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Old 10-08-2012, 12:36 PM
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Mister Sinister
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Default RE: Old new car question,please see what you think

For an engine to "ping", something has to ignite a pocket of air and fuel outside of the controlled burn in the cylinder. Detonation or knock is what occurs in relation to incorrect ignition timing on the combustion stroke. Pre-ignition is what occurs due to a physical issue inside the cylinder (hot spots), and occurs outside of the ignition process. Both are "pings", but for different reasons. Prolonged detonation can also lead to pre-ignition, by super-heating the cylinder. Since we don't know what exactly is happening with his engine (and since ignition timing is not adjustable on the Ford 4.6 engine), Ican only assume something outside of the combustion process is causing his ping (or pre-ignition to be more specific in this case). Carbon deposits, faulty EGRsystem, etc.

ORIGINAL: Anthoop

ORIGINAL: proanti
ORIGINAL: Anthoop
Higher octane fuel allows more advanced ignition timing...if you have a lower octane fuel than normal then you will need to retard the ign timing to prevent pinking.
It's purely about compression, not timing. The pinging is the fuel igniting under compression.
Cmon. If I have change to a lower octane fuel and the engine pinks then retarding the ignition will prevent pinking.

ORIGINAL: Mister Sinister

Pinging is the air/fuel mixture igniting OUTSIDEof the flame front, meaning not where/when optimum combustion happens in the cylinder. It's typically caused by a hot spot in the cylinder, which can often be caused by too much timing advance.
It sounds as though you are confusing pinking with pre-ignition?