Car bother

Discussion in 'Off-Topic Discussion' started by clueless1, Jan 6, 2016.

  1. longk

    longk Total Gardener

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    Or the timing belt! They had a habit of snapping at the best of times.

    A perfect illustration of the importance of live data over fault codes.
     
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    • clueless1

      clueless1 member... yep, that's what I am:)

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      I'm told that mine has a timing chain rather than a belt. So I shouldn't need to worry about that.

      Oil was flushed and changed about 6 months ago, when the turbo was replaced. At that time they also steam cleaned the entire induction side. There was concerned (raised by the mechanic) that the oil vomit from the turbo failure could snot up the egr, as well as the O2 sensor, but he said I'd know within days if that happened.

      It did a couple of misfires today, but for the most part, it runs like new.
       
    • Fat Controller

      Fat Controller 'Cuddly' Scottish Admin! Staff Member

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      I think you are right @clueless1 - if I remember rightly, it was the following dci engine (the forerunner to the engine that I have in mine) which was known for the timing belt going out to lunch prematurely; quite a few Nissan Qashqai J10 owners suffered that fate, along with a load of Renault owners.

      Incidentally, don't be tempted to repeat the oil flush on your engine - they would have no choice but to do it after the turbo took the side exit, and it was absolutely the right thing to do especially as it was done professionally, but under normal circumstances those Renault lumps are not supposed to have a flush ran through them - apparently it doesn't all come out, and lives in the upper oil galleries, and then dilutes the new oil rendering it a lot less effective than it should be... the rest, you can imagine.

      If the misfire isn't that bad, pop to Halfords and get yourself a bottle of Millers and double dose it, then wait for that tankful to run through and double dose it again on the next tank - - as you get through the second tank, it will have started to do its thing and you might just find that it is sufficient to solve your problem. Thereafter, you only need to single dose it really, unless of course you want that wee bit more grunt. Its about £15, so not too much to spend as a bit of a gamble, and it isn't going to do any harm even if it doesn't sort your problem.

      I have heard good things about ZX1 also, which is a chemical that bonds with the metal (none of the usual teflon type substances that are quite nasty either), and reduces friction etc; apparently it was developed for F1, however I haven't used it myself (yet) so cannot really comment too far. It isn't an oil treatment, but it does use the oil as a carrier to get to where it needs to be, and it needs heat of 60º before it will bond with the metal, however it can also go in with coolant and fuel to protect pumps etc. It has all the hallmarks of being a 'snake oil' to me, but there is quite a lot of info kicking about on the net (including YouTube) which infer otherwise.
       
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      • clueless1

        clueless1 member... yep, that's what I am:)

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        Car is in the garage. Not because of the engine woes, just routine. It's getting a suspension bit done that has simply worn.

        I did get the codes read while it's there. Mechanic said a number of codes were logged, and in his experience (he is an exceptional mechanic, his experience counts for a lot with engine matters), they all point to excess carbon build up. Ie no components have actually failed, it's just "full of snot".

        He recommended 'terraclean'. But it's expensive. He said £200 plus vat. A web search seems to suggest that's above the going rate. He did say that a good fuel treatment will help a bit, for a while, but would not be a long term solution.

        My thoughts is that in this weather, my car is never reaching normal operating temp. The temp gauge never gets past about quarter the way across, whereas in summer it sits smack bang in the middle. This gets me thinking it can not burn at max efficiency, so it will snot up again fairly quickly at this time of year.

        The mechanic thinks it is unlikely to just drop dead. Most likely just reduced performance. I can live with that for now.

        Any thoughts? I could bite the bullet and have this terraclean process done sooner rather than later, or I could buy some Forte turbo diesel treatment and give it a good ragging.

        One thing that worries me a bit with the terraclean option is, what if it's only carbon deposits that's sealing ageing joints in the manifolds etc.
         
      • longk

        longk Total Gardener

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        That's the least of my worries - I've had diesel cars bend valves when bits of crud in the inlet manifold dislodge and get stuck under the valve seats. Now I'm not saying that it will happen but I am saying that it is possible. However, the Terraclean injector clean service is safe enough as it deals with the fuel side but will not clean the carbon build up in the inlet/EGR.
        Just one thing, carbon build up is not really intermittent. Having said that he has seen the car, I haven't. Did it play up whilst he was looking at the live data?
         
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        • clueless1

          clueless1 member... yep, that's what I am:)

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          The mechanic said it cleans the inlet side including the egr.

          He didn't do much being reading and interpreting the codes because thats all I asked him to do today. The primary job was to replace a worn lower arm.

          Mechanic said to use a good fuel treatment and give her a good thrashing for now. He also asked me questions about my driving style and then gave me a polite telling off when I said I always drive in the highest gear I can get away with. In my car, in top gear at 60mph, she only revs at 2000rpm. Apparently with a modern diesel you have to use the rev range occasionally.

          Codes were:
          Intake air temperature, faulty signal.

          Air mass sensor, incorrect function.

          Fuel system pressure, incorrect pressure.

