Mazda Mazda 6 (2002 - 2007) - May 06 Diesel 143 - misfire at 1250 revs | Technical matters | Back Room Forum

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Sun 24 Feb 2008 21:52

May 06 Diesel 143 - misfire at 1250 revs - vulcan7

Hi all

Have a Mazda6 Diesel that misfires off idle 1250 rev's it's been doing that for a few months sometimes. It's done 23K and had service at Dealers at 12K last May and I changed oil and filter at 18K with Mazda DPF Dexelia. Now last few weeks misfires all the time if you go slow enough in second gear and take it easy. I can even tell in these last few weeks it's not running right up to 2000 rev's. In traffic it's awful feels like it's off on a cylinder. Have to admit that I thought if I took it back to dealer at first they might not notice it but now having checked mpg this week and it's only doing 29mpg am going to phone local mazda dealer tomorrow Monday. Has anybody any ideas what it could be cause, sad to say I worry they will have me running back and forth. Thankfully it's still under warranty for sixteen months still. I was hoping to keep it for at least four years!
Last but not least I did try disconnecting battery all that happened was I got some practice at resetting eletric windows easy enough though!

Thanks in anticipation
vulcan7

Edited by Dynamic Dave on 25/02/2008 at 00:32

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Sun 24 Feb 2008 22:28

Diesel 143 May o6 misfire at 1250 revs - Screwloose

Any number of possibilities; but the high-pressure pump failure that was "cured" in '03, can cause low-rev issues; more usually stalling though.

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Sun 24 Feb 2008 23:29

Diesel 143 May o6 misfire at 1250 revs - vulcan7

Thanks for that Screwloose

Must admit I had considered the pump but it never ever stalls touch wood but that's not to say it could not be that. Sure I heard some talk of problems with Denso injectors a bit ago but can't remember where. Even done a search on this forum but no luck.

Thanks
vulcan7

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Sun 24 Feb 2008 23:39

Diesel 143 May o6 misfire at 1250 revs - Screwloose

I'd have thought that an injector fault would either have put on the MIL light or caused bad hot starting; but anything is possible....

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Fri 29 Feb 2008 18:10

Diesel 143 May o6 misfire at 1250 revs - vulcan7

Hi
Just thought I would update you all. Went to local Mazda dealer (I think that was the word you were actually meaning?) on Monday for roadtest with Technition said bring it on friday. Dropped it off today came back to collect at four pm. Not ready sir be twenty minutes. Anyway twenty mins and it's ready "we cleaned injectors and reset, everything was a bit out. Alarm bells ring in my head! but get keys and away we go. Start up light knock on engine that was not on before, drive off not done fifty yards and misfire is even worse. Stop and walk back explain about noise bring it back Sir ten mins passes o it's seal washer on injector needs a new one we will order one for next week and ring you but take it easy and these people claim to know what they are doing! Would you take it back thats the question give me your views please.
vulcan7

Edited by Dynamic Dave on 29/02/2008 at 18:38

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Fri 29 Feb 2008 18:44

Diesel 143 May o6 misfire at 1250 revs - Screwloose

V7

Sounds like a total load of bullshi...ne to me - they clearly do not know what they are doing. There is no way to "clean" [or even test] CR injectors. There are no fuelling "adjustments" to be "a bit out" - the system is fully self-correcting. [Had they been messing with the injector calibrations in the ECU?]

With this new knock, could this be a dual-mass flywheel fault; it doesn't tally with bad fuel consumption, but "misfires" at low revs are common on those when they go out of balance.

So to this "seal washer" will cure it - will it? Is it leaking diesel or combustion gas? If the latter; it will quickly trash the injector liner and make the injector almost impossible to remove. "Take it easy;" is not what you say to a customer with that sort of fault - either it's safe to drive normally, or you give them a courtesy car.

Once again it appears that your dealership is, yet another, that has no-one left that even understands how they work, let alone how to diagnose a CR. Insist that they call-in the area tech rep to look at it. [He must be a busy chap working for Mazda.]

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Fri 29 Feb 2008 23:32

Diesel 143 May o6 misfire at 1250 revs - vulcan7

Just what I thought Screwloose
To be honest when I heard the knock it sounded like a little end or piston slap but it could be too advanced if thats possible. What worrys me is they would have let me just go and and not have said a word if I had not gone back. Receptionist said don't worry it's under warranty, needless to say brought it home few miles and it's parked up. The misfire is worse than ever now from 1000 to 1800 great job. Wished I had left it as it was now.
Tomorrow will take plastic cover of top of engine and see if injectors have been out. I also now have a noise like a tight belt as well, that I've not heard before but I may be getting paranoid.
The tech area rep sounds like a very good idea before they do some serious damage if that's not already been done. Got to say things are bad at dealers even when I worked in small Mazda dealer in eighty three we would never have turned a job out like that knowingly.

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Fri 29 Feb 2008 23:49

Diesel 143 May o6 misfire at 1250 revs - Screwloose

V7

Have a look round the injectors for evidence of oily, combustion gas leakage. If that leak's so bad that it's your "knock," then it should never have left the workshop.

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Sat 1 Mar 2008 08:55

Diesel 143 May o6 misfire at 1250 revs - Galad

Screwloose, is the Mazda 6 diesel engine shared with any other manufacturer? The woes expressed in this and the recent Mazda 323 diesel threads have totally disabused me of any notion I ever had of investing in a Mazda common rail diesel. As I've said before, I'm a loyal fan of the old 323 TD which has never missed a beat in 6 years and nearly 85k miles but how this contrasts with the new models! Mazda's reputation for quality and reliability is on the line in my book.

