My Notes
Firing order dist – 1 5 3 6 2 4 counter clockwise…
Get a 9 volt battery and some jumper leads. Check each injector including the cold start by pulling the plug and touching the terminals with the +and – from the 9 volt. You should hear them click on and off. No click = no good. Done.
Remove the distributor and spray the guts with PB blaster or Sea Foam. You should be able to move the breaker plate with your fingers and it should return freely. If not it is probably junk. If OK then use a vacuum gun to test the diaphragm, these usually go bad.
Disconnect the cold start valve to see if the backfiring stops, it could be staying or stuck on.
Backfiring in the exhaust means unburned fuel and or late timing.
2 crossed plug wires will run just a little rough but backfire occasionally even at idle. Recheck your plug wires and firing order.
Check your Thermotime switch per the fsm ohm test.
Spend your money on tools not unnecessary parts.
Using the Timing Light
FSM says – 10 degrees before top dead center
Headlight combo switch
This is how the schematic of the Combo Switch works: In position Off, no contacts are made. In Position 1, only contacts 1 and 2 are made. In position 2, contacts 1 & 2 are made, and contacts 19 and 20 are made. Contacts 1 & 2 are for your parking/running lights. Contacts 19 & 20 are for your headlights. 12VDC+ comes into the switch on the White wire with Red strip (W/R) at contact 19. This is regardless of key position (unswitched source). The 12VDC+ goes out the Red wire (R) at contact 20. The Red wire goes to the fuse box where it is split between two fuses. The fuse with the Red wire goes out to the right headlight. The Red wire with Yellow strip (R/Y) goes out to the left headlight.
There are two possible return paths for the headlights. One is a Red wire with Black strip (R/B), and the other is a Red wire with White strip (R/W). The return path is determined by the position of the high/low beam switch that is integrated into the turn signal switch. The switch will make contact with either the R/B or R/W wire. The other contact in the switch is tied to ground. This ground ties back over to the Combo Switch and goes out as a Black (B) wire.
