Originally Posted by
YNOT
1a (short answer), Pinging is the sound the engine makes when the timing is over advanced.
1b (long answer), Normally in a 4 stroke petrol engine you set the ignition so the spark occurs a couple of degrees before top dead centre (BTDC) on the compression stroke, which means that the flame front in the combustion chamber is propagating as the piston finishes rising in the cylinder. Setting it this way ensures that maximum combustion pressure is achieved at TDC for best power. If the timing is over advanced maximum combustion pressure will occur as the piston is still rising on the compression stroke which causes a knocking or pinging sound as it tries to push the piston back down the compression stroke rather than down on the power stroke.
2, High octane fuels like LPG can handle a bit more advance, the downside being for dual fuel cars like yours that you have to comprimise the timing for both fuels. With the ECUtalk you will have the abillity leave the distributor timing advanced for LPG but retard the timing back to normal through the ECUtalk when you run on petrol so you don't have to comprimise for either fuel.
Tony
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