petrol sounds like a diesel any ideas?

[Longintooth]

[quote][That'd be a foolish investment on a tubby since they don't have the usual OBD facilities/quote]

Hi
Well I wasn't sure it had an OBD2 so the next best thing is a digital multimeter but some day a change of motor may justify getting hold of a scan tool now. However, the original post asked for ideas so here is my take on the subject - if the noise experienced on some examples lasted for 100,000 mile with no problem then it was not pinking that was being heard in that instant. A common problem with any modern engine using ECU control is that the Knock sensor is so sensitive it will pick up any metallic noise close to it - so for example, if the exhaust is rattling or some other attachment is loose then the ECU receives a signal and retards the engine when it does not need to, so many are getting poor performance and the unwary owner or untrained fitter will disregard such items as not relevant and spend lots of time and cash on diagnostics that are not necessary. Now it is still very important to ensure it is not pre-ignition that is being heard since it will not be tolerated by the engine - it will knacker the pistons and valve gear and in some cases the crankshaft big end bearings since the shock impulses are enough to increase the wear on these bits. My advice to some on this site is to start thinking outside the box. Absolutely no manufacturer would produce an engine without a foolproof method of controlling pre-ignition, so if it is pinking there's a fault somewhere. Elimination, elimination is the key.

[Alfamonk]

I'm not sure the knock sensor would react to an exhaust rubbing-noise.
I'm thinking along the lines of minor cambelt stretch and slippage over time resulting in the timing 'discrepancies'.
There's also the case that the lower compression-ratio of the turbo engine is more sensitive to petrol quality.
whatever, it's not a good sound to hear when you accelerate - history suggests that pinking = detonation = engine damage.

[mjb]

However, the original post asked for ideas so here is my take on the subject - if the noise experienced on some examples lasted for 100,000 mile with no problem then it was not pinking that was being heard in that instant.

My take is that it appears common enough to be written off as a 'characteristic' of the XU10J2TE. I'd be more inclined to start saving for the inevitable failing of fans, cv boots, radiator, blower fan and (if it's being over-boosted) a new turbo

[Welly]

Have you tried Super Unleaded?

[steve_earwig]

Have you tried Super Unleaded?

Special request going out to my man Welton

[Welly]

[Longintooth]

Hi
Well we seem to have a consensus on this one.
For anyone interested enough to check out the sensitivity of a good knock sensor try coupling up to a digital multimeter and tapping the area around it with a spanner you will see how the readings react. Then you will understand how important it is to make sure everything is tight. Even try how far away you can go before it does not react - you will be surprised.

[teamster1975]

Have you tried Super Unleaded?

Special request going out to my man Welton

Very good Steve
I was counting up how many times he'd said that earlier!

[mjb]

Well if anyone with a tubby and some spare dollah wants to try a new knock sensor, it's part number 594630 from the dealer for £37.39

[Longintooth]

Hi
To nail this one by simply using a more expensive fuel is not exactly good engineering or economic sense to be honest but if it stopped the noise it may be another way of proving you got a faulty sensor - if it is pre-ignition the knock sensor should do the job otherwise you could be masking the problem. For those who ran their motors with a rattle then they should consider if the timing was always retarded by it and losing performance unnecessarily. I would always like to test for a fault rather than simply changing a part to see - a very expensive way to diagnose a fault and many so called technicians use this method all the time vis a vi the Turbo that was changed but did not cure the fault. What happened to good old technical knowledge?

[Welly]

Yeah it's the Jacket, second on the left....ta, is that the door?

[teamster1975]

I couldn't afford to run mine on that 24Ct liquid gold Welly!
On the plus side Morissons unleaded has just dropped to 113.9

I don't understand enough about how the timing works on electronic ignition but Longintooth's thinking does seem logical.

[steve_earwig]

Well, you see, the ecu's got this kind of map and from what the sensurs are sayin (frotul pozishun, injin spid, nok senzur, ekshiterer) stuffs out electickery in pulsies frew an amplyfrier to the koiawls. Innit.

Knock sensor=pizza electrik, jus lik an fag lita.

[mjb]

Last time I was at a petrol station I put £90 of that stuff in (as opposed to their standard stuff). Amazingly it's picked up my economy driving to work from 19mpg average to about 22. Going to do a long motorway run this afternoon which'll be interesting

[steve_earwig]

I stuffed about 50 squids worth of eurodiesel in mine the other day. This is the garage down towards the motorway where it's more expensive but, according to the latest testing, their fuels are the cleanest, so I thought I'd try theirs for a while to see if it does anything for my economy and maybe quietens down my injectors. When I got there normal diesel was 9.90Kn (= £1.08) and the euro stuff was 9.99 (=£1.09) so I thought in for a penny...

I've done about 300km now and the injectors are just the same It does seem a bit smoother tho.