Can a diesel engine have pre-ignition? On these cold mornings my engine makes a sound like an old petrol engine "pinking" when I accelerate. It lasts until the engine gets warm, maybe 3-4 miles.
The car has done 50,000 trouble free miles, I hope there is no fuel pump problem as mentioned on this site.
kingslea.
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I am new to a Mazda6 diesel (only 3100 miles) but mine starts and runs fine in this colder weather. Still quiter than the Mondeo TDCi was too.
Hoping you do not have a problem with your car.
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That doesn't sound like the typical pump problem. I'd take a guess that there may be an injector fault developing; so it might be an idea to get the dealer [if warranty] or a diesel specialist to look at it.
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thanks for the advice, unfortunately it is out of warranty.
kingslea
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I have had a 6 estate 136 diesel for 3 years and notice the same pinking noise that you are hearing, it is quite loud sometimes and even my wife comments on it! It only occurs at part throttle, if you floor it the noise disappears. But it only occurs during cold summer mornings for about 3-5 miles. As soon as the fuel companies switch to winter diesel in October or November the noise disappears and all through the winter no matter how cold I never hear the pinking. Then it comes back again in the spring.
I have written to Mazda about this, and other problems with the car, and I got a surprisingly intelligent reply about most of the problems (and a free service!) but they claim not to have heard of the pinking problem. They suggested I have the ECU injector learning function reset to the factory setting, which I did. This made the engine noisier overall for a while and I did not hear the pinking. After a while the engine got back to its usual smooth running and the pinking returned!
I have stopped worrying about it but am still curious as to what causes it and why the slight difference between summer and winter diesel (only anti waxing additive as far as I know) affects the problem. I can only summise that the timing and fueling are set so close to the limit under cold conditions that the slight difference between summer and winter fuel tips the combustion into a kind of high frequency knock.
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I trade in used high mileage diesels, i've had around 6 Mazda 6 and at least 3 of them have done exactly what you describe, I too have referred to it as pinking.
The first 2 i had to send to auction, The last one that i had was sold to a guy who suggested that he was convinced it was a sticking tappet, and he doubted that it would cost him more than £100 to put right, unfortunately I didn't ask him how he got on with it, but to my very limited mechanical mind it all made sense.
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I have the same thing at the moment on my 2.0 diesel / TS (73,000). my mechanic says it sounds like an injector fault he sees lots of on ford TDCIs. - so we decided to have them sent away for testing - only problem is, he cant get them out! they're all completely stuck solid and has now put it back togethor while we think what to do...he doesn't want to snap one.
- anyone know if there is a 'special' tool ?
I'm not happy driving it, so it is sitting on the drive, though it does seem to go away completely when the engine is nice and warm. - and it's got no other symptoms at all - it's quite loud when the engines cold though, but you cant hear it when just revving it on the drive.
he spotted that the EGR was veeeery carbonised this morning, so this might explain the black smoke from the exhaust - but i dont know if we should get that replaced (mazda part is £226) or what to do at all now! - we are trying to sell it anyway...
any one any thoughts?
thanks
glenn
Edited by Dynamic Dave on 05/02/2008 at 12:46
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Most diesels tend to knock when first started;it's because they advance the injection timing to assist cold start.
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i forgot to mention that it hasn't yet had its 75k (big) service. wondering if i should get it done early -even though i'm trying to sell it at the mo. service includes fuel filter/air filter/ + others, so can only help....hmmm...
btw, the cost for this at southampton mazda is £628 inc, or a local mazda specialist will do it for £512 inc. - no need to pay £700+.
it's a definite 'pinking' type noise though, not just a clunky normal diesel startup kind of noise.
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Completely different car and injection system type I know, but my Passat PD130 used to make precisely this sort of pinking noise for a second or two if accelerating briskly / hard in the first 3 - 4 miles from stone cold. Usually around the 2,250 rpm mark, and only for a second or so.
After the 60K cambelt change it stopped doing it, the change must have dialled in the injector timing a wee bit better.
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I really dont know if this is an injector fault (as my web searches have not found any other mazda diesels with the problem identified as an injector), or the thing to do with the ECU reset that 'the engineer' mentions above. - anyone know if this has to be done at a mazda dealer and what it might cost etc? - might be worth us trying it if not too pricey.
do you think we are OK to keep driving it at the moment? - i dont want to do any damage etc (there are absolutley no other syptoms / problems when driving, apart from the odd black smoke which might be the clogged up EGR valve)- 'luckily' we have 3 cars at the mo, so we dont have to use it.
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