Smoking on idle, injector seals

wigandill

Registered User
Made another thread but cant seem to find it.
I have a intermittent smoking problem on idle, Seems to come and go mainly when warm but can also do it when cold. Some days its preety clean and clear other days it chucks loads out.
Seems to be a grey/white colour maybe with a blue tinge.
I have swapped rocker covers with a mates as read somewere the breather (pcv) can become blocked and cause the issue, this made no diffrence
Turbo should be ok i imagine as it is less than a month old.
Inlet manifold has been swapped for a bkd one without the flaps and fitted with new gaskets (the engine oil washes past a gallerie in the mani on its return to the sump)
Egr has been deleted along with egr cooler and also decatted
Does have a hybrid fitted but no oil in downpipe or boost pipes (bare the usually small amount which these car breath).

I am now starting to get to my witts end with this issue and if it dosent get solved i will be breaking the whole car down for parts which is a shame.really as it is immaculate with 1000s spend on mods

I plan on doing the injector seals in the morning as a last ditch effort to cure this smoking issue.

The car runs fine, idles well and pulls like a train, apart from if the revs are held at around 1600ish rpm then it seems to either miss or shudder, failing injector maybe or just seals

My indy recons seals so i will do them myself 2moz and report back.

Any help info or advice on this would be much appreciate
Cheers
 

Mario

Registered User
Could be the MAF sensor. If it is dirty or faulty it will give false signals to the ECU and will inject too much or too little fuel which can cause smoking, missing, etc.

I would try cleaning the MAF first, if the ECU doesn't know how much air is coming into the engine then it will never know the correct volume of fuel to inject. Idle is the hardest thing for the ECU to deal with, it's a fine balancing act to keep the revs stable, hence a dirty MAF could only show symptoms on idle or at a static load (1600 RPM misfire / shudder you mention).

Worth a try, only going to cost you time and some cleaner fluid. If you can borrow a known good one that would be even better. Or log the MAF values in VCDS to confirm they are not sporadic.
 

wigandill

Registered User
Cheers for that Ill give it a whirl, may ring my local parts place now and fit it today if they have one on the shelf,
I did look.at the maf values earlier today on vcds
The box on the screen (which comes up with recommendations) stated on idle mine.should be around 190 to 300
Mine was sat at around 400

Does anyone know what they should read on these cars
 

wigandill

Registered User
Checked and changed about a week ago buddy no oil in the fuel at all.
Old filter had been on 6 months or so and the fuel coming out was still clean
 

A3pd170

Registered User
Good. My a3 was smoking bad like it was on fire changed fuel filter and oil and filter and it seemed better tandem pump next for me I think


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wigandill

Registered User
What colour was your smoke bud

I have read cam timing can have a affect on this
Alot of lads with the 170s have cured theres and also fixed rough and lumpy idles the same way but mine seems to tick over fine.
It does have a Slight miss if the revs are held at 1600ish rpm but go above and below and it disapears
Smokes very intermittent and is really winding me up.
All seemed to appear after the balance shaft failed so i replaced that, then fitted a hybrid and a large fmic, got it mapped when i arrived at the mappers he said i had a awefull vac leak, fixed that then the car was mapped and i left runs really well and pulls brilliantly just when coming to a stop at lights ect or in stop start traffic the smoke it kicks out is terrible.
Cam/torsion timing has been done on mine and had no effect on the issue
 

A3pd170

Registered User
Blue white only on idle tho and it kangaroos about 1500rpm if I put foot down hard just orderd aluminium manifold of eBay


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wigandill

Registered User
Yea mine is mainly on idle or when pulling away in traffic ect
If you boot.it in any gear when moving its very clean hardly any black smoke either
 

wigandill

Registered User
Duno if this helps
 

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Mario

Registered User
Seems to be a grey/white colour maybe with a blue tinge.

All seemed to appear after the balance shaft failed

So your balance shaft failed (leading to a total loss of oil pressure) and now you have smoke on idle with a blue tinge....screaming worn piston rings or valve seats to me!

Sounds like when you lost oil pressure as a result of your balance shaft failure it cause some metal on metal contact and damage which is now giving you a smoking problem and the fact it's grey with a blue tinge means it's burning oil.

Sorry to say, but after reading those 2 comments I no longer think this will be an cheap or easy fix.

Try doing a compression and leak down test to determine the state of the engine.
 

wigandill

Registered User
The thought of valve stem seals and piston rings has crossed my mind many times but id have thought it would have been constant, we had a truck in last week with a few fine scores in the rings on 2 pistons and that used to smoke constantly.
The engine did loose oil pressure but not for anymore than 10 seconds and it was shut of instantly and rolled onto my drive, i have seen a few of these driven for a while before with no oil pressure, wiped the turbos out but the engines have been ok once a new shaft was fitted and hex key.

It is really intermittent, today hardly any smoke, yesterday the same but Wednesday on the way home from work was appauling, cars behind leaving 3 or 4 cars lengths
 

Ianski68

Registered User
I am feeling your pain lol.......I don't think mine is as bad as yours but maybe. Still seems to do on every car journey. I don't think mine is to do with oil. Mine smells like burnt diesel, as apossed to oil but it's been a while since I fabled in car autos. I need for it to happen with someone in the know tomsee it really. If I book it in to a garage no doubt they will milk it for all it's worth ☹️☹️

No loss of power so just need to stop looking out the rear mirror lol..
 

Scarlin

Registered User
Hi I have had similar issues with my 170 BRD Avant its also been driving me mad for last few years !!.
I had all injectors and harness changed by audi about 3 years ago as one failed whilst on the autoban going through Germany . and that was prior to the recall for that model so had to fight for it with audi uk total nightmare !.
I ve had lot of issues since then lumpy idle grey blue smoking etc can even smell it in the car when car is stationary at lights .
. Ive also had car in and checked by audi a few times and had a injector with poor reading replaced . I have also changed the dpf sensor as heard that can cause it with the car trying to regenerate dpf continuously ... although not that
Ive decided to do the injector seals shortly as have now found oil contamination in the fuel tank so that explains the grey /blue smoke out the exhaust so nothing to do with the engine it seems
you should open up the fuel tank and lift the fuel tank pump etc out the and check for oil contamination in the diesel as that would explain all the above . if its not contaminated it will probably be the pump on engine I've been told but I m going to start with the injectors seals as kit was only £130

I m also needing to post and see if someone has a guide for removing and cleaning the fuel tank/pump etc out
don't know if there is an additive that can be put in with fuel to break up the oil sludge in tank without causing any damage to pump etc in tank
cheers Stephen
 
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