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2008 Mazda 6 2.0 Diesel - Losing Power 1yr+, Engine & DPF Light & Rising oil - Mazda6FlashingDPF

Hello all, im a newbie to this site but have been reading a lot of relevent posts regarding the mazda 6.

I as the title suggests, have a 2008 Mazda 6 2.0 Diesel (Chassis JMZGH.....) and for the past year have been having increasing problems with the power of my car. For the first two years it worked fantastically, the fuel consumption was fantastic. But then one day I appeared to have a complete loss of power when trying to pull away. The revs dropped below what it is when idle, almost to a stall (flickering wildly above the 0rpm line) until I finally got a response, to which the car then flew forward. I thought it must have been my driving, and let it go to the back of my head.

But then it kept happening, and in the space of minutes continue driving well again. I noticed it was once initially after changing gear it would have no power, so id put my foot to the floor and it would jump forward suddenly when it finally started to respond. It was using up stupid amounts of fuel during one of these episodes. Mazda said they could not find a fault, and they also could not get it to fault on a test drive, checked the turbo as well as other things. I pleaded with the mechanic to do SOMETHING that might be it, as I was losing confidence driving the car, pulling away at junctions etc. He changed the fuel filter suggesting it MAY be dirty fuel.

Twice RAC were called out with loss of power, and both mechanics told me not to drive it, was a turbo problem. 1 felt the loss of power as he drove it, the towed it.

It went on and off and I took it back, and back again to find no fault and in the end I got so fed up of having to have it in the garage and having a hire car, I just got used to driving like that sometimes. I also repeatedly had my airbag light come on and off intermitantly, to which they replaced wires, modules, cleaned sensors and all sorts which has not FINALLY after a year stayed off for more than a few days.

Now after a year of being in and out of the garage I suffered not intermitant but constant loss of power. It was as if the turbo was not coming on at all. It was driving 0-60mph in 23 seconds, and was extremelly slow. It is also still guzzling up fuel. I phoned mazda to book it in the following week, but then on a drive home after 100mile round trip the engine light came on, the power loss was far worse (Im guessing limp home mode as I had to put it into 2nd gear to get up a hill on the motorway...) and further towards home the DPF light came on. I got my partner to look at the manual and he said it was ok to get home as long as it doesnt start flashing. Just as we approached our drive way, the DPF light started to flash.

They took it in and changed filters (not sure which ones) they also replaced wiring which was apparently causing the DPF & Engine light faults and gave me the car back. I went to drive it again, and the powerloss had not been resolved (again 0-60mph 23 seconds)

I left it a day or two thinking maybe the filters would take a while to work, only to find the engine light came on with the DPF Light came on immediatly and flashing, I had to drive another 100mile round trip that day so called the garage to let them know and book it in and also ask if it was ok to drive the 100mile round trip. To which the receptionist asked and replied, 'yes it should be fine, but if it shudders or losing power then your better not' When I explained it had been losing power for over a year she replied, oh well if it losing anymore then stop driving.

I drove the distance and it did start shuddering on the way home, luckily not far from home. I read on here about the problems with DPF and have just when to check the engine oil again to find its 3/4 way upto X. The last time we checked was the week before it went into mazda, but it doesnt say anything in the manual about checking the oil doesnt go upto X.

My car was made after the recalled ones, its chassis number is oneletter out at the beginning, but im still worrying since I drive my two young daughters in the car everyday and im petrified its going toblow up or rev out of control.

Mazda should have checked my oil level, so has it been normal at the garage and its now close to X in a week? Also, they are refusing to tow it unless I pay for it and im really worried about driving the car into the garage (around 8 miles from my home) so any advice would be appreciated....

Thanks for reading this far, and if u hadnt guessed, im a woman so dont know THAT much about cars so go easy ;)

2008 Mazda 6 2.0 Diesel - Losing Power 1yr+, Engine & DPF Light & Rising oil - Peter D

Read down the forum you are not the only one. The main thread has over 121 posts to can not miss it.

http://www.honestjohn.co.uk/forum/post/index.htm?t=77225

Regards Peter

Edited by Peter D on 22/01/2011 at 09:04

2008 Mazda 6 2.0 Diesel - Losing Power 1yr+, Engine & DPF Light & Rising oil - dieselnut

From reading others posts, these engines seem to have 2 main problems, leaking injector seals & a software problem with the DPF system, both of which result in unburnt diesel draining into the sump, diluting the engine oil & raising its level.

Some people seem to have success getting these problems fixed straight away by the Mazda dealer but others do not, which I think it must be down to the competence of the dealers workshop staff.

You say that the car has been back to the dealer many times & they havn't been able to resolve your problems, so doesn't sound like your dealers staff are very competent.

If the car is still under warranty I would take it to a different Mazda dealer, if not under warranty I would take to a diesel specialist who knows about this engine & its problems.

Your oil level is nearly at the X mark, once it goes past X there is a possibility of the engine oil getting pushed up back to the intake & causing an uncontrolled engine runaway that some unfortunate owners have had which can wreck the engine.

If you have to drive it to the garage I would keep revs as low as possible & keep speed below 40.

If you feel the car trying to accelerate without any throttle, brake it to a stop without touching the clutch so the engine wont destroy itself, then get it recovered.

You could also get a vacuum oil extractor ( £30-40 Ebay ) & drain some oil to bring the level back to the high mark which would be the safest option.

