Fuel Pump Relay
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From: Kingman az
Fuel Pump Relay
I have a 1986 Ranger 2.9 with no spark. I have tracked it down to the Fuel Pump Relay. With the ignition in the Run position, on the EEC Relay there is power to both the yellow and red wires, but on the Fuel Pump Relay there is power to the yellow but not to the red. All the fuses and fusable links have been checked, as well as the power and ground to the EEC Relay. I have followed a test jumpering the tan/light green to ground on the self test connector, which causes a real soft buzz coming from the front part of the engine. When I jumper the yellow to red on the relay, it clicks, but by this point the battery was too weak when I tried a test start. While it's charging, I figured I'd ask why would there be no power to the red wire on the Fuel Pump Relay?
Last edited by JayBirdAz; Jan 29, 2023 at 04:14 PM.
Welcome to the forum
Fuel pump relay has no connection to "no spark"
The EEC relay is activated by Key on, and thats where the "red" wire comes from
In 1986 the EEC relay has a dark Blue wire that comes out to a Fusible link, 20ga, and that's connected to a RED wire that splits off, this red wire powers the EEC(computer), Fuel injectors, most solenoids, including IAC Valve and fuel pump relay
Fuel pump relay is control by the Computer, it grounds it, tan/green wire, to activate it, its only activates for 2 seconds each time key is turned from off to on, it won't activate again until engine RPMs are above 400 or unless you turn key off and on again
Cranking speed is 200rpm, just FYI
Spark is powered by ignition switch, red/green wire, runs to TFI module and Coil
1983 to 1994 Rangers used a separate spark system, doesn't need "the computer" to work, just FYI
50/50 test is the easiest test to do with a crank but No Start
Spray fuel into the engine: gasoline, Quick Start(ether), carb cleaner, brake cleaner, ect..................
Try to start it
If it starts, runs, and dies then fuel supply is the issue
If it doesn't start/fire then Spark is the issue
50/50 no guessing, instant results
Test has been around since the 1890's and the first gasoline engines, lol, so time tested
Fuel pump relay has no connection to "no spark"
The EEC relay is activated by Key on, and thats where the "red" wire comes from
In 1986 the EEC relay has a dark Blue wire that comes out to a Fusible link, 20ga, and that's connected to a RED wire that splits off, this red wire powers the EEC(computer), Fuel injectors, most solenoids, including IAC Valve and fuel pump relay
Fuel pump relay is control by the Computer, it grounds it, tan/green wire, to activate it, its only activates for 2 seconds each time key is turned from off to on, it won't activate again until engine RPMs are above 400 or unless you turn key off and on again
Cranking speed is 200rpm, just FYI
Spark is powered by ignition switch, red/green wire, runs to TFI module and Coil
1983 to 1994 Rangers used a separate spark system, doesn't need "the computer" to work, just FYI
50/50 test is the easiest test to do with a crank but No Start
Spray fuel into the engine: gasoline, Quick Start(ether), carb cleaner, brake cleaner, ect..................
Try to start it
If it starts, runs, and dies then fuel supply is the issue
If it doesn't start/fire then Spark is the issue
50/50 no guessing, instant results
Test has been around since the 1890's and the first gasoline engines, lol, so time tested
Last edited by RonD; Jan 27, 2023 at 04:23 PM.
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