          Glow plugs, glow plug failure.

          The last one I believe, because it once felt like it had started on 3 cylinders and then the fourth fired up when I revved it.

          First two remind me of my first Volvo that always reported a failed MAF sensor until I fixed an ignition fault. If the o2 signal massively contradicts the MAF, then the MAF gets blamed when it's actually done it's job right, but the burn was inefficient for other reasons, leading to more oxygen in the exhaust than there should have been.

          The EGR one is in my opinion probably key. As I understand it, a misbehaving EGR will seriously mess with the mix.

          I have no idea about the fuel pressure one.
           
        • Fat Controller

          Fat Controller 'Cuddly' Scottish Admin! Staff Member

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          Terraclean seems to be reasonably well respected, but I am not convinced that it would sort your problem out.

          I would be more inclined to look a little deeper at those fault codes - firstly, the air temperature sensor; if that is reading the wrong temp, and is under-reading, the ECU will be chucking more fuel in than it needs to - the rich running will only serve to increase the snot building up.

          MAF failure - that could also be part of the problem, however I would sort the air temp sensor first and go from there. I can't see an air temp sensor listed on Euro, so you might have to go to a motor factor to get you one.

          Glow plugs - that is almost certainly correct, and it is telling you that you have one or more duffers in there; normally, the diagnostics measure the resistance and circuit integrity when you start the car; it is extremely doubtful that this code was chucked up by a ropey start, however the ropey start was almost certainly caused by a duff glow plug. They are available for less than a tenner each, so if you were going to throw a few quid at it, start there and do all four. Again, this could also lead to rough running and too rich a mixture being chucked in, resulting in unburnt fuel.

          The MAF is the expensive blighter at around £85 - been there, done that, but thankfully it does generally make a hell of a difference once it is sorted (and fuel economy usually improves significantly); you can more often than not verify if it is duff by getting the car up to temperature, then switch off and disconnect the MAF (just pull the plug out) and take it a short drive -- if it feels more sprightly, then your MAF is goosed. Don't run it too long like that though.

          Finally, your mechanic is right - strangling any small turbo diesel engine by keeping it at low revs is going to fill it full of crud in no time. I still say to try the Millers, double dosed for the first two shots, and start using the rev range a bit more (up to 3500 ish); you won't use that much more fuel, and in fact will probably save fuel in the long run as it won't be fighting to breathe.
           
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          • longk

            longk Total Gardener

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            Depending on the set up the air mass meter frequently houses the intake air temp sensor too.

            Perished fuel hose allowing air into the system. Faulty sender. Failing pump. Failing injector.

            Easily diagnosed with a multi-meter.

            That is easily clarified by checking the hydrocarbons.

            You had and EGR fault code as well? What was that?

            This one is the most likely cause of the intermittent issue you have. A choked inlet will not cause intermittent misfires, an airmass fault could be intermittent but would not produce a misfire.

            Get the codes reread after it has messed about again. As with all faults check the wiring using voltage drop tests if possible before you start chucking money at parts.
             
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            • longk

              longk Total Gardener

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              That is the one that I would not like to use. The fuel system clean is good, better than Forte (from the two times that we used the local agent) but bear in mind that the laquering of injectors can mask wear issues. Cleaning to such a high level can expose wear issues.
               
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              • clueless1

                clueless1 member... yep, that's what I am:)

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                Sorry, I thought I'd typed the egr one. Must have just thought it instead.

                It said EGR, incorrect operation.
                 
              • longk

                longk Total Gardener

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                Ok, EGR and air mass faults usually tie in together - could be either. Is the EGR electrically operated or vacuum operated?
                 
              • Fat Controller

                Fat Controller 'Cuddly' Scottish Admin! Staff Member

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                @longk - it is electrically operated (I just looked it up) Siemens VDO unit as OEM
                 
              • clueless1

                clueless1 member... yep, that's what I am:)

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                If I get another year out of this car, I'll be happy. I don't envisage keeping it much longer than that so I'm reluctant to spend more money on it than I really need to.

                I think after reading the codes, the garage reset everything, because she drives like new. The mechanic did say he thought it would play up again though if left untreated, but recommended I choose a reputable fuel additive/treatment for now if I don't go for the terraclean.

                Car starts every time (so far), so I'm reluctant to spend more dosh just now.
                 
              • Fat Controller

                Fat Controller 'Cuddly' Scottish Admin! Staff Member

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                If I were you, I would spend any money on a few sensors (assuming you can prove it needs them of course) and maybe a fuel additive; that £200 for terraclean would give you so much more in parts that are identified as failing.
                 
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                • longk

                  longk Total Gardener

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                  Then my gut feeling is that the MAF will also be VDO. Probably 5 wire meaning that the air temp sender is part of it. As the code was not "EGR circuit A" or similar it kinda points to a MAF fault (ie it has deduced an EGR fault based on the lack of change in the MAF reading). Not gospel but an educated guess without the car. Remove the EGR and check for blockage to rule that side of it out first though.
                   
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