Intermittent Idle

Good Afternoon Ladies and gents!

I’m having a few problems with my 53 Plate Octavia VRS Hatchback,

Engine Code – AUQ

Recently the problem seems to be getting worse and worse,

When I first start the car and “Accelerate†up the street, there is no power, as if its running on 2 Cylinders, sometimes I can give it a bit more gas with the clutch in and this seems to cure the problem for that journey, and I drive on no problem.

However now I can hear the engine starting to labour, but never stall. Also when coming out of gear, the engine rev’s seem to drop a bit too sharply for my liking.

I’ve got a VAG COM Diagnostic tool, and have come up with the following Error Codes

16795

17705

16486

I’m aware of these codes descriptions, however I’m not quite sure how to fix them.

if this had been an older car, I’d be changing the plugs, checking the fuel filter.

Non of these has been done in the year that I’ve owned the car, but I don’t want to replace them with no effect.

Anyone got any ideas on where to start ?

A job that I did do last year was to replace the “Y†Pipe on the top of the engine with the Silicone variant, however I haven’t changed the other part that came. (So that might be first POC)

I’ve also never had a Turbo car before, so although I’m pretty technically minded, has anyone got a picture of an engine bay/guide on what to do?

Many Thanks

Iain T

Another little thing that might or might not be related,

The Engine never really gets up to 90 Deg, like other cars i've had, and the exhaust is always giving out vapour, even when the cars been running for 30 mins or more.

16795 - something to do with your secondary air system, get underneath the car and there is a black plastic pump thing near the front of the engine on the drivers side, it should have two plastic hoses going into it and a multiplug. Check these are all secure, and follow the hoses and check for any leaks all along their length and at any joins. Its always worth waiting a minute or so after starting a VRS from cold before pulling away as this gives the secondary air system a chance to do its job.

17705 - This could be an old stored fault code from when you replaced the Y pipe and just needs to be cleared. Get all the fault codes cleared and if this one comes back you have another split pipe or leaking valve in the turbo system somewhere (have a look at RobClubleys recent diagram of all the hoses and valves on the AUQ engine). It's also worth giving it a throttle body clean as this is very cheap and quick to do and can sometimes sort out a 17705 error.

16486 - something to do with your Mass Air Flow which would explain why it's idling badly if it's not sure how much air is coming in. Try unplugging the MAF and running without it and if the car runs better then your MAF is goosed and needs replacing. The MAF plug is on the top of the large hose between the air filter box and the turbo which is behind the back of the engine.

The engine never getting up to 90 degrees suggests a faulty thermostat (stuck open, or never closing properly), you might see a 17704 fault code with this in future.

Edited 10 March, 201016 yr by chicken_eyebrow

as well as what Chicken said the idle could be the lower hose that you didn't replace or the small vac line that goes from the PCV valve to the inlet manifold, also check the vac lines to the DV. A TB clean usually helps as well

I did a boost leak test today and found that the small S hose that goes from the PCV small valve to the inlet manifold is broken when exiting the PCV valve at the 90 degree turn. Do you guys know the code for it? There was a picture of the PCV system off the car and annotated with codes, but I can't seem to find it.

I bought one the other day and also added an extra check valve into it. the pipe is 06A 103 221 BK and there are some pictures in this thread http://briskoda.net/forums/topic/152431-busy-day-for-lots-of-us-by-the-looks-of-things-d/page__p__1894961__fromsearch__1entry1894961

Thanks a lot.

I've also got a question about the boost leak test. I did this by pumping pressurized air into the TIP. The mentioned hose was hissing, but once I covered that up with my fingers I could also hear another his from around the TIP/Turbo part of the engine. I felt around a little bit for it but couldn't really find it...almost sounded like it was coming from inside somewhere. Is this normal? Where is it coming from? Should I keep looking for a leak there also? Note: the hose leading to the big black round pancake valved on the TIP was clamped. Offtopic: what DOES this valve do?

Edited 12 March, 201016 yr by jmf

that is the valve for the crank case gases often refered to as the "hockey puck valve" I think the idea is that under VAC the crank gases go through the S pipe and under boost they go through the hockey puck. I dont think it is a check valve more of a flow limiting valve as it does not close off completely

Thank you for your quick replies

RIght, the day of car fixing and tinkering has arrived, engine cover off!

16795 - something to do with your secondary air system, get underneath the car and there is a black plastic pump thing near the front of the engine on the drivers side, it should have two plastic hoses going into it and a multiplug. Check these are all secure, and follow the hoses and check for any leaks all along their length and at any joins. Its always worth waiting a minute or so after starting a VRS from cold before pulling away as this gives the secondary air system a chance to do its job.

- Ok, Secondary Air System. Not much of a clue what that means but should be able to find the pipes given your description

17705 - This could be an old stored fault code from when you replaced the Y pipe and just needs to be cleared. Get all the fault codes cleared and if this one comes back you have another split pipe or leaking valve in the turbo system somewhere (have a look at RobClubleys recent diagram of all the hoses and valves on the AUQ engine). It's also worth giving it a throttle body clean as this is very cheap and quick to do and can sometimes sort out a 17705 error.

Throttle body i won't be able to do as i don't have a new gasket, and i don't know if i can do the TB reset with the Code Reader i've got (It resets code, but i think thats it)

16486 - something to do with your Mass Air Flow which would explain why it's idling badly if it's not sure how much air is coming in. Try unplugging the MAF and running without it and if the car runs better then your MAF is goosed and needs replacing. The MAF plug is on the top of the large hose between the air filter box and the turbo which is behind the back of the engine.

