Peugeot 405 Manual

Ignition timing - checking and adjustment
Ignition system / Ignition timing - checking and adjustment

Electronic ignition system 1 To check the ignition timing, a stroboscopic timing light will be required. It is also recommended that the flywheel timing mark is highlighted as follows.

2 Remove the plastic cover from the aperture on the front of the transmission clutch housing. Using a socket and suitable extension bar on the crankshaft pulley bolt, slowly turn the engine over until the timing mark (a straight line) scribed on the edge of the flywheel appears in the aperture. Highlight the line with quick-drying white paint - typistТs correction fluid is ideal (see illustrations).

6.2a Removing the plastic cover from the timing aperture
6.2a Removing the plastic cover from the timing aperture

6.2b Timing marks on the flywheel and timing plate
6.2b Timing marks on the flywheel and timing plate

3 Start the engine, allow it to warm up to operating temperature, and then stop it.

4 Disconnect the vacuum hose from the distributor diaphragm, and plug the hose end.

5 Connect the timing light to No 1 cylinder spark plug lead (No 1 cylinder is at the transmission end of the engine) as described in the timing light manufacturerТs instructions.

6 Start the engine, allowing it to idle at the specified speed, and point the timing light at the transmission housing aperture. The flywheel timing mark should be aligned with the appropriate notch on the timing plate (refer to the Specifications for the correct setting). The numbers on the plate indicate degrees Before Top Dead Centre (BTDC).

7 If adjustment is necessary, slacken the two distributor mounting nuts, then slowly rotate the distributor body as required until the flywheel mark and the timing plate notch are brought into alignment. Once the marks are correctly aligned, hold the distributor stationary and tighten its mounting nuts.

Recheck that the timing marks are still correctly aligned and, if necessary, repeat the adjustment procedure.

8 When the timing is correctly set, increase the engine speed, and check that the pulley mark advances to beyond the beginning of the timing plate reference marks, returning to the specified mark when the engine is allowed to idle. This shows that the centrifugal advance mechanism is functioning; if a detailed check is thought necessary, this must be left to a Peugeot dealer having the necessary equipment. Reconnect the vacuum hose to the distributor, and repeat the check.

The rate of advance should significantly increase if the vacuum diaphragm is functioning correctly, but again a detailed check must be left to a Peugeot dealer.

9 When the ignition timing is correct, stop the engine and disconnect the timing light.

Integral and
Direct ignition systems
10 On these systems, there are no timing marks on the flywheel or crankshaft pulley.

The timing is constantly being monitored and adjusted by the engine management ECU, and nominal values cannot be given.

Therefore, it is not possible for the home mechanic to check the ignition timing.

11 The only way in which the ignition timing can be checked is using special electronic test equipment, connected to the engine management system diagnostic connector (refer to the relevant Part of Chapter 4 for further information).

12 On models with Magneti Marelli engine management systems, adjustment of the ignition timing is possible. However, adjustments can be made only by reprogramming the ECU using the special test equipment (see relevant Part of Chapter 4).

13 On all other models, with Bosch engine management systems, no adjustment of the ignition timing is possible. Should the ignition timing be incorrect, then a fault must be present in the engine management system.

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