RAD4Runner
Senior Member
PLEASE DOUBLE CHECK WIRE COLORS AND SCHEMATIC AGAINST YOUR OWN FSM BECAUSE SOME TRUCK WIRING MAY TRANSITION DURING A YEAR.
How Circuit Opening Relay Works - 22R-Eliable
The relay prevents unwanted, unsafe fuel flow (i.e., in case of an accident when fuel line ruptures, engine stalls, airflow stops and COR interrupts power to the fuel pump). COR is the thing that you'd hear click behind the glovebox when you're trying to start a first gen 4Runner. However, it does not affect cranking system.
(In 1986 Runner) COR is located behind glove compartment near speaker and blower motor. Someone had posted about moisture in COR. Possible because:
a) It's near some body seams,
b) Its below where windshield joins the frame- there could be a leak there, and
c) It's near right side wheelwell, where there could be leaks. There are 2 grommets there. One for engine harness, one for antenna. Check for leaks.
MAF-COR-Fuel pump circuit is below. Circuit Opening Relay (COR) has two normally-open contacts (open when no power is applied). Coil 1 of COR is energized by IGN switch while in START position. Once airflow is established due to combustion, MAF contacts provide ground to coil 2 of COR, keeps COR energized and its contacts closed, even after IGN switch is released.
1986 SCHEMATIC
1988 SCHEMATIC
To bypass AFM contacts Jump terminals of Fuel Pump Check Connector* (below) while ignition is on.
Coil 2 of COR will be connected to ground, C.O.R. will click, and good fuel pump with good connections will run. Fuel will flow IF fuel lines are not clogged.
If you suspect Air Flow Meter malfunction, where you hear, feel and smell combustion ONLY WHILE holding ignition switch in "START" position but STOPS WHEN YOU RELEASE THE KEY this is a good test.
Also a good test for C.O.R. coil 2 and contact, as well a fuel pump and connections.
* On 1986 22R-E, brown and green wires lead to connector. On 1988 Blue and BLACK. 1985, 1987 unknown to me.
PLEASE DOUBLE CHECK WIRE COLORS AND SCHEMATIC AGAINST YOUR OWN FSM BECAUSE SOME TRUCK WIRING MAY TRANSITION DURING A YEAR.
Keywords: C.O.R. circuit-opening, how it works, circuitopeningrelay
How Circuit Opening Relay Works - 22R-Eliable
The relay prevents unwanted, unsafe fuel flow (i.e., in case of an accident when fuel line ruptures, engine stalls, airflow stops and COR interrupts power to the fuel pump). COR is the thing that you'd hear click behind the glovebox when you're trying to start a first gen 4Runner. However, it does not affect cranking system.
(In 1986 Runner) COR is located behind glove compartment near speaker and blower motor. Someone had posted about moisture in COR. Possible because:
a) It's near some body seams,
b) Its below where windshield joins the frame- there could be a leak there, and
c) It's near right side wheelwell, where there could be leaks. There are 2 grommets there. One for engine harness, one for antenna. Check for leaks.
MAF-COR-Fuel pump circuit is below. Circuit Opening Relay (COR) has two normally-open contacts (open when no power is applied). Coil 1 of COR is energized by IGN switch while in START position. Once airflow is established due to combustion, MAF contacts provide ground to coil 2 of COR, keeps COR energized and its contacts closed, even after IGN switch is released.
1986 SCHEMATIC
1988 SCHEMATIC
To bypass AFM contacts Jump terminals of Fuel Pump Check Connector* (below) while ignition is on.
Coil 2 of COR will be connected to ground, C.O.R. will click, and good fuel pump with good connections will run. Fuel will flow IF fuel lines are not clogged.
If you suspect Air Flow Meter malfunction, where you hear, feel and smell combustion ONLY WHILE holding ignition switch in "START" position but STOPS WHEN YOU RELEASE THE KEY this is a good test.
Also a good test for C.O.R. coil 2 and contact, as well a fuel pump and connections.
* On 1986 22R-E, brown and green wires lead to connector. On 1988 Blue and BLACK. 1985, 1987 unknown to me.
PLEASE DOUBLE CHECK WIRE COLORS AND SCHEMATIC AGAINST YOUR OWN FSM BECAUSE SOME TRUCK WIRING MAY TRANSITION DURING A YEAR.
Keywords: C.O.R. circuit-opening, how it works, circuitopeningrelay
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