Mass Air Flow ? Sounds like a computer game I'll have a hunt for this.

Anyone any idea where the 2nd Pipe goes ?

http://s973.photobucket.com/albums/ae219/tommytp85/?action=view&current=IMG_0334.jpg

Many Thanks ladies and gents

Throttle body i won't be able to do as i don't have a new gasket, and i don't know if i can do the TB reset with the Code Reader i've got (It resets code, but i think thats it)

You can take the hose off and clean the outer part of it, if you turn the ignition to position 1 and have a helper to put their foot on the throttle so the throttle plate opens you can clean part of the inside of it as well, although as you say, you need to have a new gasket to be able to take it apart and clean it thoroughly. You only need to reset it if you unplug the big plug from the side of it.

Mass Air Flow ? Sounds like a computer game I'll have a hunt for this.

The multiplug for the MAF is ringed in red in this pic:

I've got a feeling the other pipe you've got there is to replace one of the ones underneath the inlet manifold. You'll have to remove the metal plate around the dipstick to be able to get to those hoses, or come at them from under the car.

Edited 13 March, 201016 yr by chicken_eyebrow

that is the pipe that goes from under the inlet manifold down to the PCV Check valve coming off the crank case breather. you actually have it in almost the right position - although just under the manifold would be better though also worth putting in the extra check valve as the PCV one is a bit weak and gets clogged up quite bad.

here is the link for the SAI fix from UKmkiv's http://uk-mkivs.net/forums/p/141240/940861.aspx#940861 it is a fairly easy job as well.

HTH

Thanks for everyones help today!

Just spent the fully day on the car,

Air Filter (Clogged up, hoping this was effecting the MAF reading)

Oil Change (For good measure, had the car for a year nad 6000 and not done it)

Spark Plugs - They had a 1.0mm Gap! REcommended 0.7mm

and that BLASTED 2nd Pipe, got it done, however i've snapped the Dipstick holder in the process :( ( it was brittle )

So thats a job for next weekend,

So thanks for all your help guys and i'll let you know if any of the fault codes come back!

I've taken it for a quick spin with the engine warm, and no problems so far, the test it the cold engine start though

I had the same 17705 problem a few weeks ago, changed the pipe to the right of the dipstick you just have, and it`s like a new car. Cold take off is superb, no hesitation, and car has better pickup all round.

Just to let everyone know,

The car ins't the best on Startup, but i think this is secondary air thing related (Can live with this for now)

The car drives like a dream since changing sparks and changing those cables, even if i did snap the dipstick holder :(

Well I changed the small PCV hose and the flickering idle is still there. Boost leak test shows no audible leaks. Any other ideas?

Well I changed the small PCV hose and the flickering idle is still there. Boost leak test shows no audible leaks. Any other ideas?

Have you actually had the MAF out and cleaned it by spraying with IPA (iso propyl alcohol aka electrical switch cleaner)?

3 weeks ago I started to get lumpy idle on my 51 reg vrs with the following codes: 17705, 17545, 16393, 16514.

I cleaned the TB first (as per Chicken's instructions, then the MAF, got no relief, then cleared the codes and all was well. For the MAF, once off I sprayed it directly, then put it in a zip placcy bag and shook it up with sprayed liquid, left for 5 mins then 2 mins with the hair dryer and back on. (Better instructions on MAF cleaning are here somewhere. They say to leave overnight but i just used the hair dryer.)

It seems to me that when the air/fuel settings get out of kilter it can produce several seemingly disparate and unconnected error codes. The Y breather pipe I replaced about 18 months ago and "under manifold pipe" last June (both standard VW parts) and i don't think I have any other leaks. I assume the above codes were probably down to the MAF reading wrongly, prob made worse by the throttle being gunked up a bit.

The erratic idle which I had was one you could feel as much as hear, it would dip down every couple of secs from about 750 to 500rpm. It seemed to happen particularly after a run where you were also aware of some hesitation and power loss when pottling back home on local roads after leaving the motorway, HTH.

The MAF is new (i mean, about 8 months old), but when I changed it there was no improvement in the symptoms. Otherwise the car drives fine, even perfectly I dare say.

And yea, I can feel the flickering too :(

The MAF is new (i mean, about 8 months old), but when I changed it there was no improvement in the symptoms. Otherwise the car drives fine, even perfectly I dare say.

And yea, I can feel the flickering too :(

This may be my superstition, but when I did my cleaning of the TB and took it for a drive, there was no change, then I had the MAF off and cleaned it, still no change. It as only when I hooked up VAGCOM and saw I still had those fault codes and cleared them, that the problem went away. Driving the car and ignition on/foff a few times ought to have the same effect: I assume the computer collects data over a period of time and averages it, so it may take some time for any faulty readings to clear out.

This also leads to the situation where a dealer can claim to have fixed a problem, reset the code(s), then it re-appears after a week (which happened to me with Winchester Skoda who failed to find the split PCV hose and just cleared the codes and charged me 100 quid for the privilidge. This prompted me to get a VAGCOM cable, get the code and spend 10 mins on Briskoda and locate/fix the problem).

But you seem to have tried everything so it's a bit of a mystery.

Hi,

 

I hope I'm not jumping in on someone's topic, but I have a similar running problem with my 03 VRS.

 

I've just bought a replacement Crank Vent breather PCV Valve and am waiting for it to arrive. Can anyone tell me where it fits please? I've researched it (and got a Haynes manual) but can only find reference to newer models, not mine (Mine's a MK1 VRS).

 

Thanks?!