Testing Ignition Advance In Warm-Up Phase (Only TSZ)

Testing ignition advance in warm-up phase (only TSZ)





- Connect tester.

- Warm up engine to approx. 80°C engine coolant temperature. Run at idle speed and take reading of ignition point.

- Detach vacuum line white/red at thermo valve (3). The ignition point must not alter.
If the ignition point alters, check whether vacuum lines are correctly laid and leaktight. Check thermo valve. The thermo valve should have clear passage above approx. 60°C.

- Detach vacuum line white/red at thermovalve (3) and plug the vacuum connection at thermovalve. The ignition point must be advanced approx. 8-12°.
If the ignition point is not advanced, check restrictor (1) for clear passage, check valve (2) and vacuum unit at distributor for leaktightness.


Function description




To improve the performance in the warm-up phase, the ignition point is advanced 8 - 12° CKA via the vacuum unit at the distributor up to a coolant temperature of approx. + 60 °C in addition to the centrifugal advance.

Below approx. 60 °C engine coolant temperature (thermo valve closed) the vacuum passes from the intake manifold via the restrictor (1) and check valve (2) to the vacuum unit at the distributor when the engine starts.

The check valve (2) ensures that the maximum vacuum is retained at the distributor (also when accelerating) which results in the additional ignition advance via the vacuum unit.

Above approx. 60 °C the thermovalve (3) opens, and the vacuum is reduced at idle speed to the throttle valve assembly.

A restrictor (1) is installed to ensure that the vacuum for the other connected components cannot escape through the connection at the intake manifold at idle speed.