OT: Mazda 3 losing performance

[Endulini]

Hi,

Apologies for the OT post but there's a wealth of good advice in the group...

I have a 2008 Mazda 3 TS2 Diesel Saloon and have noticed a recent drop in the engine performance in terms of the mpg. Where previously I was able to get a quite comfortable 60mpg (as measured by the on-board computer) I'm now struggling to get 53-55mpg. Whilst I don't place much credence in the actual figures it's the downward trend that concerns me. The last time this happened it was the beginning of a sequence of events where the car would suddenly lose power and eventually I had to get the fuel filter changed after the car totally gave up. Is this a known issue with Mazda or diesels cars in general (I was under the impression that these filters are self-cleaning)?

[js.b1]

You may want to see if there are any engine codes. This may require a) dealer or workshop visit or b) buy a code reader (from = a seller guaranteeing it works etc, can save you =A328-150 a time - used to= be =A328 to read a code, now I think some main dealers charge =A385+!).

Likewise, are your journey's short or long - a longer journey gives the Die= sel Particular Filter more time to Regenerate. The fuel filter is quite dif= ferent, and they do have a service routine (check the car manual as a rule)= .

You may want to also ask in

technical discussion area;= there are actual mechanics and other owners there who may at least be able= to give a bit of advice. In particular, some "gotcha's" about that particu= lar year / model of car re what to look out for AND cheaper workarounds. We= ll worth doing a maintenance "dig" so you know your ownership risk and can = budget accordingly, such as 30-50/month for that "just in case".

Of course, if it were a Ferrari, you pay half to buy it, then half again to= maintain it over the subsequent 10yrs and no I am not kidding :-)

[The Natural Philosopher]

seller guaranteeing it works etc, can save you £28-150 a time - used to be £28 to read a code, now I think some main dealers charge £85+!).

Particular Filter more time to Regenerate. The fuel filter is quite different, and they do have a service routine (check the car manual as a rule).

there are actual mechanics and other owners there who may at least be able to give a bit of advice. In particular, some "gotcha's" about that particular year / model of car re what to look out for AND cheaper workarounds. Well worth doing a maintenance "dig" so you know your ownership risk and can budget accordingly, such as 30-50/month for that "just in case".

maintain it over the subsequent 10yrs and no I am not kidding :-)

cold weather destroys diesel efficiency on short trips. They take time to warm up and chew fuel in the process.

If yours has a glo plug leave the engine for a few seconds with ignition on, top make sure it starts smartly.

Other possibles are binding brakes and flat tyres.

Or a leaking turbo hose. If its a turbo.

[Endulini]

Likewise, are your journey's short or long - a longer journey gives the Diesel Particular Filter more time to Regenerate. The fuel filter is quite different, and they do have a service routine (check the car manual as a rule).

You may want to also ask in

technical discussion area; there are actual mechanics and other owners there who may at least be able to give a bit of advice. In particular, some "gotcha's" about that particular year / model of car re what to look out for AND cheaper workarounds. Well worth doing a maintenance "dig" so you know your ownership risk and can budget accordingly, such as 30-50/month for that "just in case".

Of course, if it were a Ferrari, you pay half to buy it, then half again to maintain it over the subsequent 10yrs and no I am not kidding :-)

Thanks :). I do mainly longish journey 65-70 miles...

[Dave Liquorice]

A self cleaning filter, interesting concept. Where does the cack that it= filters out go? I guess you could have some sort of backwash system and =

flush it all back to the tank to be filtered out again until the fuel in= the tank got so filthy the system couldn't cope and the filter blocks starving the engine of fuel.

I don't know about that particular make/model of car and it's fuel filte= r but I've never heard of a fuel filter that didn't need to changed as a service item every so often. And doesn't the fact you've had similar problems before tell you something? How much does a filter cost? =A330?=

[Mike Tomlinson]

En el artículo , Dave Liquorice escribió:

Maybe he's thinking of the wotsit that removes water from the fuel?

[harry]

You may need new injectors. As they get old, the hole gets bigger resulting in poor vapourisation and bigger fuel droplets. This results in incomplete combustion and sometimes black smoke from the exhaust.

Does it have a catalytic converter? If so it may just need a high speed motorway run to burn out the carbon. You need t look after your cat, they are easily damaged and expensive to replace. Carbon buildup is the quickest way to destroy it.

Or you may need a new air filter.

[Dave Liquorice]

That's normally part of the fuel filter design, it forms a low point in the system for water to collect in. When the filter is changed any collected water is also taken away. There maybe a water sensor that lights warning light on the dash if the filter gets too wet.

[Man at B&Q]

Faulty EGR system had that effect with my Ford Diesel. Also creted a lot of smoke when booting it.

MBQ