Hi there!It sounds like a distributor failure.Nissan usues a crank position sensor inside the distributor.Once it goes bad you have no choice but to replace the distributor.Here is some information.
Service consists of inspection of the distributor cap, rotor, and ignition wires, replacing when necessary. These parts can be expected to last for at least 40,000 miles (52,000 km). In addition, the reluctor air gap should be checked periodically.
Fig. 1: Removing the distributor cap hold-down screws
Fig. 2: Removing the distributor cap
Fig. 3: View of the coil wire installed
Fig. 4: Removing the coil wire
Fig. 5: Removing the coil dust boot cover
See Figures 6 and 7
The distributor cap is held on by two clips. Release them with a screwdriver and lift the cap straight up and off, with the wires attached. Inspect the cap for cracks, carbon tracks, or a worn center contact. Replace it if necessary, transferring the wires one at a time from the old cap to the new.
Pull the ignition rotor (not the spoked reluctor) straight up to remove. Replace it if its contacts are worn, burned, or pitted. Do not file the contacts. To replace, press it firmly onto the shaft. It only goes on one way, so be sure it is fully seated.
Before replacing the ignition rotor, check the reluctor air gap. Use a non-magnetic feeler gauge. Rotate the engine until a reluctor spoke is aligned with the pick-up coil (either bump the engine around with the starter, or turn it with a wrench on the crankshaft pulley bolt). The gap should measure 0.008-0.16 in. (0.20-0.40mm) through 1978 vehicles, or 0.012-0.020 in. (0.30-0.50mm) for 1979-80 vehicles. Adjustment, if necessary, is made by loosening the pick-up coil mounting screws and shifting its position on the breaker plate either closer to or farther from the reluctor. On 1979-80 models, center the pick-up coil (ring) around the reluctor. Tighten the screws and recheck the gap.
Inspect the wires for cracks or brittleness. Replace them one at a time to prevent crosswiring, carefully pressing the replacement wires into place. The cores of electronic wires are more susceptible to breakage than those of standard wires, so treat them gently.
Fig. 6: Air gap adjustment-1976-77 Calif. and 1978 vehicles
Fig. 7: Air gap adjustment-1979-80
See Figure 8
Remove the distributor cap then remove the rotor retaining screw.
Adjust the air gap between the reluctor and stator. The air gap should be 0.012-0.020 in. (0.30-0.50mm).
Inspect the wires, cap and rotor as outlined in the earlier procedure.
Fig. 8: Air gap adjustment-1981-86 carbureted models
PICK-UP COIL AND RELUCTOR REPLACEMENT
See Figures 9, 10 and 11
The reluctor cannot be removed on some early models. It is an integral part of the distributor shaft. Non-removable reluctors can be distinguished by the absence of a roll pin (retaining pin) which locks the reluctor in place on the shaft.
To replace the pick-up coil on all 1976-78 models:
Remove the distributor cap by releasing the two spring clips. Remove the ignition rotor by pulling it straight up and off the shaft.
Disconnect the distributor wiring harness at the terminal block.
Remove the two pick-up coil mounting screws. Remove the screws retaining the wiring harness to the distributor.
Remove the pick-up coil. When replacing the the pick-up coil leave the mounting screws slightly loose to facilitate air gap adjustment.
To replace the reluctor on models with a roll pin:
Remove the distributor cap, ignition rotor and the pick-up coil.
Use two pry bars or equivalent to pry the reluctor from the distributor shaft. Be extremely careful not to damage the reluctor teeth. Remove the roll pin.
To install; press the reluctor firmly onto the shaft. Install a new roll pin with the slit facing away from the distributor shaft. Do not re-use the old roll pin.
Fig. 9: Electronic control unit connections-upper view 1976-77; lower view 1978
Fig. 10: Removing the pick-up coil-1976-78
Fig. 11: Roll pin installation-1976-78
See Figures 12, 13 and 14
Remove the distributor cap. Remove the ignition rotor by pulling the rotor straight up and off the shaft.
Use a pair of needle nose pliers to disconnect the pick-up coil spade connectors from the ignition unit. Do not pull on the pick-up coil wires themselves.
Remove the toothed stator and the ring magnet underneath it by removing the three mounting screws.
Remove the reluctor by prying it from the distributor shaft with two small pry bars or a small puller. Be careful not to damage any of the reluctor teeth. Remove the roll pin.
Remove the screw retaining the pick-up coil wiring harness to the distributor. Remove the pick-up coil.
Install the pick-up coil into place in the distributor body. Replace the wiring harness retainer.
Press the reluctor firmly into place on the shaft. Install a new roll pin with the slit in the pin parallel to the flat on the shaft.
Install the magnet and stator, and center the stator around the reluctor. Check the air gap.
Press the pick-up coil spade connectors onto the ignition unit terminals with your fingers. The proper connections can be determined from the color code marked on the grommet. Replace the ignition rotor and the distributor cap.
Fig. 12: Roll pin installation-1979-86
Fig. 13: Connecting the pick-up coil terminal-1979-80
Fig. 14: Removing the reluctor-1979-86
RELUCTOR AND IC IGNITION UNIT
On all fuel injected models (VG30i and Z24i) a crank angle sensor in the distributor is used.
Remove the distributor cap and rotor. The rotor is held to the distributor shaft by a retaining screw, which must be removed.
Remove the wiring harness and the vacuum controller from the housing.
Using 2 flat bladed screwdrivers, place one on each side of the reluctor and pry it from the distributor shaft.
When removing the reluctor, be careful not to damage or distort the teeth.
Remove the roll pin from the reluctor.
To remove the IC unit, mark and remove the breaker plate assembly then separate the IC unit from it. Be careful not to loose the spacers when you remove the IC unit.
Install the IC unit to the breaker plate assembly.
Install the wiring harness and the vacuum controller to the distributor housing. When you install the roll pin into the reluctor position the cutout direction of the roll pin in parallel with the notch in the reluctor. Make sure that the harness to the IC ignition unit is tightly secured, then adjust the air gap between the reluctor and the stator.
FUEL INJECTED ENGINES
All fuel injected models (VG30i and Z24i) utilize a crank angle sensor in the distributor. The only service that is possible is to replace the distributor cap and rotor, as necessary. Removal and installation of the distributor assembly is covered in Engine & Engine Overhaul of this repair guide.
The distributor cap is held on by two screws. Release them with a screwdriver and lift the cap straight up and off, with the wires attached. Inspect the cap for cracks, carbon tracks, or a worn center contact.
Pull the ignition rotor straight up to remove. Replace it if its contacts are worn, burned, or pitted. Do not file the contacts. To replace, press it firmly onto the shaft. It only goes on one way, so be sure it is fully seated.
Install the distributor cap and tighten the two screws.