WARNING: HIGH VOLTAGE!
THE BATTERY BEFORE INSTALLING
OR SERVICING ANY IGNITION SYSTEMS COMPONENTS.
Failure to follow these
instructions and the vehicle owners handbook and shop
manual could result in serious personal injury, death
and or damage to property. This part is designed to be
installed by a mechanic that is familiar with European
automobiles and safety standards.
New features of the
Model 930902 Perma-Tune
The Model 930902 supersedes the Model 930
Perma-Tune and has many improvements over the older
Larger housing to accommodate more robust, reliable components.
Black anodized housing that resists corrosion and is paint able.
External fusible link to protect the vehicle and Perma-Tune from ground
Flying lead connector for easy installation and maintenance.
the old ignition module from the car according to the
shop manual for this car. Perform a bench check of the
module according to the manufacturers specifications.
Perform any maintenance procedure needed, if the bench
check procedure indicates so, to prevent damaging the
new ignition module upon its installation. NOTE:
On some cars, the relay panel where the ignition box is
located must be unbolted from the car so that the nuts
can be held while the bolts for the ignition box are unscrewed.
One of the screws for the relay panel mounting also holds
the braided ground strap that provides the ground for
the relay panel. This ground strap can be easy to forget
to hook back up because when it is removed from the relay
panel it will fall forward between the fuel filter and
fuel accumulator where it cannot be seen. It is extremely
important that this ground strap be reconnected when the
relay panel is bolted back to the car. Failure to reconnect
this ground strap may result in damage to the car or your
new ignition box.
an ignition coil resistance test. Replace the coil if
the coil does not test to specifications or if there is
evidence of oil or tar leaking from the coil. Note:
To avoid potential damage to your new ignition box, we recommend that you replace the ignition
coil when the ignition box is replaced. On intercooler
equipped cars, use the stock ignition replacement coil
ONLY. The SC010 Perma-Tune coil will not fit under the
3. Bolt the
ignition box to the relay panel. Before plugging in the
connector, perform the distributor signal test and the
ignition module ground test. If the tests indicate a fault
exists, repair any fault that may exist in the vehicle,
and then plug in the module. Note: To avoid potential damage to your new ignition
box, we recommend that you perform the ground loop test
described on our web site technical support page before
plugging in a new ignition box.
ignition timing according to the shop manual and engine
bay placards for this car.
Model 930902 Perma-Tune is designed to replace the stock
ignition box on all Porsche Turbo cars between1976 and
1977 and will bolt up and plug in to the same location
as the stock system. The Model 930902 not only replaces
the stock system, it is a performance upgrade boosting
the spark energy by a factor of three. This increase in
spark energy allows your engine to make more power with
the same amount of fuel. Spark plug gaps can be increased
(spark plug gaps over .060" are not recommended but
are possible, some turbo engines use spark plugs that
cannot be regapped), solid core copper spark plug wire
can be used and fuel mixture can be adjusted to increase
performance. The Model RV020 Rev Limiter and the Model
PR020 Pre Amp and aftermarket tachometers can be used
with the Model 930902 Ignition Module. Use pin 5 for the
rev limiter trigger connection and aftermarket tachometers.
The Porsche Turbo cars of the mid seventies could have
either the eight pin or the six pin ignition module. Most
of the time the eight pin modules were on the European
version turbo but there have been exceptions to the rule
both ways so we have included the information for both
types. Aside from the connector configuration, the
difference between the two modules is that they have different
tachometer signals to accommodate different speed relays,
run on relays and tachometers. We call the 8 pin
module the Model 930902 and the six pin module the Model
911SC902. The 911SC902 modules are also used on the 3.0
Liter Porsche engine.
