Note. You will need the following special tools to perform the procedures below:
- - Tachometer and stroboscope;
- - Duration meter (by angle) closed state of the distributor breaker contacts (for models 4.2 l).
Patrol/Maverick vehicles covered in this manual are fitted with one of two types of distributors. The 3.0L models use an electronic ignition distributor, the 4.2L model uses a distributor with a contact breaker.
The distributors are equipped with a special block that limits the maximum speed to 5000 ÷ 5400 per minute and is accordingly called the speed limiter. The block consists of a spring-loaded rotary button and a special cover, which, when the engine speed reaches a critical value, turn off all spark plugs, except for the candles of the second and fifth cylinders.
Contact breaker valves are equipped with replaceable contacts and a capacitor and require regular maintenance, lubrication of the cam and ignition timing corrector, and cleaning of the internal surfaces and cover components.
The electronic ignition system does not require maintenance, except for periodic cleaning and checking the condition of the cover and rotary button of the distributor, as well as lubricating the centrifugal mechanism for adjusting the ignition timing.
Note. Special precautions must be taken when working on or near electronic ignition system components to avoid injury from electric shock. Be aware that dangerously high voltages are present in the secondary circuits of such systems.
Before disconnecting and connecting electrical connectors, turn off the ignition (key - in position OFF) to avoid damage to ignition system components or electrical shock.
Before proceeding with any adjustments to the ignition timing, make sure that the centrifugal mechanism for adjusting the ignition timing in the distributor is working properly.
Replacing breaker contacts
1. Remove the distributor cover, give the slider mounting bolt.
2. Remove the slider.
3. Loosen the contact screw and disconnect the LV wire from the insulating block on the contacts (see accompanying illustration).
4. Loosen the fixing plate fixing screws about two or three turns. Completely unscrew the screws only if absolutely necessary.
5. Remove the breaker contact assembly from the mounting screw and remove the contacts from the distributor.
6. Disunite an electric socket of the distributor.
7. Give the clamping screw of the HB wire clamp and the screw of the ground wire terminal on the distributor housing. Unscrew the fastening screw on the capacitor case, remove the capacitor assembly with the LV wire and discard it.
8. Install contacts in reverse order.
Note. New breaker contacts must be thoroughly washed in a solvent before installation to remove the anti-corrosion coating from them.
9. Install the capacitor on the distributor and tighten its fastening screw. Follow the correct laying of the HB wire.
10. Put a little high-temperature grease under the heel of the rubbing contact block of the breaker, apply a little grease also to the working protrusions of the cam assembly.
11. Install the new terminal assembly into the breaker base plate and temporarily tighten the mounting screws, making sure the ground wire is properly installed.
12. Rotate the motor so that the rubbing moving contact block is on the cam lobe.
13. Slightly loosen the fixing screws of the fixed contact with a suitable screwdriver and slide the contact plate in the desired direction, achieving a gap of 0.45 ÷ 0.55 mm between the contacts (use a blade-type feeler gauge - a blade of appropriate thickness should pass through the gap with slight resistance). After completing the gap adjustment, tighten the plate fixing screws.
14. Rotate the engine several times and repeat the measurement.
15. Connect the LV wire of the breaker to the insulator block on the distributor wall and reinstall the rev limiter screen, slider and distributor cap.
16. In accordance with the manufacturer's instructions, connect a distributor occupancy meter, a tachometer and a stroboscope to the engine and check the idle speed, occlusion duration and ignition timing settings.
Late Years 4.2L Models Equipped with Fuel Injection (EFI)
The electronic system is practically maintenance free, although it is recommended to periodically remove, clean and check the condition of the distributor cap.
Wipe the distributor cap clean with a soft cloth and carefully inspect it inside and out for cracks. If cracks, signs of excessive burning of the terminals, or wear of the carbon brush are found, replace the rotary knob cover.
The order of removal, check of a condition and installation of the distributor is described in the Section devoted to systems of injection of fuel and management of the engine in the Head Power supply and exhaust systems.