Octane

[stuwa]

I had a great holiday in Shark Bay last week fishing, exploring etc, it was great to use the PXJ'00 for what it was designed for. My mate with a Toyota SukLux was well impressed by its performance offroad, its all stock apart from an air compressor. It took just over nine hours driving to get there from Perth, about eleven hours in total and the fuel economy was pretty awesome I think - 11.5 litres per 100km and thats average for the whole trip.
Anyway, that brings me to a point of interest. We decided one day to take a trip out to the Useless Loop/Steep point area from Denham, its about a two to three hour drive out to some very remote but beautiful country (make sure you slowly squeeze 90 litres into your stock tank before you set off!) and after about three hours of wheelin' on very slow tracks we emerged onto a beach with extremly soft sand. Now the engine was very hot by this stage but nothing abnormal about that apart from the 'pinging' noise, pre detination or whatever, now coming from the engine! Anyway to cut a long one, I let the engine cool and we made our slow way back to Denham (and Perth a few days later).
Question: Why the pinging? Is 11.5 litres per 100km too lean? Did I overwork the engine? Does the timing need adjusting? or is it just that the fuel in Shark Bay is shithouse? My revhead mate who is into all things performance suggests that next time I go wheelin' I put premium in the tank - higher octane, higher flash point but surely that shouldn't be necessary.
I'm not to concerned right now as its due for a service this week but any comments/suggestions would be good...

[wrench]

Premium is definately worth a try. I have several customers & myself who feel they get better performance & economy on PULP. Its a better blend than the usual ULP crap which varies dramatically. As my XJ used to ping slightly under severe load I always tried to run PULP on trips & still do in my WJ.
Better not bitch about your economy tho I might suggest an injector service.
HTH
David

[Grant]

I have never had any pinging from my Xj and drive it underall conditions and weather types.
Sounds mor elike you got a good mix of ULP and ethanol and a lot more than the max allowable amount of 10% sounds more like about 20-25% ethanol

[Just Jeepin]

Premium all the way Stuwa,

I have said it before and I will say it again...

My XJ has been on PULP since I got her and what I found is that the mileage increase and the smoother running has made paying the extra cents a litre worth it...

Also I usually stick to two brands Mobil 8000 and Shell Optimax...

Recently, I had put normal unleaded to give it a go and the mileage I got out of it is crap.

So PULP is the go...

[stuwa]

Cheers , I'll give it a go on next tank fill and take it down on the beach, Ill let you know how it goes.

[narly]

Allway's been gunna try PULP myself. Used to run the Suby on it now and again and it certainly made a difference to that .

[Gojeep]

I have found that my customers with the later XJ's have more problems with pinging after Jeep closed the panel off in front of the airbox intake. I recommend PULP as well and is also what Jeep told them to do. With one he was doing a large Outback trip where PULP is un-available and fitting a snorkel ( Airflow ) solved the problem just as well due to the cooler air.
I dont have pinging problems having not the panel blocked off but still run on PULP as is better for the injectors and I always get at least 1l/100 kms better which pays for the price difference and any more than that ( often get 2l/100kms better ) actually saves me money!