Hello everyone. Thanks in advance to anyone that reads and has feedback

 

I have a 60 plate Octavia Estate with a 1.4 TSI "CAXA" engine and I have 70K on the clock. I normally hear a bit of rattling when the engine is pulling gently up hill around 2000RPM. Occasionally (not all the time) this culminates in a much more severe metallic clacking noise. Always seems to be when the engine is hot and pulling up a hill. (not labouring though)

I have managed to catch this on my dash cam here:  (noise comes in at 0:02 and sounds louder in person)

I noticed a bit of light smoke, like running rich when I looked in the rear view mirror too. It only did this as the noise happened. Otherwise the car runs fine. No loss of power, no warnings, smooth running (apart from mentioned noises) and starts fine. I like the car but the noise is filling me with dread that something is going to go horrendously wrong.

The car has been to the Skoda dealer twice and they havent been able to reproduce the fault exactly although the second time they suggest it could be the timing chain, but cant guarentee it'll fix the noise. They suggested that if it was bad, the noise would be more prounced all the time and I should just monitor it.

 

I am thinking that the car is worth to taking the hit on a new timing chain as it'll cost a lot more to source a new car or donor engine if something goes pop. At least it'd be peace of mind that that chains are in good condition. I am worried that it could be something other than the timing chain though... like VVT, injectors or some other kind of damage. What about the smoke? would timing cause that?

 

Sorry for the essay. I don't have a lot of money to chuck at expensive faults like this so need to be fairly sure I'm trying to fix the right thing! I'm wondering if its worth getting a compression test and a camera examination of the combustion chambers just to see if this gives any more clues as to the general health of the engine.

 

Thanks,

 

Mike

Describing it as light smoke was it not much, or is it a colour reference?

was the smoke - white or blue?

 

 

Hi mac11irl,

 

Difficult to say for sure was it wasnt a thick cloud of smoke, just barely visible. It didnt look white, more a dark greyish colour like you get from excess fuel. The exhaust pipe doesnt look overly dirty or contaminated with anything.

Pinking.

Hi J.R.

 

Thanks for the feedback, that is the type of noise that it is.

I guess the question is, could a stretched timing chain cause that?  or is it more likely to be sensor/VVT related?

It's odd how the ECU isn't picking up any knocking from detonation.

 

Just for the record I started running Tesco momentum 99 or Shell V Power unleaded (when I can get it) to see if a higher quality fuel made a difference. It hasn't stopped the issue but I still run higher RON fuel as the economy is a bit better.

 

I was up to speed on negine controls, ECU's & maps 30 years ago but the world has moved on.

 

Back then the engine would have had a piezo knock sensor on the cylinder head which would retard the ignition timing instantly without you ever hearing or feeling it, they would try to run the engine with as much advance as they could while remaining just under the detonation point, driving up a hill in a high gear with WOT is when pinking would occur.

 

 

Maybe the knock sensor has failed, a connection or is disconnected, do a VCDS scan.

All modern petrol engines run crankshaft position, camshaft position and knock sensors so pinking isn't heard off these days, not to say it doesn't happen. as J.R has said a VCDS scan is a must to find the correct fault. if one if these sensors is at fault the ecu will try to compensate using the other two, if the fault is bad enough it should bring up the engine management light.

Thanks for the feedback guys. The annoying thing is that I don't see any lights on the dash. A fault code would actually give me something to go on.

The only thing I had to do previously was free off a sticky turbo wastegate as I could feel loss of power from that. In all other regards, the car drives perfectly.

I'm kind of thinking that the timing chain will need doing regardless. It seems that I won't get much help diagnosing this issue until that is done. It will at least be a bit of peace of mind knowing that I don't have an engine that's likely to self-distruct from its best known flaw.