Deparko wrote:
> Howdy,
> I have a '97 XJ with about 87k on it. Ever since I bought it (new) it starts
> a tinty pinging sound when under stress , going up hill or pushing it. I've
> asked the dealer and the people who work on it several times throughout the
> years about it. They basically said its bad gas but I don't believe them..it
> happens with all types of gas...sometimes (rarely) it does not happen but
> most of the time it does..others have told me my plugs are fouling..use the
> stock ones..etc. Bottom line: problem is still not solved..when going up
> hill or trying to pass I get a pinging sound..if anyone can give me guidance
> ..it would be greatly appreciated.

The key is you say it's been pinging since it was brand new. Unless the
XJ is rated at a higher octane gas (owners manual will tell you and
others here will know) and you've been only feeding it 87 octane. Then
you had a lemon from the git go.

I'd guess it came off the line with an ignition system defect or
something wrong with the timing advance that causes it to not adjust
correctly when your computer gets feedback from the sensors. Perhaps
even a failed or faulty sensor.

If it had a slight ping new, then you can rule out almost all the normal
easy wear and age related causes of ping. It's not a clogged air
filter/intake/gumed up air sensor. It's not dirty plugs unless your
engine is seriously screwed up and is fouling the plugs instantly from
bad ignition or timing (But then I wouldn't put this past any Jeep
product, there's a good reason that Jeep is the only major brand anymore
that has 1980's 36,000 mile warrantees).

I hate to say "you should have" but 5 or 6 years ago would have been the
time to insist on getting the ping fixed under warrantee... if it's been
pinging along for 6 years chances are you've got some pretty f'd up
valves, cylinder heads and piston rings. Ping (even slight ping) over
that long a span is like taking a ball peen hammer to everything in the
combustion chamber.

Your best revenge at this point might be taking it to that Jeep dealer
and haggling down a left over 03 model, and then _after_ you get your
price and a loan from a real bank at 6 or 7% insist on full trade in
value for it. They'll lose money on the 03 and your trade in.