DS3 1.6 VTi Dstyle Plus - Engine Pinking

[Phil H]

On a cold engine and light throttle, my DS3 engine pinks/knocks - ie is firing before piston reaches top dead centre. I was under the impression that with electronic ignition, this wouldn't occur, but alas it does on mine.
Anyone else have any experience of this? It's done it since new and it's not a major issue, but seems to be getting worse on these colder mornings.

Does anyone know what the resolution maybe? Car is in for a service soon and I bet it won't be covered by warranty. Not like it can go on the Krypton Tuner (sorry showing my age there)!!!

[Bigfeet]

The noise you describe is quite normally for a VTi engine, once it warms up the sound will trail off.

[lfcrule1972]

I think WTF mentioned noises like this with her previous DS3 that was also a 120Vti...

[Sparky ds3]

My vti sounds like a diesel when started from cold i think they all sound like this after its got a couple of Thousand miles under its belt. Once warmed up its really quiet [emoji106]

Mark

[Bryn]

Sounding like a diesel when cold (especially when idling) and pinking, pre-ignition or knocking (all different names for the same thing) are not the same. Mine has always done the diesely thing and I gather its normal for these engines.

More recently, it has taken to doing the other thing as well. It's difficult to describe the sound but, if you hear it, you recognise it. Any acceleration, especially up hill or otherwise under load, makes it happen.

I had been going to get around to taking it to my local Citroen garage before the cold weather, as it had been getting worse. However, it seems to have stopped doing it! Co-incidentally (probably not!) the temperature gauge is now working again. Until recently, it has stubbornly refused to move above 1 bar.

Normal service has now been resumed - it moves fairly quickly up to half-way and then stays there as if glued in place. And, fingers crossed, the pinking when cold issue has gone away, too.

[Sparky ds3]

More recently, it has taken to doing the other thing as well. It's difficult to describe the sound but, if you hear it, you recognise it. Any acceleration, especially up hill or otherwise under load, makes it happen.

Mines makes this strange sound to when under load from about 5 mins from cold

[Chris_Blue]

Be nice to understand Czars take on this
Ive a THP and (usually in the winter) i get the diesel sound for a minit or 2, and guess that its the oil drained out from engine and parts etc etc (Read an article on it once) and that the oil needs to recirculate to the top of the engine and be evenly distributed before the noise will go. Obvs as its colder in the winter, and the oil viscosity is heavier, it would take longer for the oil to heat up and evenly distribute, and thats so long as the oil pump is good to go. Altho the counter argument is the oil is heavier it will stick to engine parts more easy. Thats why theres different grade/ heaviness of oils. But if the engine has been left for hours to go cold, the oil would have all dropped into the sump as it was hot when the engine was switched off, would it not?

So- 2 minutes warm up standing, minimum, and not above 2000 revs till mid temp on gauge reached

As for the pinking, thought that were the pistons not quite aligning with the cylinders, and trying to come up when combustion is pushing them down (As OP says) and that was due to timing, (For whatever reason: Chain stretch?) or incorrect burn in the combustion chamber (Pre-ignition) which on a THP is contributed too with carbonised valves, due to some of the carbonisation getting into the combustion chamber.

Frequent oil changes (Every 6k) and decent fuel is as far as Ive got. Oh.... and as per my other thread, get rid of as much heat as you can out the bay for Racings and THPers at least. Got to make sense.

Anyone tried a more viscous oil- my son in law is a mechanic, and reckons the oil (at least in the THP) used is quite thin and thought it should be thicker.

[DaveB]

Pinking/preignition/knock, call it what you will, is caused by the mixture being ignited too early. On a modern engine there should be a knock sensor (maybe more than one) which will detect knock & retard the ignition as required. I would assume that the ECU will normally retard the ignition for a cold start, but that will only be a base value & the knock sensor reading should fine-tune it.

In a hot engine it can also be caused by carbon deposits in the cylinder getting hot & igniting the mixture.

My 120VTi has never shown any signs of pinking.

Mechanical noise at start-up can be caused by a slow build-up of pressure to hydraulic tappets, valve timing actuators,etc - Alfa TwinSpark Variators were notorious for causing a "diesel" sound.

[Phil H]

I'm glad I'm not alone then. Yes I was thinking a knock sensor would have prevented it.