Big problem with my CX7. Spark plug Fouled. Help

[CX7 Driver]

When the temperature out side is less than 32 F then the car is very hard to drive. It will not accelerate, and it is bug down. I went to the dealer four times already and all they do is clean the plugs an tell me to drive longer distance. My wife drives the car every morning to work for about one and a half hours. So what can I do? Is it maybe that the car is running to rich? So is the ECU bad?

[mikey1981]

1. use the search tool for the forum, its great for finding related answers located on the top tool bar, and
2. the car hates cold weather, I dont think there is something necessarily wrong with your particular vehicle, its just once it goes under freezing, the mazda doesnt like it much.

By the way, have they told you how they clean the plugs? you can probably save a trip to the dealer and do it yourself. Hold the accelerator down while in park and keep it around 4k rpms, when the rpms drop, it means, that in the computers eyes, it has cleaned the "plugs" - thats what my dealer had told me. it cycles the carbon out of the engine.

hope that helps.

[SuperStretch18]

In cold weather, the denser air makes the engine run lean, triggering a fuel cut situation. Do a search for "fuel cut" and you will come up with a ton of threads from the MS3 & MS6 guys on how they are addressing this. Not sure how you feel about modding, but there options available. If not, then a trip to the dealer might be in order. Not sure if they have any tricks, but it is something that they should be aware about on all of the DISI vehicles...

[CX7 Driver]

Thanks for helping me. The dealer takes the plugs out and cleans them. So for me to take them out is hard especially in the cold weather. Is there a hotter burning spark plugs available for it?

[erhayes]

I would hope you are using a top tier fuel or at minimum a name brand fuel of 91 or higher octane. Off brand gas does not have the additive packages that keep the valves and combustion chamber clean. Something doesn't sound right if your drives are that long and your constantly getting spark plug fouling. I suspect poor fuel as the most probable cause. People in Alaska drive CX7s so the cold you experience is mild in comparison. Maybe a good experienced mechanic will chime in here. Ed

[UpNorth]

I suspect poor fuel as the most probable cause. People in Alaska drive CX7s so the cold you experience is mild in comparison.

I'll take the Alaska cue.

I'm using Chevron's 90 octane (the highest we can get here). Most of my drives are short and I have cold weather much of the year. With that, my CX-7 is still fun to drive and responsive. I do warm up the car and suffer especially crummy mileage in the winter, but I think that your problem goes beyond the mercury dropping below 32. (Though now I want to do a search on fuel cut too.)

Good luck.

[StickShiftCamry]

Never heard cold being a problem, same response in 100 F and 12 F. These are isolated problems people are having, the car doesn't "hate" the cold, its a new car and it drives like a new car, which means perfect except for factory programmed delayed electronic throttle.

[erhayes]

I seem to remember something about a valve in the intake manifold system that causes cold weather issues. Check for TSBs as one was put out about the valve. I can't believe a dealer would have overlooked this possibility though. If I remember the TSB or can find it I will report back. Ed

[erhayes]

CX7 Driver. The service Bulletin you need to find to address your problem is 01-010/07 which was last issued on 7/13/2007. The Bulletin refers to a "variable Swirl Valve" that sticks in cold weather. Keep me/us informed when the issue is resolved. Ed

[CX7 Driver]

thank you all .
This morning had the same problem. Rev the engine to 3000 rpm for about a minuets and the rpm went up to 4000 rpm and after that the car was ok. I kind used what mikey1981 recommended to clear up carbon. I think It still a issue with carbon buildup on the spark plugs. I all ways use good gas 94 bp.
The mechanic at the dealer did ask me if i use the car on short trips, but I don't, even if I did then I can't believe that Mazda would build a car that can not be used on short trips.

[justanothermp5]

do u use premium gas? if not maybe tahts the problem with the sluggish feeling

[erhayes]

You should not need to rev the engine frequently to get it to run smoothly. I really think you may have a sticking variable swirl valve. I gave you the TSB number which also describes poor cold running issues such as you are experiencing. You are correct that Mazda would not build a car with that kind of problem. Get the dealer to fix it correctly and just cleaning the spark plugs is not fixing it. Ed

[CX7 Driver]

Thanks erhayes for the service bulletin. I will go to the dealer next week just printed it out today.

