1989 E-150 5.0 EFI Fuel Pump Relay
#1
1989 E-150 5.0 EFI Fuel Pump Relay
Hi All
My schematics show the output of the Fuel Pump Relay is supposed to be 12v when the computer closes the relay. This occurs when the Ignition switch is put in the START or RUN position. On my setup this indeed occurs but the 12v is only there momentarily when I switched to RUN. I'm told that the 12v reappears full time as soon as the engine starts and the ignition switch returned to RUN. Unfortunately my engine does not start, and I cannot find any data to support this statement.
Is this actually the way this circuit is supposed to work, or is the computer crapping out by not holding the Fuel Pump Relay energized?
My schematics show the output of the Fuel Pump Relay is supposed to be 12v when the computer closes the relay. This occurs when the Ignition switch is put in the START or RUN position. On my setup this indeed occurs but the 12v is only there momentarily when I switched to RUN. I'm told that the 12v reappears full time as soon as the engine starts and the ignition switch returned to RUN. Unfortunately my engine does not start, and I cannot find any data to support this statement.
Is this actually the way this circuit is supposed to work, or is the computer crapping out by not holding the Fuel Pump Relay energized?
#2
Join Date: Jun 2006
Location: Ottawa, Ontario
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Yes the computer only energizes the fuel pumps for a second or so when the key turned to run, they are also energized while the starter is being cranked of course.
For diagnostics find the EEC Test Connector and ground the fuel pump test lead, now the pumps will run continuously with the key in the run position.
For diagnostics find the EEC Test Connector and ground the fuel pump test lead, now the pumps will run continuously with the key in the run position.
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