A recent febi Technical Blog describes some problems that can occur with hard cranking, rattling on cranking or a non-start on some Volkswagen, Audi, Seat and Skoda models.

Problem
Extended engine-cranking time before starting, or a rattling noise from the engine area. Engine management fault lamp illuminated, or engine not starting.

Possible fault codes stored:

• P0016 Camshaft timing advance (Bank 1) target value not attained
• P0328 Knock sensor 1 single too high

Cause
Timing chain elongation. Failure of the oil non-return valve for the camshaft timing control.

Solution
When diagnosing the symptoms listed above, there maybe more than one cause.

If the engine is not running smoothly, with one or more fault codes present, monitor the timing data from the ECU. This should not exceed +/- 5 degrees.

If the data is reading over 5 degrees at idle, or during a snap wide open throttle test, then the screen for the oil non return valve, located in the camshaft adjuster bracket, has come apart and lodged itself within the camshaft adjuster spool valve and the intake camshaft adjuster.

If the engine does not run, start by checking the mechanical timing. If the mechanical timing is found to be incorrect, determine the cause of the incorrect timing. e.g., timing chain has jumped position. Inspect for a missing oil screen in the camshaft adjuster bracket. If there has been piston to valve contact, the complete timing chain kit will need to be replaced, along with the cylinder head assembly and any other damaged parts.

If the oil screen is present and the mechanical timing is correct, inspect the intake camshaft spool valve, for damage, or if the end of the valve has come apart, resulting in a portion of the spool valve being left in the adjuster bore.

Replace the timing chain kit, camshaft adjuster bracket, intake camshaft and the spool valve adjuster.

Follow the vehicle manufacturer’s procedures during the inspection and replacement. It is recommended to replace the engine oil and filter as part of the repair.