Porsche 996 TT, Repair Manual

Page: 1789 / 2099

Interference noises due to alternator
Work instruction Yes No
1
Connect a plug connection
to the alternator.
Start
engine.
Minimise the volume at the
radio.
Switch on high loads and
change the engine speed
with brief accelerations.
Are the interference noises still
present?
1. Check the connections of the battery. Make sure that
all connections are seated properly, are tightened and
are not corroded.
2. Check the ground connection of the engine, the alternator
and the battery's negative terminal and measure with a
multimeter at the negative terminal of the battery and the
respective ground point (potential difference).
3. Make sure that all ground connections are fully tightened
and clean.
4. Check the connections of the alternator.
If necessary: clean and repair the connections and, if necessary,
install a condenser ’ End
’
End
Interference noises due to engine
The following points should be checked first:
Note
Make sure that the battery connections are seated properly and that the ground connection is
guaranteed. •
Check whether the ignition coils are loose or defective. •
Check the plug connections and supply lines for the ignition coils for damage. •
Check the ground connections on the engine.
•
Check whether the correct spark plugs have been installed and that the electrode gap is OK. •
Work instruction Yes No
1 Does the interference noise change
with the engine speed?
This work instruction must not be
carried out on public roads. Drive the vehicle in 1st or 2nd gear at a
speed of 3,000 rpm (with audible noise),
then suddenly remove the pressure from the
accelerator.
Noise present: ’
1.
Does the
interference
noise only
occur when the
car is driving?
’ Step 2
einordnung
Interference noises due to alternator 1726