Vrs hesitation - fly by wire problem?

[izard-industries]

Hi all, I've got a mk1 vrs. 103k, baileys dump valve, new plugs, serviced, new thermostat and coolant temp sensor.

I get quite bad cold running issues, it splutters quite badly until it's warm the it improves but is still noticeable. When it's warm, if I give it 1/4 throttle in 2nd from 1500rpm it will pull you can feel it boost then its as if I lift off the throttle. Doesn't do it all the time

I've searched around and found 2 split breathers and replaced them, can't see any other noticeable things wrong.

Could there be a communication issue between the throttle pedal and throttle body?

I know this is a real common problem but seems like no one has actually properly cured it!

Joe

[Philip Coulson]

Could be a voltage problem. Try cleaning the earth points under the battery.

[AshleyHart]

Have you got a wide band sensor nocking about or a mate with one?

I say this because this was the same problem I had with my c20let corsa as it was not fuelling right... it was the lambda sensor causing the issue.

[pauldazzle]

Always worth cleaning the throttle body.

Was the coolant temp sensor genuine VAG?

[pauldazzle]

Also check with Skoda to see if your car is covered by VAG coilpack TSB.

[izard-industries]

Sensor was genuine one, haven't got a wideband. I've got a snap on scanner and came up with

Secondary air incorrect flow

And I think bank 1 too rich or something like that. I'll take the throttle body off later clean it out and rescan for codes!!

[pauldazzle]

Secondary air intake failure is common usually caused by the rivets on the SAI pump housing failing or the SAI pipes coming off or splitting.

http://uk-mkivs.net/forums/t/141240.aspx

Bank 1 too rich could be a number of things. A dodgy Coolant temp sensor causing the ECU to fuel incorrectly, Lambda sensor or split boost/vacuum pipes would be my first suspects.

The throttle body is prone to getting gunked up on the inlet manifold side of the TB butterfly flap. N.B. On DBW TB do not force the butterfly flap open to clean it, remove the TB with it plugged in & with the ignition on wedge the accelerator down so the butterfly flap stays open for cleaning. When you reinstall it (ignition off) turn the ignition back on & you should hear whistling from the TB which is the TB self aligning, wait until the whistle stops, start the engine & go for a run using as many throttle postitions as possible. Over a few driving cycles the TB will self adapt. However if you have access to VCDS you can perform a TB adaptation to re-adapt the TB in a few seconds.

Edited 2 November, 2013 by pauldazzle

[pauldazzle]

Don't forget to see if your car is covered by the VAG coilpack recall/TSB too.

[izard-industries]

Do I just go into skoda and ask if its covered?

I removed the throttle body and cleaned it out, wasn't all that dirty just a bit oily and brown staining no real thick deposits. I scanned for codes as I've got a engine light on came back with these:

P0411 secondary air intake system faulty flow

P1432 secondary air control valve n113 intermittent fault

P0300 misfire

P0301 cylinder 1 misfire

P0303 cylinder 3 misfire

Any ideas lol!?!

[Shadows Entity]

Also bailey dump valve will probably leak boost need a recirculation/diverter valve i.e. forge 007, 008 or splitter

[pauldazzle]

SAI faults as decribed in the previous link & sounds like the N113 valve has failed

Misfires = usually coilpacks failing.

[pauldazzle]

As above Bailey DV's usually cause problems on VAG 1.8T's too.

[izard-industries]

Sorry I meant forge 007!

[izard-industries]

Soo just a update after cleaning out the throttle body all seems ok! Fingers crossed!

Cheers for all the help

[Shadows Entity]

Yea mine felt like it was at stalling point on first start up when cold and literally cleaning the throttle body fixed it

[vrsmark]

Well....I have to say,mines been misfiring on cyl3 and occasionally cyl4 for a while now.

I'm a bit stumped as to what the cause is to be honest.

I've changed all 4 coilpacks then it went away for a couple of weeks,then started to misfire again!

Checked the plugs and they are fine,even swapped the plugs around in the cylinders and rescanned it,no difference!

Throttle body is clean.

Wiring is good,gave it all a good once over today.

I'm starting to think its the CTS! ;-)

[izard-industries]

Have you cleaned it or does it just look clean? Mine was pretty clean and even after I cleaned it, it sorted it! Don't forget to clean the air temp sensor aswell. (The first sensor after the throttle body)