Engine noises

[ChrisXJ]

Hi Guys,
Need some help with a problem with my XJ.
My XJ has the 4.0Ltr engine and while driving with the tacho at around 1300rpm and start to climb up a hill the engine has a ticking come rattle sound from it.This only happens when the revs remain the same but engine loads up
and has not kicked back a gear. I have spoken to some people who have all
said it sounds like engine ping. I normally run standard unleaded fuel in this car. I am in need of some expert help with this and wanting find if this is a common problem to have and is there a solution to this problem.

[Blujeep]

yes it sounds like ping or pre-ignition to me.
as for being a common problem, on 91 octane under load it sure is.
the easiest solution is better fuel, which will get better fuel economy as well.

Everyone has different experiences with PULP vs ULP but I gave it a try for around 3 months and documented the usage. The pinging going up hill definitely stopped completely for me so for some people here that's probably enough reason to use it. Fair enough I guess. I do use it if I'm towing the camper.
But in my experience the improvement in fuel economy was around 250ml per 100km. Whoahhhhh! That's less than 2%. (For my style of driving the XJ to and from work), the extra expense is nowhere near offset by the improved economy. Now I know some here feel pretty strongly about this and some also have very good records of their fuel usage. A lot of them will disagree with my experience.
Point is I think, the XJ fuel usage is pretty variable between not just vehicles but mainly drivers. Give it a go. But don't expect any dramatic improvement in economy. It does kill the pinging, but for me it just increases the fuel bill by 9.8 cents/l.

[turbomart]

If you can get the ethanol blend unleaded it has a higher octane rating than normal unleaded & is cheaper.
Alternatively you can mix premium & unleaded ,often 30% premium is enough to raise octane rating sufficiently.
Then there are lots of different octane boosters around, so just find what works for you.

[fisher]

Or just run LPG, it is over 100 octane (I think the worst you can get is still 102 octane)

As Turbomart said, it's probably cheaper just to buy some octane additive in bulk and give it a little bit in each tank as a booster.

[disco_nex]

PULP has hurt my fuel economy, but it runs smoother and no pinging. Try it, and see how it goes.

[tiiiiim]

In my Heep.
Normal Unleaded and the Ethanol blend fuels produce engine ping under load in my XJ.
I run Premium Unleaded and have no pinging engine noises.
95 or 98 octane.
I also travel further on a tank and better throttle response.
just by using a different nozzle at the bowser and forking out a couple of extra dollars

my 2 cents