1988 CITROEN CX Service Manual

CHECKING THE IGNlTlON ADVANCE
of the I.E.I. system
On CX vehicles fitted with I.E.I.
These vehicles having fixed sensors, are not equipped with TDC sensors
I) Marking the TDC:
Draw a mark on the crankcase, in the opening located next to the flywheel pick up sensor
- Remove the 1st or 4th cylinder sparking plug
- Finding the T.D.C. with a locating peg: jack up the vehicle on one side and engage a gear.
Rotate the road wheel in one direction.
Mark down the place where locating pin will enter the flywheel.
Draw a temporary line on the flywheel ring. Rotate the lifted road wheel in the opposite direction, with
the pin still engaged. Mark the position of the pin in the flywheel ring. Take an average of these two marks-
which corresponds to the TDC. Draw a white paint mark on the flywheel ring, opposite the one on the
crankcase.
- Refit the sparking plug.
2) Testing the development of the speedometer advance curve:
- Connect a phase shifting strobe lamp
- Set the strobe lamp to the 2 cyl. u stroke or 1 cyl. 2 stroke position.
- Disconnect the pipe of the load correction depression operated capsule from the inlet manifold. Blank
off the orifice.
- Run the engine and check the advance curve development.
3) Testing the operation of the air-operated capsule on normally aspirated engines:
- Blank off the vacuum capsule venting orifice.
- Connect a vacuum pump to the capsule pipe.
- Run the engine to 2.000 rpm; record the advance reading.
- Create a 400 mbar depression in the vacuum capsule.
The ignition advance increases by about 15’ and the engine accelerates to 200 rpm approx.
On turbocharged engines:
- Connect a vacuum-pressure pump to the capsule pipe.
- Rotate the engine to 200 rpm. Read the advance.
- Build up a 500 mbar depression in the capsule:
- There will be a 22” increase of the ignition advance, approx. and about a 500 rpm engine acceleration.
- Build up a 500 mbar pressure in the capsule:
- There will be a -1 1 o decrease of the ignition advance, approx. and about a 500 rpm engine slowing down
- Pinking: occurs when the engine speed exceeds 1.000 rpm. The warning lamp should light up in the
following cases:
- anti-knock sensor system broken or short-circuited,
- knock sensor broken or short circuited,
- improper earthing provided by the knock sensor.
- Check the operation with the strobe lamp, and a 2.000 rpm engine speed Record the ignition timing.
- Disconnect the knock sensor:
The ignition advance decreases by IO’ approx.

t i i i W
I I
I I
I I
8531