By design, Perma-Tune ignitions make very little heat
of their own. Wiring
problems external of the unit will cause your Perma-Tune
to get hotter to the touch than the other components under
the hood. If this is the case we recommend you refer to
the diagnostics section at the Perma-Tune technical web
site. The Model 930902 Perma-Tune is designed to replace
the stock ignition box and will bolt up and plug in to
the same location as the stock system. If you need a harness
to install this ignition system, exchange it for a Model
MP Perma-Tune. If you are installing a 930902 engine in
a 911 body, use the model 911EX902 Engine Exchange
kit. If the connector does not match that of the car,
you have the wrong unit for that car. In either case contact
Perma-Tune for assistance with exchanges. The dealer you
purchased your Perma-Tune from is not authorized to issue
warranty replacement or exchange units. Please contact
the factory for technical and warranty assistance. If
you have a turbo car, make certain that the speed relay
did not cause the failure of the original ignition box
before you install the new box.
CHECK OF THE IGNITION BOX (Perma-Tune only)
The connector pin outs below are provided
for your convenience. Note: No rewiring of the vehicle
1 to 3 = 3.300 Ohms + - 100 Ohms is normal. Zero
Ohms or lower than normal resistance indicates defective
ignition coil damage to the box.
Pin 2, 3 and 6 = Zero Ohms is normal. Greater than 0.2 Ohms indicates battery terminal reversal
damage to the box.
Pin 3 to mounting hole flange = Zero Ohms is normal. Greater than
0.2 Ohms between pin 3 and the mounting hole flange indicates
ground loop or battery terminal reversal damage to the
Warning! To reduce risk of fire, replace
the fusible link on the brown wire with a 20 gauge fusible
Pin 6 to 8 = 200uF to 280uF is normal. This reading requires the use of a meter capable of reading
capacitance. This reading
is polarity sensitive with Pin
8 being positive and pin 8 negative. Readings
greater than or less than this specification indicates
ground loop or alternator damage to the box.
Pin 3 to Pin 5 Zero Ohms
is normal. More than 1-Ohm resistance indicates damage
to the fusible link inside the box.
To avoid damage to your Perma-Tune and voiding your warranty: Do not attach
a dwell meter to the coil. Do not connect 12 volts to
the coil. Do not use a test light or jumper wire on the
ignition box, tachometer or ignition coil. Make sure the
relay panel ground cable, engine ground cable and battery
negative cable connections are not defective. Remove any
radio noise suppressers or condensers that may be attached
to the ignition system, they are not needed and may cause
intermittent ignition problems. Check spark plug wires,
spark plug connectors (resistor type), and distributor
cap for corrosion and carbon tracking. Check the rotor
for shorts, defective resistor and/or defective rev limiter
fuel for water contamination; check fuel pump pressure
and fuel injection settings.
Unlike the stock ignition systems, Perma-Tune ignitions
make no audible sounds when the ignition switch is on
and make very little heat of their own under normal operating
conditions. To avoid potential damage to your
new ignition box, we recommend that you perform the ground
loop test described on our web site technical support
page before plugging in a new ignition box.
the engine does not start but kicks just as the ignition
key is released from the start position, check the ignition
switch start circuit. To check this circuit, place a Voltmeter
on the power wire of the Perma-Tune and observe the meter
while cranking the engine.
the engine does not start but kicks just as the ignition
key is returned to the off position, perform a distributor
start problems can be mechanical or electrical in nature.
Defective starter components can cause excessive drain
on the battery leaving insufficient residual energy to
allow the Perma-Tune to function. As a general rule, if
there are 5 Volts available to the Perma-Tune during cranking
of the engine, it will produce a spark, no matter how
slow the engine is being cranked.
source of most intermittent problems are addressed in
the diagnostic guide. Intermittent no start conditions
may also be caused by a faulty electronic tachometer.
Disconnect the tachometer from the ignition system if
so equipped, if the problem goes away, replace the tachometer.