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Sat 1 Mar 2008 09:36

Diesel 143 May o6 misfire at 1250 revs - LinuxGeek

Galad I must say even I'm a devoted fan of Mazda's reliability. I've got a Mazda 323 2.0TD and so far its been spot on and its got 112k on the clock now. Just wondering why the new diesel engines are turning out to be so unreliable? I believe these engines are PSA sourced and not Mazda's own, is that true?

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Sat 1 Mar 2008 11:25

Diesel 143 May o6 misfire at 1250 revs - injection doc

could be an injectors causing the knocking! Are these injectors coded on mazda's or not? coding on mondeo's cause misfire at very specific RPM ,normally 1250 1750 & 2250 rpm & on very light throttle feel like they are running on 3 1/2 cylinders.
Just a thought.
Doc

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Sat 1 Mar 2008 13:54

Diesel 143 May o6 misfire at 1250 revs - Screwloose

AFAIK this is a Mazda unit; it's possibly related to Fords Puma, but significantly different.

Doc

I was wondering the same; hence the comment about them messing with the injector calibration figures. I wouldn't think [hope] that Mazda are using injectors that need individually-tailored software correction to overcome manufacturing deficiencies...?

My scanners don't have injector re-calibration programs for this unit; have you ever come across it?

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Sat 1 Mar 2008 14:19

Diesel 143 May o6 misfire at 1250 revs - injection doc

Hi Screwloose, no to be honest apart from a friend having a mazda 6 I havent had any involvement with one. I may look up all the tech info when i get to work on monday but like you I would hope they don't have tailored software correction but there again anythings poosible.I will speak to the hardware & software engineers on monday & see what they can tell me about a M6.
Doc

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Sat 1 Mar 2008 18:53

Diesel 143 May o6 misfire at 1250 revs - vulcan7

Hi all
Had engine cover off this afternoon everything looks perfect and untouched I'm pleased to say. Sad to say mazda dealer tech have just given me a load of pink fluffy dic. It's one of the oldest tricks in the book. Used when tech don't know what he is doing. Need's new part before we can fix then hope other tech gets job when it comes back! I've never heard diesel engine running with loose injector but a petrol engine with loose plug sounds terrible you can tell without lifting bonnet, thats for sure. Injection doc bet you've hit nail on head with your diagnoses I think but could that problem be due to changed or lower pressure on hp fuel pump which is a known problem with this engine as screewloose suggested. Got to say I had a little Mazda 323 petrol for 13 years and 140k and it was a geat car. Simple and easy to work on too.

Edited by Pugugly on 01/03/2008 at 19:08

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Wed 8 Dec 2010 16:44

Diesel 143 May o6 misfire at 1250 revs - camara

hi got the same problem on my mazda 6. judder at 1250 revs to 1500 revs. did you find out what it was?

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Fri 10 Oct 2008 22:37

Diesel 143 May o6 misfire at 1250 revs - Bartmania

The 136 BHP unit does use the injector calibration figures (stamped/laser engraved in the top of the injectors), which can be entered by some software that at least Mazda shops have.

My '6 had it done numerous times - I experience similar problems to what vulcan7 describes.

So far they have tried
- injector clean
- replace flywheel
- clean EGR valve
- recalibrated injectors & MAF sensor

but all to no avail.

I'm thinking about asking a diesel specialist to replace any injector they think may be defective - apparently it cured vulcan7's Mazdarati.

BR
Bartmania (Denmark)

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Sun 12 Dec 2010 22:20

Diesel 143 May o6 misfire at 1250 revs - camara

did you find the problem?

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Wed 6 Aug 2014 22:14

May 06 Diesel 143 - misfire at 1250 revs - recombo

I had the same problem with my Mazda6 05 plate, 40k mls - jerking and hesitation at 1250rpm and engine warning light coming on (misfire on #1) when idling for long periods.

The problem was no.1 injector was sticking. Apparently it was not opening until 400bar when it should open at 170. Took it to a diesel specialist and he unstuck & cleaned injector for £85 plus 3.5hrs labour - total ~£300. Now the engine is running beautifully, smooth as.

I think the injector got stuck due to us doing a lot of town driving, so am now going to use fuel injector cleaner / Diesel Rhino more often to keep it all clean.

The mechanic reckoned that the Mazda 6 TD engine "is an abomination" - his words!

Basically, the design is 20 years old, 60hp unit, but they just kept adding more and more stuff to it to eventually up the power to 130hp + all the emissions stuff. No wonder the pipework in there looks like a rats nest!

Now they [Mazda] have given up with that engine and are using the Peugeot TD unit instead in their SkyActive range. Apparently the French are really good at doing TDs.

PS. Don't believe all the BS on the internet about dual mass flywheels - that's not the problem.

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Sun 26 Apr 2015 18:13

May 06 Diesel 143 - misfire at 1250 revs - Digit-Al

Had the same issue since I bought the car 5 years ago.

Still not fixed, however, noticed the Management light only comes on if the outside temprature is over 10 Deg Centigrade.

Doing a check on the cars computer shows a fault from the temp sensor at the MAF. I've cleaned and checked it, resistance varies with temp changes at the plug.

Does anyone know where in the car the MAF plugs in to (computer end, not the obvious bit on top by the air filter)

Tracing any cables in there is a nightmare!

2006 Mazda 6 Diesel. (now with 140,000 miles on it)

ps runs 60mpg when the MIL is on !!! (over 10 deg outside temp)

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