'97 XJ with pinging noise

Sounds like spark knock. You say it happens with all kinds of gas, do you mean brands or grades? If you have tried different grades does it do it less with better (higher octane) gas? My Cherokee with the 6 spark knocks pretty badly with regular but with midrange hardly does it at all. I also noticed that after changing to platinum plugs the pinging went down.

Jeff DeWitt

Deparko wrote:

Some things you can do:

1. I just heard of a product called BK-44.
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   I heard this is very good stuff.2. Raise octane level.3. Run cooler plugs.

Here's another:

everything i've ever heard about gas is that it is pretty much all the same... same source, same trucks, etc.

aren't the additives more of a marketing ploy?

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.