My 87' 302 changes can manually be made to timing base by just unshunting PCM path, making the change & reshunting. How many other F-series engine share this ability? Did Ford eventually decide it wasn't "a better idea" after all, & remove that ability?
I believe all of the distributor type ignitions with fuel injected motors had this. It was their early (and primitive) way to control the ignition timing electronically depending on the sensor inputs to the computer. This is actually a good thing for modifications. If you adjust the "unshunted" base timing for elevation or octane, then the computer adjusts from that base set. They did away with this (obviously) when they moved to DIS (distributorless) ignition systems in 96-97. I think even the vans and cars had this setup before that.
Thanks for the info. I'm running 18 BTDC w/87 octane, but you have to adjust down the idle every 2 degrees starting w/12 or will start pinging as soon as they touch the gas pedal. Finewire rapidfires seem to do pretty well but I've heard Motorcraft copper are supposed to be the best but they wear fast.
That ping is bad news. I believe you are too far advanced. The stock base timing should be like 10 degrees btdc. If you are at 18, the timing is advanced 8 degrees too far for stock. you should only advance it that far if you are running higher octane or at elevations above 7000 ft.
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