Ok where to start? bought car 3 months ago 99mdl with 160,000km on the clock.
Ran good for 2 months then.......

Engine developed a slight to moderate Pinging under load at about 1/4 throttle onwards through the rev range.

I thought Possibly Fouled Plugs - bought new set changed them and same problem.
I isolated the pinging to one cylinder only which is the third from the front on Drivers side (remembering im in Australia) I dropped the Spark Lead off the plug and it noticably ran on 7 cyls but didnt ping, put lead back on runs on 8 but pings.

Thought bad fuel? ran 3 tanks of PRemium 98 octane, 2 bottles of octane booster, 2 bottles of Injector cleaner...... No change.

Thought maybe Vacuum leak searched everywhere checked everything nothing to report. MAF sensor? ran the vehicle and unplugged it, engine fluttered for a millisecond and continued to run as normal. put plug back on with no difference. Thought O2 sensors. Unplugged both started car, no difference, by the way by removing these plugs i got no check engine warning lights or any other indicator something was unplugged. Removed O2 sensors to check for carbon build up or anything else, all seemed fine, I checked to continuation of current through O2 sensor plugs on car and the ones on the sensors and there is current, which still doesnt mean the sensors are working obviously but it doesnt explain why no warning light etc..

Could it be possible the errors were there before I purchased and had been cleared? therefore the ongoing problems dont appear to the ECU as new ones? It has been thirstier on the fuel consumption since the pinging started but i am at my wits end as to a solution.

Someone mentioned hot spots in cylinder could cause it? the compression test resulted in 150 - 160 in all cylinders.

Please i Need advice i have bought a 18.6ft caravan and this vehile is supposed to tow it, but with the pinging im worried im going to put a hole through a piston rendering it dead.

Thanks in advance.

 

Plug in a code scaner and check for "MIL LIGHT STATUS" which is "malfunction indicator light" - the check engine light, which with other lights should illuminate for a few seconds every startup as a bulb test. PO's (previous owner) have been known to cut wires, remove lamps, paint over lamps from the back side, and shove duct tape or cardboard between circuit boards to block lamps.

Then watch the status as vehicle warms up for open loop or closed loop fueling. If the system can't get correct signals from sensors, it can stay in "open loop" where it uses a lot more gas. Normally in closed loop most of the time when warmed up, except some short term conditions, like wide open throttle bursts, etc.

Of course you will likely find some codes. The ECU monitors the knock sensors and uses that and other info to adjust the spark timing for each cylinder individually all at the same time. So you can have 8 different advance values at the same time, in an attempt to control spark knock.

You can have a code scan for free at most parts stores, and some also rent/loan scanners. But that's here in the US. Down under, they are probably too busy watching the Aussie girls in skimpy spandex kicking butt in the Olympics.

You are wise to resolve this promptly. Were it mine, I would park it or only drive in a short emergency run with "bad" cylinder unplugged. I have had the pleasure of removing a spark plug and finding what looked like solder on the plug tip. It was as you say, the hole that was burned in the piston. Not in my Disco.

There is also a "tick" that comes from a slipping liner, but it usually happens once engine warms up, and disconnect of plug would not make it go away instantly.

 

I forgot to mention in first post that the MIL check engine light does illuminate when ignition in 11 setting with all other dash lights, and goes out when engine is started. one thing i have overlooked since making the 1st post and after reading through the RAVE manual, the IAC module i think its called which is apparently located on the side of the air box and i am yet to locate it to check it. would or could that also cause issues with the ECM if it is malfunctioning? the MAF sensor unplugged didnt seem to affect the engine as much as i thought it would as most other cars with MAF sensors if unplugged at idle would instantly stall engine. I did go to a garage today and the guy only had a scan tool that would work for LR3 and freelander and Range rover 2007 onwards. i'll try to track down someone in my area with a diagnostic tool suitable for the LR2 if i have no luck with the IAC sensor.

 

Put in the best petrol you can get.
Must be the best - high Octane.

Replace the fuel injector for that cylinder.
It is probably plugged and running lean.

I would also replace the O2 sensor for that side of the engine.

You should also only run NGK plugs. Or champions.
not some goofy gimmicky Bosch plat. tipped plugs or nonsense like that.

 

It is impossible for 1 cylinder to ping. Are you saying you have no fault code numbers?
If it were an injector, you would have codes or at least starting issues be it cold or hot.

 

It only pings in one cylinder. No fault mil light when I remove any sensors. I am yet to get a scan tool.

 

How much coolant are you using? If coolant is getting into one cylinder it will drown that spark and that cylinder will not produce the correct amount of power.
By removing the spark lead from #6 cylinder the coolant was able to just be pushed out the exhaust valve.
It may not be much coolant right now, but it will get worse.

 

Ok took D2 to a shop today, the guy had a snap-on diagnostic tool with a chip especially for LR2. it gave a heap of codes as I had been removing items and upsetting the ECU the day previous. Reset all codes and re started diagnostics, errors detected were both o2 sensors failed.

Live data analysis showed all other components working well, ie: Intake air temp sensor, MAF sensor TP sensor etc. all data showed good except the o2 sensor readings were 0.0 through rev range on both sensors. Im assuming this would cause the ECU to go into close loop mode ( or is it open loop??) either way he said get two new o2 sensors fit them and bring it back for a reset and further live data report.

Now in australia a single o2 sensor is approx $180.00AU although there is a universal item 4 wire o2 sensor which a supplier stated would be sufficient as long as the ohms is not more than 7 (btw this mean nothing to me) can someone advise if a universal o2 sensor would suffice? as they are approx 50% cheaper than the OEM product available here in backwards land australia.

 

Some people have had luck with the universal 02's , Most have not.
I would suggest going with the oem replacements

 

Sorry to say, but universals usually dont work.
I tried them on my wifes Volvo, threw O2 codes and ran rich.