[Mazda3]

The problem is the O2 sensor. Mazda Canada has finally traced the power loss problem to faulty O2 sensors. There hasn't been an official TSB released yet, but the local dealer is replacing the O2 sensor on anyone experiencing these type of problems on the DISI motors. It was a hard problem to diagnose because the problem usually only occurs periodically in some vehicles and for some reason never throws a code or triggers the check engine light. It now seems that 75% of the issues with the way the CX-7 runs can be traced back to this sensor. Have your dealer call the techline. If the US techline doesn't know about this then have them call the the Canadian techline.

[erhayes]

So now you have two good posibilities to have the dealer check on. Maybe Mazda3 will give you the phone # and name of the service technician who understands the O2 problem.

[Rick's CX-7]

By the way, have they told you how they clean the plugs? you can probably save a trip to the dealer and do it yourself. Hold the accelerator down while in park and keep it around 4k rpms, when the rpms drop, it means, that in the computers eyes, it has cleaned the "plugs" - thats what my dealer had told me. it cycles the carbon out of the engine.

hope that helps.

How does holding the RPMs at 4k until they drop clean out carbon from the spark plugs? I mean, how does this actually happen?

[CX7 Driver]

My understanding is that the spark plugs will reach their optimum temp. and the carbon build up will burn off.

[Rick's CX-7]

I did this today and it worked just as you guys said. I held 4k RPMs for about 1-2 mins and after that, the speed went down to idle despite my foot being on the gas. Once I let go and stepped on it again, it was back to normal. Did it work....did it clean out the carbon? Who knows!

Rick

[CX7 Driver]

Finely had enough and called Mazda USA costumer service. Talk to a guy that took a report, once the dealer that did all the service calls them back he will see what he can do for me. Will let you guys know what they say when they call me back.

[mikey1981]

I did this today and it worked just as you guys said. I held 4k RPMs for about 1-2 mins and after that, the speed went down to idle despite my foot being on the gas. Once I let go and stepped on it again, it was back to normal. Did it work....did it clean out the carbon? Who knows!

Rick

;) . i think the only reason the tech even told me that procedure was because they were sick of seeing my cx-7 every day. if it works, who really knows....could never tell on mine because i had a zillion other probs.

[mikey1981]

my reference to "hating the cold" was the time it takes the 7 to spit actual heat, reaching temp, the shutter valve problem caused/triggered by colder temps, and the shakes the car gets in the steering column while warming up (some of you may not have the last one)

[erhayes]

Hoping CX7 driver will come back with good news. If his dealer does not fix it correctly then try another dealer by contacting the Mazda district representative/customer service. Ed

[mikey1981]

yea i hope so too

[CX7 Driver]

Finlay Mazda got back to me, and it is the same old thing they suggested that I go to a different dealer to service my car. (cricket) That will be my next move. But now that the temperatures are getting warmer the problem is going away. I'm just worried that next winter it will be back.

[chris41]

I have a similar issue.....

My wife's 07 (April) CX-7 drives like a sport's car......very peppy and quick. She had a few hundred miles on the odometer when she bought it last month (probably a demo or salesman driver).

My BRAND new 08 CX-7 seems a little sluggish. I did the sparkplug cleaner procedure and we both use the same Sunoco 94 gas. I just rolled over 1k on the odometer. Her car is so much more fun to drive!

I'm wondering if the difference isn't the engine programming, but perhaps the transmission? What bothers me is you'd think the 08 would have the most current programming. The TSB's that pertain to my situation are for early build 07's.

[Mazda3]

I have a similar issue.....

My wife's 07 (April) CX-7 drives like a sport's car......very peppy and quick. She had a few hundred miles on the odometer when she bought it last month (probably a demo or salesman driver).

My BRAND new 08 CX-7 seems a little sluggish. I did the sparkplug cleaner procedure and we both use the same Sunoco 94 gas. I just rolled over 1k on the odometer. Her car is so much more fun to drive!

I'm wondering if the difference isn't the engine programming, but perhaps the transmission? What bothers me is you'd think the 08 would have the most current programming. The TSB's that pertain to my situation are for early build 07's.

The latest round of updates was released after 08 production started, they might still apply. Worth checking anyway.

