Mazda CX-7 (2007 - ) - Engine emission at low revs

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Sat 23 Jan 2010 16:30
Engine emission at low revs - mc625
Hi there,

Have noticed over the last month that when driving at low speed and revs I am getting what to me appears excessive emissions. Have had for just under 1 year and got about 14k on the clock.

Have taken the car into the dealer who have stated that this is normal and is just condensation, although they did say that the oil levels were high so have taken it back to the garage that serviced the car to rectify. The thing that concerns me is that I see nothing similar with other cars on the road.

Have read the discussion thread on Mazda 6 DPF filter problems and am concerned that this could be something similar although it is a petrol DISI engine.

Anybody have any thoughts?
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Sat 23 Jan 2010 21:55
Engine emission at low revs - Lygonos
If you can see anything out the back it's condensation or your engine is truly knackered.

My money is on condensation!

If the ambient temperature is cold, then the water vapour in the hot exhaust gases condenses rapidly as it exits the tailpipes.
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Sat 23 Jan 2010 22:17
Engine emission at low revs - SteelSpark
I have noticed exactly the same thing on my 09 reg 2.0 Diesel Mondeo a couple of times over the past couple of weeks.

On both occasions I have been moving off from a standing start (once at lights and once at a toll bridge), have set off in 1st gear, revved the engine a bit and happened to look in my rear view mirror at the same time, to see a big cloud of what appears to be water vapour, rather than smoke.

It was starting to concern me because I also have not noticed such a large amount of emission from other cars on the road, including cars moving off in front of me.

Part of me wondered whether there was something wrong with the car, and the other part wondered whether there was something wrong with the way that I was moving off quickly from a complete stop.

On both ocassions the outside temperature has been low (likely below or just above freezing) and the engine was hot (having driven at least a couple of dozen miles before noticing it), but the cloud definitely looks like water vapour, although it is big, and dense enough to completely obscure the car behind me for a second or so.

Edited by SteelSpark on 23/01/2010 at 22:18

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Wed 27 Jan 2010 23:28
Engine emission at low revs - mc625
Thanks for the replies,

Have taken it into a non Mazda garage today who have said that they do not think the smoke coming from the exhaust is condensation.

They did say that the oil level was on the minimum which indicates it may be burning oil as it was only serviced 1500 miles ago!

Looks like another trip to Mazda to see what they say.
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Thu 28 Jan 2010 00:30
Engine emission at low revs - Lygonos
If the 'smoke' is burnt engine oil it will have a sickly/savoury smell and will usually have a bluish tinge.

If you see it when the engine is fully warmed up and generally after sitting at idle for a while then pulling away it may be oil bypassing the valve stems and getting into the cylinders.

Could it be a turbo failure? Smoke is often the first sign of a blown seal.

www.mazdaspeedforums.org/forum/f10/mazdaspeed-2-3l.../

Most of these US engine failures on the same engine are 'ka-boom' style, and often on modified engines running increased boost.

Should be easy enough to shove the emissions probe up it's bottom and see the hydrocarbons off the scale of the smoke is oil-based rather than water.
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Thu 28 Jan 2010 11:27
Engine emission at low revs - SteveLee
If the car is normally driven very gently it'll be condensation.
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Mon 7 Jun 2010 17:55
Engine emission at low revs - mc625

All thanks for your replies.

Not beena ble to get on the site for some time becasue of computer / internet issues.

The car has been back to Mazda for the 18,000 mile service with smoking issue still as bad. Apparently Mazda have put something out to their dealers when reporting problems with smoke emissions, this is obviously a known problem!

Step 1 - compression test.

Step 2 - put 5W 40 oil in, usual oil is 10W 40.

Step 3 - replace turbo.

Steps 1 all OK and holding 12 bar, 5W40 oil has been put in, emissions have got better but still noticable if idling at low revs for more than 1.30 - 2 minutes. Step 3 still to be done as Mazda are saying that work is not covered by warranty, car is only 15 months old!

Have also noticed in last couple of days a slight whirring noise when pulling off so will be putting it back to the dealer, and taking up the warranty issue direct with Mazda, great customer service!

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Mon 7 Jun 2010 19:44
Engine emission at low revs - Glenn 42

Looks like Mazda's once excellent reputation for quality seems to be getting a real beating on here. I hope if faults like engines failing and cars accelerating on their own become more widespread, they do a Toyota and recall every one of the model affected, extend the warranty period and do any repairs for free. I was thinking about buying a Mazda next year, but these stories are putting me off.

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Tue 8 Jun 2010 12:03
Engine emission at low revs - turbo11

Glenn 42. I wouldn't let a few bad posts put you off purchasing the right Mazda. We have had three from new in our family and all have been extremely reliable. A Mazda 3, 5 and 6.

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Fri 11 Jun 2010 13:31
Engine emission at low revs - Burnout2

Likewise. I've run the 2.3 DISI turbo in my Mazda 3 MPS for 55k faultless miles, and have no doubt that the next 55k will be equally trouble free. All it needs is 99RON petrol, sympathetic treatment when cold and rigorous observance of the 9k service intervals. Almost all the problems I've read about appear due to owner modification or negligence.

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Wed 30 Jun 2010 21:29
Engine emission at low revs - Woodsy

I bought a 2 year old CX7 with 9500 miles on the clock 2 months ago, 3 weeks ago it started to smoke occasionally after a few minutes at idle. 2 weeks ago it started to smoke after hard acceleration. Booked it straight into my local Mazda dealer who is now replacing the turbo under warranty;The only problem is, there aren't any in the country and the dealer can't as yet tell me when they can get one.

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