basically just wondering if anyone else has had problems with their CX-7 coughing and spluttering and simply NOT accelerating at all when the right foot goes down??
 

lildisco

Member
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08 CX7 AWD GT w/Nav, 06 6i Sports Sedan
Are you using the recommended fuel? What about the egr system? When is the last time you cleaned the egr system? Not sure if you have seafoam where you're at, but that's a start. Do you have a check engine light? Warning indicators?

Sent from my XT1254 using Tapatalk
 

tron2005

Member
:
Mazda CX7 Sports 2.3 Turbo
Are you using the recommended fuel? What about the egr system? When is the last time you cleaned the egr system? Not sure if you have seafoam where you're at, but that's a start. Do you have a check engine light? Warning indicators?

Sent from my XT1254 using Tapatalk

Yes I am using better than the recommended fuel (using 98 octane rating).

I was looking at the EGR but was thinking it's not giving me the same symptom as a dirty EGR, for example I am NOT getting any erratic idling or hard starting which is common for dirty EGR's.
But I will check / clean EGR in any case.

Would prefer not to use Seafoam but simply remove and clean EGR.

As stated - NO engine warning MIL (Malfunction Indicator light.)
 

AaKoV

Member
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Mazda CX-7 2007
Hi tron2005,
I have a same issue with my 2007 cx-7. Dis you get to the bottom of yours? Just wanted to ask to share yiur knowledge and experience. I have done lots of work on my cx-7 and still have the same issue! This is very frustrating! Please share a few words of what the outcome was in yiur situation. Greatly appreciate it!
 

kcbhiw

What "Lifestyle"?
Contributor
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64 Valves, 16 Cylinders, 7.2L, 622 HP
Check your spark plugs and turbocharger operation. I just purchased a CX7 that ran poorly. I discovered the plugs were fowled due to high oil consumption due to a failed turbo. Once the plugs were replaced, the car ran much better but was very low on power as the turbo was seized.
 
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CX7 2007 Sports
Hmmm, any check engine light? (If so, can you post the code, that would help steer you in the right direction). The Turbo kicks in at ~2500rpm. Does it run perfectly below that?

My hunch: I'd do a compression test to determine whether this is a cylinder issue or not (you can Youtube it, basically you put a pressure gauge instead of your spark plug, one cylinder at the time. There is also an awesome Youtube on how to remove the Intercooler to get to the spark plugs: that one is this link https://www.youtube.com/watch?v=x4y9Ofxp-rM).

Where I'm going with this is that this sounds a lot like cylinder misfiring when your Turbo kicks in (or if lucky, it's just your turbo... check for leaks), which is very possibly due to the same problem I just had = blown fuel injector seal. These seals are a piece of #### and they will need replacement one day or another. That said, it would be very surprising to see that happen without check engine light/codes.
 
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Seattle Wa
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73 FLH
I can't count the number of times I've heard "There are two kinds of CX7 (K04-xx) turbo, those that have failed and those that will".

Warning: Short attention spans go to the end...

Disclaimer: I don't own or work on any CX7-T. I just see the turbocharger. I use them for a far different purpose.

What I see most often is coked up oil inlet and outlet. Simply no oil flow through the turbo. I've seen the install and heard the rant from usually reliable mechanics. So the most usual cause of death is "arterial blockage". :)

The symptom is easy enough to diagnose. Expose the turbo compressor inlet and finger the compressor wheel/shaft. No play and rotates easily, probably good. Wobbles all over the place, probably bad.

The second most common issue I see is a crack between the waste gate seat and turbine outlet. This can evolve into a "cut" waste gate valve seat/valve, and noticeable loss of power. The twin turbo rotor motor was famous for this trick.

Okay, now for the TLDR crowd, put a boost / vacuum gauge on the beastie. No boost, no power. If boost and it's still lagging you have a different problem.

P.S. If your turbo is junk, I want it. :)