2008 Mazda 6 2.0 Diesel - Losing Power 1yr+, Engine & DPF Light & Rising oil - Mazda6FlashingDPF

Thanks so much for your informative reply, I have asked the garage to collect the car as I do not feel safe driving it.

Yesterday we had an incident of coming home, locking the car and in the morning had a text from our neighbour saying our passenger windows were down? My partner went to check, the car was locked and the windows were fully down. He opened the car and re-locked it and the alarm went off, because the windows were down. So how did the windows go down themselves?? Im totally miffed by it all. We havnt had the windows down since summer or something, unless for getting parking tickets...wth??

The car is still under warranty, has done 35000. I hope they do sort the problem, I am not allowing it to come back until they accept there is a problem. The treads on here have been printed off, so thank you to everyone who has made this problem public!

Thanks

2008 Mazda 6 2.0 Diesel - Losing Power 1yr+, Engine & DPF Light & Rising oil - Mazda6FlashingDPF

I have just found the paper work, and they did and oil & filter change on the car the week before I checked and found it 3/4 to X. Its now almost touching X. Is it possible for the engine to cause this? or has it been over filled? Sorry for the dumb questions!

2008 Mazda 6 2.0 Diesel - Losing Power 1yr+, Engine & DPF Light & Rising oil - dieselnut

It's certainly not a dumb question.

It's possible that the oil was overfilled, but the fact that you have seen the oil level rise from 3/4 to X in a couple of days suggests otherwise.

The DPF system uses the engines fuel injectors to keep itself clean.

When the cars ECU detects the DPF is getting clogged up with soot it instructs the injectors to inject extra fuel. The fuel is injected at times in the engines firing cycle when it will produce heat rather than power. The heat raises the temperature of the DPF & burns out the soot, it takes just a few minutes & probably wont even be noticed by the driver.

If too much fuel is injected than can be burnt, this excess fuel will run down the cylinder wall into the sump, mix with the engine oil & raise its level.

If the engine oil is hot enough ( above about 70 C ) the diesel in the oil will start to evaporate & will be passed back to the engine via the breather system & be burnt. But if you do a lot of short journeys ( less than 10 miles ) & the oil doesn't get to 70 C & vaporise the diesel, the oil level will continue to rise

I would have expected that the system would have been designed so as not to allow so much fuel to be injected as to run down the cylinder walls & Mazda seem to be the only manufacturer that suffers with this problem in such a major way.

I hope the above explanation gives you more of an idea of what is the cause of your problem. I suspect there will be a faulty sensor somewhere that is causing the system to regenerate the DPF too often.

At least you have managed to catch the problem before blowing the engine which has befallen some other owners, Mazda should be ashamed of themselves.

Hope the dealer is able to sort it for you quickly.

2008 Mazda 6 2.0 Diesel - Losing Power 1yr+, Engine & DPF Light & Rising oil - Med

what happens if the ECU fails?

2008 Mazda 6 2.0 Diesel - Losing Power 1yr+, Engine & DPF Light & Rising oil - unthrottled
The engine won't run-the injection is electronically controlled. Just to add to the DPF issue-it is quite true that Mazda have had more than their fair share of fuel in oil problems Bu the post injection strategy that causes these problems can be mitigated by operating style. Many people have commented that 'driving thar car hard for 10 miles' will regenerate the particulate trap. This is entirely right. The problem is that driving at a constant -say 30mph only uses about 5-6 hp. At this load, the exhaust gas temperature is only about 200C, way below the ~600C required for soot particulate burn off. The ECU has to inject a lot of fuel to raise the temperature of the exhaust gas to 600C. Driven hard, the exhaust gas temperature is naturally much higher, so less fuel needs to be injected into the exhaust stream. God excuse for some fun too!
2008 Mazda 6 2.0 Diesel - Losing Power 1yr+, Engine & DPF Light & Rising oil - Med

hi unthrottled,

thanks for your prompt response...i love forums! :)

ok, what about a faulty dpf sensor? if the sensor does not work and the ecu is working as it should be somehow in such respect it keeps giving the injector the command because the dpf sensor is not telling it otherwise (whether it full of soot or not) then raw diesel will keep getting injected into the dpf system, or leaks down the cylinder injector....into the sump?

Wouldnt this cause a large dilution issue? whereas the driver wouldnt know that the dpf needs a regen or not because no dpf warning light would appear......

2008 Mazda 6 2.0 Diesel - Losing Power 1yr+, Engine & DPF Light & Rising oil - unthrottled
The dpf sensor measures temperature as well as the pressure differential across the trap. If the exhaust gases are hot enough, passive generation occurs and additional fuel injection is not required. The sensors themselves are fairly reliable. Faults usually lie upstream. Most marques use a similar system, and all suffer from oil dilution during active generation. Diesels really don't like short journeys or extended idling. DPF problems are much reduced when the engine is used for the duty cycle the designer intended.
2008 Mazda 6 2.0 Diesel - Losing Power 1yr+, Engine & DPF Light & Rising oil - Med

*deleted - sorry double posted

Edited by Med on 26/01/2011 at 21:21

2008 Mazda 6 2.0 Diesel - Losing Power 1yr+, Engine & DPF Light & Rising oil - pat22090

The windows will all open if the open button on the keyfob is pressed for > 5 seconds. (I know because it happened to me when I fell asleep on my keys) Same thig on Fords as well!