Octavia vrs pd 2008 running fault and smoke

[Blue86]

Hi, I'm new here and hope someone can please help, I have a 2008 octavia vrs diesel pd and I'm having a few issues. I had a new dpf fitted this time last year and the car has been fine until about three weeks ago, often under acceleration inbetween 2500 to 3000 rpm it hesitates and jerks for like 2 seconds, and it also sometimes smokes quite bad too, booked the car in with Skoda who checked egr, dpf and all exhaust sensors and they could not fault the car but agreed it did smoke a little and they noticed like me that on occasion it hesitated slightly under acceleration, they also checked for leaked oil in my intercooler and hoses and did not find anything of any concern. Any ideas what could cause this? I am worried it could be injectors? Or turbo? Any help or advice would be great as I'm pulling my hair out with this Now! Haha thanks in advance.

 

Al

[bradh]

What colour is the smoke , also can you smell it what does it smell off 

[Blue86]

Hi bradh, the smoke is white/grey it has only smoked a few times. Main issue is when accelerating it is very hesitant and slightly under powered it is worse in 3rd and 4th gear when it gets over 2500 rpm. Smoke smells slightly like burnt fuel. Only fault code Skoda could find was outside temp sensor was not working a tech I know said this could have a factor as car would think more fuel is required if faulty sensor was saying outside temp was cold? Also I did not no the fuel filter should be changed every service? Last year I just did oil and filter and not fuel filter. Could a blocked fuel filter cause my issue? I hope it is not a injector! But it starts fine every morning? Sorry to go on and On! Thanks for the reply. Any help much appreciated! Cheers 

[JacksVRS]

I do know a regenerating DPF will cause hesitation and jerking under acceleration and even produce some smoke or other cr*p during regeneration. Does it run on the reV counter below 900rpm? Or is anymore harder to run or effect on mpg? As during the regeneration more fuel is injected in and the car will run over 1000rpm.

 

[tonyuk74]

Could well be early sign of egr. Had a Audi A4 2.0pd in work last week. Car had been to another garage in last few week and had a new dpf fitted due to been blocked and apparently new seals in turbo. Car came to us with blue smoke on over run and idle and black on acceleration . After checking it over we found the dpf was again blocked and turbo cold side was full of oil due to too much back pressure. New turbo and dpf again and car was still  heavy black smoking and hesitation up to 3000rpm then power was back . Fault code for mass air flow was the only one present but live readings were fine.  We blanked the egr off and Power was back and smoke eventually cleared. 

[Blue86]

Jackvrs and tonyuk74, thanks for your replies. I think I've noticed my mpg is down slightly, the car idles at about 800-900 rpm and starts fine, this is probably just coincidence but on Thursday I put redex in the car and the the jerkyness has gone through acceleration but it does still feel slightly flat at around 3000 rpm, I wonder if the redex has cleaned my injectors slightly do you think that's possible? never used redex before because thought it was just to good to be true. Im in the trade  (bmw parts advisor) and have my car in work tomorrow to have oil filter and oil changed and also the diesel filter because did not realise the diesel filter has to be changed every oil service! Wondered if a blocked diesel filter could be starving a steady flow of fuel to the injectors? Got to be worth a punt! First thing one of the techs said to me at work was it is probably an egr issue but when I took it into Skoda the only fault code I had was my outside ambient temp sensor did not work? Thanks for the info, will see what happens after diesel filter is changed tomorrow, cheers.

[Blue86]

@tonyuk74 I'm debating getting my egr blanked off, have you blanked many off then? Was just wondering how straight forward it is And can you get eml lights come on because egr has been blanked off? Thanks.

[tonyuk74]

You may get light on. Apparently the a4 has been mapped and egr turned off. Unfortunately exhaust gases were still blowing past. The a4 was easy to blank off. Egr was on the inlet manifold. Just made a blank out of alloy plate and put between egr and the pipe. 

Edited 28 May, 2018 by tonyuk74

[andy-fisher]

I got a light on mine when the EGR was disconnected (removed vacuum line).  Didn't come on straight away though.  I get a little hesitation under light acceleration which I believe is my EGR as when I disable it, the hesitation stops.  I had EGR insuffiecient flow which I fixed using a second hand vacuum solenoid unit which is what i now think is causing the hesitation.

[tonyuk74]

Only needs to be a bit of carbon that stops it closing fully and you will feel the effects 

[Blue86]

Hi everyone, right I'm very relieved to say my running fault is now sorted! It must have been the fuel filter as had my car serviced at work and the tech who done the service said he had never seen a fuel filter like it, he said I my have had some bad fuel at some point which my have caused it to be so blocked? Car was serviced on Tuesday and has been sweet as a nut since and no smoke either so far! Thanks everyone for replying and help much appreciated. Thanks al