Also disconnect any noise suppressors, condensers or load
resistors. If the Perma-Tune unit gets any hotter than
the rest of the components in the engine compartment,
there are problems in the wiring of the car or faulty
connections between the Perma-Tune and the car. Refer
to your shop manual and the diagnostic guide to find and
repair the problem to avoid damaging your electrical system
in approximate order of statistical occurrence.
most common cause of engine ignition failure is the ignition
coil. When an ignition coil shorts between the primary
and secondary windings, the stock ignition box will be
destroyed by the high voltage feedback from the defective
coil. If the defective box is replaced without replacing
the coil, the new box will also be destroyed in a short
time. If the stock box is replaced with a Perma-Tune box,
the car may still run but run poorly or develop intermittent
problems a short time after installation. The Perma-Tune
replacement box can usually withstand feedback from a
defective coil until the coil shorts completely and the
car stops running at all. In most cases the coil can be
replaced and all is well, however, in some cases the box
can be damaged. Refer to the Model 930902 installation
guide for more information on the coil. Refer to BENCH
TEST for the coil damage diagnostic procedure on the ignition box. You can use Perma-Tunes new
DISTRIBUTOR TRIGGER SIGNAL
second most common cause of engine ignition failure is
the ignition trigger circuit. Since the ignition box is
controlled by the magnetic pulse generator located inside
the distributor, any disruption in the triggering signal
will cause the ignition box to malfunction. Be aware that
the connectors that carry the signal to the box can push
back in the housing. Pull the rubber boot back to
inspect the connection between the box and harness.
disassembly and inspection of the distributor is highly
recommended due to the intermittent nature of triggering
problems. Pay special attention to the distributor trigger
shielded cable ( green wire ), magnetic pulse generator
magnet and magnetic pulse generator winding connection
as these parts are known to fail in combination. Evidence
of arching between the magnetic pulse generator magnet
points indicates a defective rotor. In this case replace
the rotor, magnetic pulse winding, green wire and ignition
box. The Perma-Tune high performance triggering
is so accurate that worn out distributor shaft bearings
can be detected by the tachometer. This is indicated by
the tachometer needle slightly bouncing at idle. Trigger
signal problems can cause double triggering which results
in a weak ignition spark. Due to the lower triggering
resolution of the stock ignition box, some symptoms of
trigger signal problems can be more evident after the
Perma-Tune is installed. Refer to the vehicle maintenance
manual for triggering signal waveform specifications and
distributor repair instructions.
quickly test the triggering circuit without the use of
an oscilloscope: Unplug the harness connector from the
ignition box. Refer to the 930902 Installation Instructions
Bench Check diagram; connect an Ohmmeter between pins
6 or pin 3 and pin 7 of the harness connector. To prevent
the possibility of misdiagnosis, tug on the green triggering
signal wire located at the base of the distributor while
viewing the meter. The published specification for the
magnetic pulse generator is 600 Ohms +- 100. Our experience
has shown that a variation of +- 25 Ohm indicates a need
to repair defective connections or to replace the magnetic
pulse generator windings.
cars are equipped with a speed relay that the non turbo
cars do not have. This relay serves a safety function
that shuts down the fuel pumps in the event of an engine
over rev event. Turbo charged engines can sometimes over
boost and run away causing an uncontrolled over rev of
the engine. The speed relay can sense engine RPM and shut
down the fuel pumps to control the engine. The speed relay
can malfunction and in turn cause the ignition module
and or fuel pumps to malfunction. This relay is very sophisticated
piece of electronics that is usually mounted under the
driver seat. Refer to the shop manual for this vehicle
for troubleshooting the speed relay and tachometer. The
shop manual will describe how to jumper out the speed
relay, if the problem goes away when the relay is jumped,
replace the speed relay. If the problem does not go away,
plug the speed relay back in and unplug the tachometer,
if the problem goes away, replace the tachometer.
Do not leave
the relay jumped. Disconnect the jumper when the test
is done to avoid the possibility of fire and or over rev
damage to the engine.
