Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

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DaveS48
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Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

Post by DaveS48 »

Hi all, new to the forum. When I start the engine from cold it idles ok for about 30 seconds and then becomes very uneven to the point where it is uncomfortable to sit in the vehicle. Once the engine reaches about 50 deg C it settles down again and is a nice smooth tick-over. My main VW dealer has run it through all the usual diagnostic checks and says there is nothing wrong! I can't believe this is normal. Has anyone else had similar problems or can suggest a cause /solution.
Thanks.
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jammydodger
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Re: Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

Post by jammydodger »

I have the same engine and my sister has the 75ps version and neither of them do this. This week has been especially cold in the mornings (-2C to 1C) and they have started and idled fine.

Your symptoms sounds very similar to an issue I had with my last Polo, a 1.2 TDI. This car ate through 3 fuel pressure sensors and idled very rough when cold.
DaveS48
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Re: Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

Post by DaveS48 »

Thanks jammydodger. I'll look into your fuel pressure sensor theory. I just knew it wasn't right, the problem is convincing the VW dealer as by the time I get it there the engine is hot and the idle is perfect. The car starts every time, without a problem, no matter what the outside temperature seems to be and it's only during the warm up period that the roughness happens. The other thing I have noticed is the fuel consumption is poor so I think it could well be what you say.
Thanks again.
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Re: Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

Post by alexperkins »

Get them to keep it overnight and test it from a cold start in the morning - any decent dealer will do that
DaveS48
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Re: Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

Post by DaveS48 »

Thanks both for info. However it now appears that occasionally the engine will run smoothly and return good mpg figures. When I start the engine in the morning it will either run at 978rpm in which case it will run roughly all day with the subsequent poor performance, or at 825 rpm in which case it will run very smoothly and returns much better consumption figures! More often than not it ticks over at 978 rpm and there seems no way of knowing which and no way of changing it. I am now trying to build a case to present to the VW dealer.
Can I ask jammydodger what his rev counter shows when his car ticks over. (I believe that 825 rpm is what it should be).
DaveS48
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Re: Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

Post by DaveS48 »

Well what a week. After months trying to convince my local VW dealer that I had a problem I was out driving the other day, when the dash lit up like a Christmas tree, with warning lights. The car was taken to the dealer and after 3 days they decided that the 'FUEL PRESSURE SENSOR' was faulty! This was changed and the engine is now much smoother etc! Thanks jammydodger! The engine may be running better but I am still getting rubbish MPG. I was getting about 51 mpg before, even when driven very carefully, now I'm getting about 58 mpg, (this was mainly open road), a slight improvement but nothing even approaching the 71mpg (Urban), 91mpg (Extra Urban) and 83mpg (Combined) that is advertised by VW. Whilst I do not expect to get VW figures, I do expect to get alot nearer than I do. I was able to get pretty close with my previous car, a Ford Fiesta 1.4 TDi, so why not the Polo?. In fact the Fiesta produced better figures than the Polo! Can anyone with the same car/engine, (6c), let me know what sort of figures they get.
Thanks.
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jammydodger
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Re: Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

Post by jammydodger »

Glad to hear it's sorted now Dave :)

MPG wise, going to work I go through local roads (17 miles) all of which are 30MPH with a 3 mile stretch of country road at 40MPH and on average I see anywhere between 55mpg - 64mpg. Driving around from site to site when at work 4/5 miles max each I see 45-50mpg (driving like I stole it) then going home I stick to the M60/M62 and due to the 50MPH speed restrictions at the moment I generally hit 65-73mpg very easily (79mpg once by sticking behind a lorry doing 54mph).

Do you have your ThinkBlue Trainer on when you're driving? I find I'm much more conscious of how I drive when I do have this on and have learned how my car likes to be driven.
DaveS48
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Re: Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

Post by DaveS48 »

Thanks again jammydodger. Yes I do have the 'Think Blue' on virtually all the time and find it a great help. Your figures are very interesting. I have never been able to get my mpg into the 70's what ever I do. On the motorway sticking at 56mph I can just about manage about 64mpg. Not great for a car that is supposed to do 83mpg average!! I still think I've got a problem and your readings seem to confirm it - more ammuntion to put to the dealer/VW. Thanks and I will report back with any developments.
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Re: Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

Post by George1997_6rTDI »

jammydodger wrote:I have the same engine and my sister has the 75ps version and neither of them do this. This week has been especially cold in the mornings (-2C to 1C) and they have started and idled fine.

