406oc.co.uk

About 2 and a half years ago my crankshaft pulley was changed at a pug dealer due to the annoying rattling, anyway i have notice that at high rpm between 2000-3000rpm it does it mainly in third i thought these new pulleys were fixed or is it another issue.

Happened on my last 406. You need a new set of injectors.

Anyway i can just get the reconditioned

My last Xsara HDi 90 always did this on full throttle, most noticably in third climbing steep hills. For want of a better description, it sounded like a petrol engine 'pinking'. Went quiet instantly at over 3000 RPM. I had the car for 100,000 miles & it's behaviour never varied, so I believe it was normal.
My guess is that the HDi runs so quietly & smoothly because of the pre & post injection of small quantities of fuel before and after the main 'bang', thus avoiding the massive cylinder pressure changes which cause the characteristic direct injection clatter, so beloved of VW owners I reckon the HDi process is quieter & smoother, but possibly compromises a little on out & out power. I think our engines revert to single injection under maximum load conditions, when you're less concerned about smoothness.

dogslife wrote:My last Xsara HDi 90 always did this on full throttle, most noticably in third climbing steep hills. For want of a better description, it sounded like a petrol engine 'pinking'. Went quiet instantly at over 3000 RPM. I had the car for 100,000 miles & it's behaviour never varied, so I believe it was normal.
My guess is that the HDi runs so quietly & smoothly because of the pre & post injection of small quantities of fuel before and after the main 'bang', thus avoiding the massive cylinder pressure changes which cause the characteristic direct injection clatter, so beloved of VW owners I reckon the HDi process is quieter & smoother, but possibly compromises a little on out & out power. I think our engines revert to single injection under maximum load conditions, when you're less concerned about smoothness.

Excellent reply Doggy

Mine always rattled but at 3000rpm when the third piston of the HP pump came in it went quiet instantly - again pointing to fuelling. It would be an interesting, expensive, exercise to get the injectors reconditioned just to see what we've all been missing out on (or not maybe) I've often wondered whether these Piezo injectors are only really good for say 80K before a refurb? hope not though but makes you wonder if you're really getting the best performance/economy all the time.

My old 306 HDI 90 did it, my current 406 HDI 110 does it.

Every hdi engine ive driven has done it. For some reason the noise must be amplified at the bulkhead area, because you sit in the passanger seat and let someone else drive, and its hardly noticable.

Also from outside the car, its barely audiable, everyone comments on how quiet my 406 when i drive off!

I think you can be in danger of developing rattle paranoia, i know i can hear the slightest of things that always sound "slightly different" every day.

Just keep the radio at a sensible volume, thats my solution, until something breaks anyway.