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1984 Mer cury Marquis Starting Problem

This car has the 5.0 Liter V8 CFM with Duraspark ignition and has 89 Kmiles on it. Car suddenly would not start after running perfectly the day before. It?s getting fuel and spark looks OK. With the rotor aligned with plug/cylinder #1, the timing is in excess of 30 Deg BTDC. When cranked with a timing light referenced to Cyl #1, no timing marks are observable.

The engine may have a jumped timing chain.

The 5.0 liter engine in your vintage of Ford has a camshaft gear with teeth made of plastic. These plastic teeth can break off the hub of the camshaft sprocket causing the timing chain to jump time.

A quick way to determine if this has happened is to drain the oil, and inspect the drained oil for bits of plastic.