I test-drove a 1994 Honda Accord with 140K today. Looking for reliable car for relative, and this was one of the better options, on paper at least, in the price range.
It drove like a used car, but I was concerned about one thing: A ping when accelerating from low speed. It didn’t do it constantly, but only when going from a standstill or slowdown back up to speed. The seller said he’d been told it was an issue with the catalytic converter. I’ve been told that a higher octane fuel will sometimes quell a ping in an engine with no knock sensor.
Is this something I should be worried about? Is the high-octane rumor true? The car was otherwise very nicely maintained.
In most cases, a pre-ignition rattle or ping is caused by a problem in the EGR circuit. This would require a more detailed diagnosis to determine exactly where in the EGR system the problem lies.
This should be an ignition distributor equipped model and a ping can also be caused by excessive timing advance.
Either of the above can be damaging to an engine.
High octane may settle the ping down but that’s not really a cure for the problem.
If it’s in the EGR system, many times this is due to port clogging which must be cleaned out, etc.
I would take both the catalytic converter and high octane comments with grains of salt. Hope that helps.