RUN ON RELAY
cars are equipped with a run on relay that the non turbo
cars do not have. This relay serves a safety function
and prevents turbo backfire when the engine is shut down.
This relay is a special timer relay that is usually mounted
on the relay panel where the ignition module is located.
It works by keeping the engine ignition system operational
for several seconds after the ignition key is turned off.
This allows fuel to be burned off as the engine shuts
down rather than accumulating in the hot turbo section
causing a backfire. This relay can malfunction and in
turn cause the ignition module to malfunction. Refer to
the shop manual on how to jumper out this relay. If the
problem goes away when the relay is jumped, replace the
Do not leave the relay jumped. Disconnect the jumper
when the test is done to avoid the possibility of fire
and or damage to the turbo and waste gate.
SPARK PLUG CIRCUIT
Voltage circuit problems can become more evident after
a Perma-Tune is installed. Rough idle or a miss in the
mid RPM range can mean there is a defective coil, cap,
rotor, spark plug wire, or spark plug wire connector.
Since the Perma-Tune is a high performance ignition, these
problems can be masked by installing a comparatively low
power stock ignition box in the car. When examining the
spark plug voltage with an oscilloscope, all six cylinders
must read the same. The use of dielectric grease on all
electrical connections is highly recommended, especially
on spark plug boots.
that read lower than the others may indicate: Shorted or fouled spark plug. Narrow
spark plug gap. Shorted spark plug cable. Excessively
rich mixture due to leaking injector or carburetor. Low
compression due to bad valves, rings or other mechanical
that read higher than the others may indicate: Open plug cable. Excessively wide spark
gap. Worn spark plug. Lean misfire due to an induction
leak, carburetor problems or restricted fuel injector.
Overly advanced ignition timing. Worn distributor shaft
loop problems are very common on Porsche cars, especially
on cars that do not get driven much. Symptoms of a ground
loop problem are many, can effect the entire electrical
system and are often intermittent in nature. Some indications
of ground loop problems are: hard starts, poor engine
performance, radio reception interference, weak engine
ignition spark, false alternator failure light, repeated
ignition box failures, repeated alternator failures, repeated
tachometer failures, repeated relay failures, dim interior
lights. Especially common on the 930 are defective ground
connections between the engine and chassis of the car.
The defective ground connection diverts current from the
starter though the ignition system. The higher the ground
connection resistance, the more current will flow through
the ignition system during cranking and the faster the
ignition will be damaged.
are many ways to troubleshoot ground connections; here
is a fast way to do it on a 930. Use a digital Ohmmeter
set to its most sensitive setting, an analogue meter is
not sensitive enough to use this technique. To reduce
the chance of misdiagnosis, tug on the wire being tested
while watching the meter and perform the test in the order
as follows: Stab the black lead of the meter directly
into the lead of the battery minus terminal and connect
the red lead to the chassis of the car, do not connect
the red lead to the battery ground connection. The resistance
should read less than 0.5 Ohms, any more than that indicates
a bad connection. Move to the back of the car and connect
the black lead of the meter to the chassis of the car
and the red lead to the engine case, again the meter should
read less than 0.5 Ohms. Disconnect the harness connector
from the ignition box. Connect the black lead of the meter
to the engine case and the red lead to the ignition box
ground wire, pin 3, of the harness connector. Refer to
the Model 930 Installation Instructions diagram for pin
1 location. Again the meter should read less than
To avoid the possibility
of fire, do not install additional ground wires on the
vehicle and replace defective ground wires using only
wires of the same gauge.
rectangular 14-pin engine harness connector causes many
problems that are misdiagnosed as ignition box problems.
This connector is located on the aft end of the relay
box which is located aft of the ignition box. Corrosion
attacks the connector at the pin and socket mating points
and inside each half of the connector at the wire to connector
crimp connection. Corrosion at this connector is almost
certain to occur if the protective relay box cover is
missing or if the engine compartment was cleaned with
a high-pressure water hose.