Technical Stilo JTD Knocking (pinking ???) on acceleration

[Davren]

Just got back from a 2 month, 4000 mile round trip to Corfu.

On the way back through Austria a noise started from the engine that sounded exactly like a petrol car pinking. It only happens when accelerating under load in high gear (just like a petrol car pinking).

As far as I know, diesels don't pink like this so any suggestions on what this could be would be welcome.

Dave.

 

[Argonought]

What about fuel consumption? - leaking injector :chin:

Presume you've tanked up with some quality diesel and you're not using a cheap engine oil

 

[Davren]

Average fuel consumption for most of the trip was 49 mpg. That includes about 800 miles of very minor roads in Corfu and about 50 miles of mountain passes over the Dolomites when the CN+ Sat-Nav threw a wobbly and refused to find a motorway.

I timed it to be empty in Luxembourg on the way back because diesel is only 88 Euro cents a litre there. I'm still using that fuel so haven't checked consumption since then.

I changed the oil before I went using GM (Vauxhall) branded fully synthetic. It's only used half a litre in 4000 miles.

Wouldn't a leaking injector throw up any fault codes? From the Lambda sensor for example.

Dave.

 

[Argonought]

Wouldn't a leaking injector throw up any fault codes? From the Lambda sensor for example.

I would have thought so - only guessing really - but 49mpg is not brilliant for a long run especially if yours is still standard map.

I think I've seen similar posts before about 'pinking' in the sub 1300rpm range but that doesn't explain why its just started to happen.

Might be EGR sticking a bit and causing a very weak mixture under load although would've expected you to notice the performance decrease :chin:

 

[mickbr71]

had the same on mine , turned out that it had a faulty injector which was low on pressure . cheers mick

 

[john55]

Classic symptoms of a worn injector.

 

[Davren]

After 8 months and 7,000 miles of this "pinking" noise, it seems I've finally fixed it.

Noise sounded as though it was comming from the front of the engine, so today I drove the car without the auxilliary belt (great fun with no PAS) and the noise was gone. I'd previously fitted a new belt and adjustable tensioner so decided to replace all the other pulleys one at a time. I already had a spare new crankshaft pulley so fitted that one first and no more noise.

Strange thing was, there was absolutely no wear in the old one. The rubber was completely intact and there was no play between the 2 metal parts of the pulley. The new pulley, however, has quite a lot of rotational play in the rubber between the 2 metal parts.

The new pulley is a modified one and, as the center of it is dished, needs 4 shorter RIBE bolts to fit it with. It's also £20 cheaper than the old one.

1 x 55208280 Pulley.... £80.90 incl. VAT
4 x 55215663 Bolts @.. £0.68 incl. VAT

There's also someone selling 8 of the new pulleys on eBay for £59 each + £8 Post here:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290411407740&ssPageName=STRK:MEWAX:IT