8p semi rough idle issue, advice needed!

[SIR_LOIN]

Hi all once again,

 

So after many many hours of researching and with my face stuck in my engine bay, im coming to the end of my limited Audi engine knowledge and im hoping, if not praying that someone here might be able to help.

 

My 8p runs beautifully out on the road, but at stops or while its idling it just doesnt feel right, its not a really bad shake but it definitely sounds like some sort of a misfire.

 

So much investigation has gone into trying to find the culprit, I've replaced plugs, leads, cleaned the throttle body/manifold/all piping.

Checked for air leaks, replaced perished pipes, had it compression tested, valves checked, had it a mechanic who told me it needed a remap (godshite), had it to audi who couldn't tell me with their diagnostics and wanted to charge me an arm and a leg for further investigation.

 

I was told it could be the egr valve or the map sensor, changed both to new ones and still the same....

 

So today I go at it again, checking everything that I can and cleaning what I can and ran it on VCDS diagnostics,

Im now getting an error code (16784) for my (wait for it), egr valve!! Which I never had before, typical right?

 

I've also got a fresh one which is obviously linked to the other:

(16891) 'idle control system rpm, higher then expected '

Both are intermittent though.

 

List of things done already over the past couple of days

 

New brake light switch

New egr valve

New ignition leads

New ignition coil

New oil pressure sensor

 

With a bit of reading up i read it could possibly be the PCV/PVR/Crankcase Breather Valve, which i have purchased today but have no idea where it is located on my 2004 8p engine so if anyone can help there please do!!

 

Heres a link for reference:

https://www.micksgarage.com/d/crankcase-breather-parts/audi/audi-a3/a3-2003-to-2012/1-6-102-1595/products

 

Was also told its possibly my crankshaft sensor but Im hesitant as its not showing up on VCDS as faulty...

Im also noticing it has a light, almost white smoke coming from my exhaust at revs above 3000 rpm from idle.

 

Sorry for the essay but please can anyone share some light or had similar problems?

My heart is broken at this stage and I've got an 800kms trip to cover next week 

 

Tyia and much love

 

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MOV_0247.mp4

[Trevor]

I would start by running some strong cleaner through the fuel system, remove the EGR and clean/delete and then look at the obvious stuff again, you may have missed something (it happens)

p.s. all of the above costs very little money and is where I would start if I were sorting the fault.

[SIR_LOIN]

2 hours ago, Trevor said:

I would start by running some strong cleaner through the fuel system, remove the EGR and clean/delete and then look at the obvious stuff again, you may have missed something (it happens)

p.s. all of the above costs very little money and is where I would start if I were sorting the fault.

Hey Trevor and thanks for the reply, thought it might be just you and me in here ;)

Any recommendations on a good fuel system cleaner?

Ive been adding Redex to the last couple of fill ups to give the injectors a little clean, noticing the difference top end but with revs below 2k its the very same.
Went out yesterday and removed the egr valve again, checked all pipes and cleaned with carb cleaner once again, checked the gaskets etc and everything seems to be fine.
Its very frustrating at this point, almost ready to throw in the towel and get it to a mechanic :(

[dannyogrady]

I have the same problem with my 2006 1.6 petrol! It's doing my head in! I'll be following this topic in hope of finding an answer 

[SIR_LOIN]

10 minutes ago, dannyogrady said:

I have the same problem with my 2006 1.6 petrol! It's doing my head in! I'll be following this topic in hope of finding an answer 

Its a nightmare right?

For some reason whatever research ive been doing, (and what little im getting back), it seems to be only the 1.6 petrols that have this issues, is your a mk2 also or mk3?

Noticed today also after doing yet another egr clean etc that as im letting off the throttle and the car is coming back down in rpm's in lower gears the car has a little stutter :(
With the amount its cost me so far i just cannot let this problem beat me lol


 

[Dan3222]

I am still getting used the engine names but I think the 8P is a petrol?

If you are getting white smoke then the only cause can really be water ingress. (I am happy to be corrected here btw). Is your water level going down at all? Does you car have an EGR cooler? These seem to be prone to leak on VAG engines.

When your engine is warm, but switched off. Carefully open the coolant expansion tank, you don't need to remove the lid fully, just release some pressure. If you see loads of bubbles rushing into the tank then it's a good sign that the head gasket has gone or the head has cracked!

Redex is a good enough injector cleaner, try a double dose in a half tank and drive it for a few miles. Then fill it up and drive as normal.

 

keep us updated!

 

[SIR_LOIN]

1 minute ago, Dan3222 said:

I am still getting used the engine names but I think the 8P is a petrol?

If you are getting white smoke then the only cause can really be water ingress. (I am happy to be corrected here btw). Is your water level going down at all? Does you car have an EGR cooler? These seem to be prone to leak on VAG engines.

When your engine is warm, but switched off. Carefully open the coolant expansion tank, you don't need to remove the lid fully, just release some pressure. If you see loads of bubbles rushing into the tank then it's a good sign that the head gasket has gone or the head has cracked!

Redex is a good enough injector cleaner, try a double dose in a half tank and drive it for a few miles. Then fill it up and drive as normal.

 

keep us updated!

 

The 8p is the Mk2 my friend, couple of engine types but the 1.6 petrol is the bgu engine code.
The white smoke seems to have died down, i put it down to the new egr valve just going in, (that and i found a small crack in the oil pump hosing which has since been replaced)
Never really had an issue with smoke prior to the swap :(

Dont think we have a cooler with this engine, just the valve and the piping to the exhaust / throttle body so that should rule that out.
Il check that expansion tank test in about 30 mins, just trying to drag the missus out of the shopping centre lol.
Lets pray to the 4 ring gods its not the head, although im really not seeing any symptoms.

Il let you know withing the hour with the expansion test, and guys, much love, your input into this thread will guarantee your ticket into the pearly gates once we all get there :)

[dannyogrady]

On 7/3/2017 at 6:46 PM, SIR_LOIN said:

Its a nightmare right?

For some reason whatever research ive been doing, (and what little im getting back), it seems to be only the 1.6 petrols that have this issues, is your a mk2 also or mk3?

Noticed today also after doing yet another egr clean etc that as im letting off the throttle and the car is coming back down in rpm's in lower gears the car has a little stutter :(
With the amount its cost me so far i just cannot let this problem beat me lol


 

Hello mate, have you found an answer for this yet? 

 

I read somewhere that a guy had the same problem he changed the EGR and that solved it! obviously not cheapest of things for just checking to see if it changes anything but i suppose thats the gamble 

[Rob82DZL]

Hi mate, not seen a reply to whether you've got it sort or not but from reading through the thread I've got another couple of thing you can check.

Check the throttle body for a ring of carbon and it doesen't have which can cause it to almost stick shut when slowing down.

Another possiblity with the throttle body is if it's solonide operated while you can see it get someone to turn the ignition on (but not start it) and you should see it open a very minuet fraction.

One other thing, not to sound daft but when you changed the plugs did you gap them correctly or put them in straight out the box? Even from new the plugs need to be correctly gaped with feeler gauges.

And one last posibility could be the throtte potenciometer in the accelerator pedal but you need to find out what the resistances are ment to be at different throttle opsition before reading with a multimeter.

Hope some of this helps 😊.

[Iangibb96]

Anyone get to the bottom of this? 

[Magnet]

Hello Ian,

Thanks for being in touch. 

Do you have the same issue? 

If so, can I suggest you start a new thread - better than tagging on to a 3 year old one. 

Kind regards,

Gareth.