Poor Start Or Non Start Related To Ignition Module Failure (86/08/94/US)

POOR START OR NON START RELATED TO IGNITION MODULE FAILURE

TECHNICAL SERVICE BULLETIN

DETAIL

Some instances of poor start/non start have been reported on vehicles in the VIN range shown above. When this symptom occurs it can be as a result of failure by the module to control the coil primary current accurately. This leads to dwell angles in excess of 40 degrees at idle. In certain conditions the high current causes the coil to overheat and the insulating compound may leak from the unit, resulting in eventual failure to start. On Range Rover and Discovery models from the latter VIN's shown above, a remote mounted module has been introduced into production to reduce the likelihood of failure. Mounting the module remote away from the distributor reduces temperature, electrical interference and vibration , thus minimizing the likelihood of failure.

ACTION REQUIRED

For instances of excessive dwell angle at idle or ignition module/coil failure, fit the Service kit identified below and where coil leakage is experienced fit a new coil.

PARTS INFORMATION

STC 1856 Service Kit.

PRC 6574 Coil

WARRANTY

Normal warranty policy and procedures apply.

SRO	Description	Comp. Code	Time
86.35.89/26	Ignition module	7B8U	00.50 hour
---	Ignition coil	7A8Z	---

PROCEDURE

1. Remove the distributor assembly from the front cover assembly.
2. Remove the failed module from the side of the distributor.
3. Fit the dummy module (red in color) which is supplied in the kit onto the side of the distributor ensuring that the blue connector terminals are a tight fit and using the original screws tighten to 1.2 Nm.

   Care must be taken not to over torque the screws.

4. Refit the distributor to the front cover.

   Ensure the engine is set to T.D.C and that the oil pump drive and rotor arm are in the correct orientation.

5. With the distributor correctly fitted, place the heatsink bracket assembly on the wing near the ignition coil. Connect the Econoseal connector of the service pick-up lead to the Econoseal connector attached to the heatsink bracket. (See Fig 2 )
6. Feed the 3-pin mini timer connector end of the lead under the front of the air cleaner housing and connect to the dummy module on the distributor. (See Fig 2 )
   Fig 2: Connecting Service Pick-up Lead to Heatsink Bracket & Dummy Module

   
7. Cable-clip/tie wrap original engine harness connector back onto the harness. (See Fig 3 )
   Fig 3: Securing Engine Harness Connector to Harness

   
8. Disconnect the connections to the coil as follows: Range Rover Prior VIN LH 624781 Disconnect the white/black wire from the coil negative terminal, leaving the black PVC sleeved white/black wire attached to the coil, tie-wrap the disconnected wire out of the way as it is now redundant.

   On vehicles post the above VIN numbers. Disconnect the red and blue wires from the coil terminals and tie-wrap out of the way as these leads are no longer used.

9. Remove the ignition coil. Ensure mounting nuts are kept safe for use later.
10. Only applicable to Range Rover prior to LH 647645. Disconnect the suppression capacitor lead and the positive feed wire from the twin blade lucar connector on the coil positive terminal. Remove the twin blade connector from the coil. Take the triple blade lucar connector provided in the kit and fit to the coil positive terminal (tighten terminal to 3 Nm). Reconnect the positive feed wire and the suppression capacitor feed wire to the new connector.
11. Fit the heatsink bracket beneath the coil. Remount the coil and heatsink bracket to the inner wing. Connect the two connectors of the fly lead to the ignition coil. (See Fig 4 for installed position).
    Fig 4: Proper Installation of Heatsink Bracket

    
12. Cable tie the service pick-up lead to the engine harness. (See Fig 3 ).
13. Check all wiring installation for security and clearance from moving parts.
14. Start the engine and re-set ignition timing as detailed in the workshop manual.