High Performance Ignition Systems

PORSCHE 911 PRODUCTS BY PERMA-TUNE


WARNING: HIGH VOLTAGE! 

DISCONNECT 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 model:

o        Larger housing to accommodate more robust, reliable components.

o        Black anodized housing that resists corrosion and is paint able.

o        External fusible link to protect the vehicle and Perma-Tune from ground loop damage.

o        Flying lead connector for easy installation and maintenance.

 

Installation Instructions

 

1. Remove 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.

 

2. Perform 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 intercooler.

 

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.

 

4. Verify ignition timing according to the shop manual and engine bay placards for this car.

General Information

The 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. 

BENCH CHECK OF THE IGNITION BOX (Perma-Tune only)

The connector pin outs below are provided for your convenience. Note: No rewiring of the vehicle is required.

Pin 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 box.

Warning! To reduce risk of fire, replace the fusible link on the brown wire with a 20 gauge fusible link only.

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.

SERVICE NOTES

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 components.  Check 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.

TROUBLESHOOTING GUIDE

If 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.

If the engine does not start but kicks just as the ignition key is returned to the off position, perform a distributor signal test.

Hard 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.

The 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 components.

DIAGNOSTIC GUIDE

 Presented in approximate order of statistical occurrence.

IGNITION COIL

The 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 SC010 coil.

DISTRIBUTOR TRIGGER SIGNAL

The 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.

Full 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.

To 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.

SPEED RELAY

Turbo 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.

WARNING: 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

Turbo 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 relay.

WARNING: 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

High 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.

Cylinders 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 wear.

Cylinders 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 bearings.

GROUND CIRCUIT

Ground 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. 

There 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 0.5 Ohms.

WARNING:  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 CONNECTOR

The 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.  

 

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