[Zhos]

HI, folks. I've read this thread earlier, when I was trying to figure out what was wrong with cold weather driving on my car, but could not get the dealer to do anything until recently.

Mazda has finally issued the TSB for the O2 sensor. I went to my dealer and based on my history of complaints and their tests they have replaced the sensor in my car. Results - well, drives much better, but what is more interesting, the MPG went up from approximately 17-18 (70% hwy 30% city mix) to about 20 (still testing, only used 1 tank so far).

[erhayes]

I guess progress not perfection is the byword. Hopefully the cold weather problem is gone.

[techspeak]

i find the ECU doesnt make use of higher than 91 octane fuel, as well high octane and cold weather seem a problematic combo in stock. The combination of the ECU overcompenation, cold weather, high octane and direct injection = one 'chilly' combustion chamber and poor fuel burn

[Rick's CX-7]

i find the ECU doesnt make use of higher than 91 octane fuel, as well high octane and cold weather seem a problematic combo in stock. The combination of the ECU overcompenation, cold weather, high octane and direct injection = one 'chilly' combustion chamber and poor fuel burn

I saw better mileage on 87-89 in the winter than with 93. I saw better performance with 93 during the hotter months. I agree with your statements.

Rick

[2.3turbo]

i find the ECU doesnt make use of higher than 91 octane fuel, as well high octane and cold weather seem a problematic combo in stock. The combination of the ECU overcompenation, cold weather, high octane and direct injection = one 'chilly' combustion chamber and poor fuel burn


The ecu will only advance timing to a certain point. Higher octane won't change the advancement or temperature of combustion. Infact, atleast where I am, the highest octane available is brewed with methonal and burns hotter because it burns leaner.

Since I have just rolled over the 1000kms range on the cx, I haven't really learned much about it but most turbo engines have a knock sensor that will pull timing out of an engine as a safety measure when pinging or detonating (engine knock) is detected. That could explain the problem. If you do have dirty plugs and you are not getting a hot enough spark to ignite your combustion chamber every rotation then your timing and power are being held back. Just a thought, not that it helps.

I would also say that if it was heat that disolved the carbon, running the car under load with boost is going to significantly increase exhaust gas temperatures (by probably 400 degrees)and burn your carbon more effectively. So I don't see how running your car at 4000 rpm for a minute or so in park does anything other than waste gas. Do these cars use an iridium plug or what?

[TRXSandRacer02]

these are direct injected engines, never mind all that. You need to turn key to on, put pedal to floor to put the pcm to clear flood mode, crank it for 15 seconds, 2 times in a row, turn key off, turn key on and crank normal and when it hits hold the rpms at about 2000 to 2500 rpms to clean the plugs. If your o2 sensors read fine there is no need to replace them. The tech who recomended an o2 sensor shoudl abviously know that when cold, they dont even read because it is in open loop which means pre calibrated pcm tables. The plugs are iridium and last 100k. Email for any questions or replies but lets use common sense, i direct injected engine that is trubo charged, needs at least 91 octane(new disi engines only require 89) you ahve to run it for at least 10 minutes because a turbo disi engine or any engine for that reason runs so rich at codl start up of course its gonna load up. The hyrdocrabon(ie fuel) at the tailpipe at cold start are so high its nor even funny

[CX7 Driver]

Well new winter is here in Chicago and we had temp at -4F to my amazement the car performs perfectly. So I don't know what changed but I drive the car the same way.

[TRXSandRacer02]

If everyone can look up tsbs for other stuff why cant you all look up the tsb for pdi step 3 delivery where it says to decarbonize the spark lugs by running the engine at 4000 rpm for 3 minutes. It is for all turbo 2.3s and rx8s to prevent flooding and fouled plugs. If you ever owned an old v8 engine from the 70 or 80 that was carbureted, you would know that that is the easiest way to get your plugs clean is to hold high rpms or do highway driving

[techspeak]

Well new winter is here in Chicago and we had temp at -4F to my amazement the car performs perfectly. So I don't know what changed but I drive the car the same way.

my guess is that it finally broke in :p

[CX7 Driver]

Finlay found the problem all 4 coils were bad. Which is unusual but I guess not impossible.