Check Engine Light, juddering and low boost

[Nautilus]

Today, while driving on the highway, the Check Engine Light began to flick. Car seemed to vibrate (like in older engines when a sparkplug didn't fire) and boost did not get over 0.3bar regardless of rpm and throttle.

While staying at stoplights, the CEL remained on, driving a bit quicker it flickered or got off for a few seconds.

Pulled the MAF and checked, no signs of damage or gunk. Wiped gently with a bit of alcohol and fitted back again. Pulled out the Forge DV, checked it, greased(very little) the piston. Checked the throttle plate (a bit of oily gunk) and wiped.

Car judders, has barely any power adn boost doesn't get over 0.3-0.4bar despite vigorous efforts with the throttle.

There will be a diagnose done at the dealer next week.

What should be the most likely cause, so that I don't get panic attack when the dealer tells the result?...

Thank you,

~Nautilus

PS checked also with MAF disconnected, engine running changed very little and symptoms were the same

 

[B1NCC 1.8T]

Sounds like a possible coil pack failure, this fault should show up on the diagnostic machine and it will tell you what cylinder its miss firing on.
Coil packs are a very common problem on the 1.8T engine

 

[slim20vt]

sounds like boost leak? is is the car smoking black? if so defentley,boost leak!,or turbo could be gone,or waste gate! is stuck! you can buy your own ecu fault clearer on ebay about £40 under( seat diagnostics) good luck

 

[Nautilus]

It doesn't smoke

It judders not only under boost, but also at idle. Most judder is while pushing the throttle, once above 3000rpm decreases

CEL stays on at idle and low rpm, flickers at high rpm

Later Edit: when idling with cold engine it also makes a strange duff-duff-duff noise from the end of the engine which is closest to gearbox. This has happened prevoiusly, weeks ago, in cold mornings, when it juddered and did this sound as well, but CEL did not come on and after 1 minute of warmup everything had been fine

~Nautilus

 

[jaime]

I would tend to agree with B1NCC 18T, it sounds like a coil pack failure. I had mine go and I had sinilar symptoms. Didn't know what it was at first, called the RAC and voila, coil pack failure. It's gone on me since then so now I do them myself. It's quite simple to do. If you need advice, let me know and I can "talk" you through changing them. You might even find a giude on here...

Hope it helps!

 

[Nautilus]

Had no time to get it to any workshop, but pulled the wire from each coil pack. Engine running does not change at the second coil from the cambelt side.

CEL is now on all the time

~Nautilus

 

[andycupra]

definately coil pack and seems you know which one too
£25-30 for original parts all sorted. less at GSF etc.
prise up with flat srew driver a little, pull off electric lead. remove the coil pack.
Check spark plug isnt loose or anything silly like that.
Replace with new one.
push almost fully down, re-connect electrical plug.
then push down onto spark plug fully.

job done.

 

[Nautilus]

Does the CEL come off by itself upon chnage or is the diagnose still needed to clear the error code?...

~Nautilus

 

[DPJ]

Does the CEL come off by itself upon chnage or is the diagnose still needed to clear the error code?...

~Nautilus

It'll come off on it's own, but the code still needs clearing.

 

[neenor]

look on an auction site...got 4 for 55 delivered and they work fine...

 

[Nautilus]

Went to workshop today, diagnosed, changed the coil pack, changed oil and air filter, fitted Forge quick shifter (which was a bit disappointing). Case closed, thank you all

~Nautilus

 

[Nautilus]

Case not closed yet unfortunately

After a few miles of driving (everything fine, engine at full strength, boost, no judders) CEL comes on again. Engine still runs great. Went to dealer, diagnosed, error was "Ignition, cylinder #2, open circuit". Cleared the code, appeared again and again. Moved the coil on cylinder #1, error came with it. Both plugs fired, they were light tan in color. CEL came off, yet came on after another few miles of driving. Still running nearly 100% perfect, but with CEL on... they didn't know what to say, just that coil pack is not original and not recognized by the ECU, the light may stay on, or come off by itself in the future, and I shouldn't be worried as long as engine runs well.

There were no other errors recorded (VAS 5052 diagnostic computer)

~Nautilus

 

[Nautilus]

Tested a few minutes ago, up to 180 km/h on a deserted highway. Runs well, seems even better than before when all 4 coil were "good", but CEL still on. Guess I'll have to buy a VAG coil and keep the aftermarket replacement as a spare in the boot

~Nautilus