Your symptoms sounds very similar to an issue I had with my last Polo, a 1.2 TDI. This car ate through 3 fuel pressure sensors and idled very rough when cold.
I'm currently driving a 1.2 TDi and I've noticed the car is idling just above 1k rpm recently instead of the 8-900 rpm it usually ticks over at.
Mine is also not returning very good mpg either, about low 40's max, the car still drives perfectly though and doesn't seem to be a lack of power.
Is there any way you can shed some light on this for me? And if it does sound like fuel pressure sensors, how much am I looking at for one?
Cheers
DaveS48
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Re: Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

Post by DaveS48 »

Hi George. I'm sorry I haven't a clue what the cost of a fuel pressure sensor is as mine was changed under warranty. However there has been an improvement since have the new one. However I still seem to have a problem - some days it will idle at about 980 rpm and other days it will be 820 rpm. When it idles at 820 rpm it seems so much better, more responsive and better mpg. The VW dealer has no idea why and I'm still doing tests etc. Egr valve appears to be most likely from enquires so far but it early days. I will post any further info when I get. Still would like to hear from anyone with similar problems.
DaveS48
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Re: Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

Post by DaveS48 »

Still pursuing my poor running issue and the replacement fuel pressure sensor has made little difference. There is a slight improvement on fuel consumption but the idling is still bad. Some days it will idle perfectly at 820 rpm and others it will be really rough at 980 rpm. I have obtained an OBD2 tester which does, on occasions, suggest that the EGR valve, , is playing up, even though it's only done 7300 miles, and there are no fault codes recorded! Has anyone else experienced EGR valve problems and if so what were the symptoms and/or fault coded? It's booked in for it's third visit to the main dealer next week and it would be good to have some evidence present to them.
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Re: Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

Post by Unsworbw0 »

I purchased my polo as a used vehicle. The car was fully serviced but on the morning I collected the car the dealer explained that it was lumpy on start up but was due to new filters and it would settle. After about 15 miles the temp rose to 115 so I took it back. The dealer said that the car would do a re-gen which would allow the temp to rise but it would settle, after 6 weeks it hasn’t so they have taken it back and the idle at start up is actually worse. I await.the return of the car as it’s now with them for investigation. I will however say that all through this my car actually returns 94-96 mpg on my 28 mile commute around the m60. Around town I get anywhere between 54-64 short couple mile runs.I am restricted to 50-55mph on my commute and rarely hit traffic so early.
DaveS48
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Re: Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

Post by DaveS48 »

Hi UnsworbwO. I have to say that I gave up on my 1.4Tdi 12 months ago. Despite numerous visits to my local dealer the problem was never solved and I exchanged it for a 1.2 tsi bluemotion. They kept telling me that my car was running correctly! The fuel consumption was terrible at about about 58mpg even on a good run of 250 miles down the M5 to Cornwall and the dealer said this was what they expected!. The 1.2 tsi, over the last year, has proved more economical than the diesel with little more on average mpg but, on a good run, I can get 65 mpg and is a dream to drive. If I had got anything like 90 mpg I would have been over the moon!.
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Re: Polo 1.4 Tdi SEL Bluemotion (2015 model) - Poor idle when cold

Post by Unsworbw0 »

Update, I need to add the idle on my 64 reg 1.4tdi SEL actually does only last approx 30 sec to a minute but it sounds rough when driving for the 1st half mile then absolutely fine. However the car is currently now with the main dealer. Would just like my car back really. As far as the temp is concerned I’m told it’s a temp sensor problem but the mechanic at the local dealer gave up on that too before giving my car back to VW. A WEEK IN A FIAT PUNTO has been a very sobering experience so I hope VW can work some magic.
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