Mechanics

FUEL PUMP CIRCUIT

1988 Ford Ranger

Electrical problem
1988 Ford Ranger 6 cyl Two Wheel Drive Automatic 122773 miles

I have a code reader and it says " no ground to the fuel pump circuit) (code 95) Does that mean the computer is bad or what? I have checked the relay. It is fine, ( this vehicle has 2 fuel pumps and it is unlikely they would both go out at once) Anyway I have spark, so something with the fuel pump circiut I am guessing. I was told that the CPU was the ground for the fuel pump and the injectors as well. What do you suggest?

Thanks, Greg
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Greg1951nc
February 23, 2009.




Hello .. thanks for the donation .. much appreciated

Hope this helps .. let me know if you need anymore information

When ignition is turned on, EEC power relay is energized, closing its contacts. Power is provided to both fuel pump relay and timing device in EEC module. Fuel pump runs through contacts of fuel pump relay. If ignition is not turned on within one second, timing device in EEC module will create an open ground circuit.
Opening ground circuit of fuel pump relay de-energizes fuel pump. This circuit provides for pre-pressurization of fuel system. When ignition switch is turned to "START" position. EEC module operates fuel pump relay to provide fuel for starting engine while cranking.
If vehicle is involved in a collision, inertia switch will stop fuel flow. Engine will run until residual fuel is exhausted. If inertia switch has been tripped, switch must be reset before vehicle can be restarted.
Inertia switch location on Bronco II and Ranger is on floorboard to right of transmission hump. Aerostar inertia switch is located in the right kick panel. On "E" series, switch location is passenger's side cowl panel, forward of right front door. On Bronco and "F" series, switch location is on left kick panel, near emergency brake pedal.
To reset inertia switch, turn ignition off. Check for fuel leaks in engine compartment, fuel lines, and at tank. If no leaks are found, reset switch by depressing button on top of inertia switch. If gasoline fumes or liquid are present, DO NOT reset switch.
A high pressure pump is used on vehicles with MPFI equipped engines. A pressure relief valve, mounted internally, protects against over-pressurization of system if fuel flow is restricted.
Aerostar has an in-tank high pressure pump. All other models use a frame mounted high pressure pump.
A low pressure electric in-tank fuel pump is used on all models except Aerostar, to provide pressurized fuel to inlet of high pressure pump, reducing pump noise and pump overheating problems.

FUEL INJECTORS
On MPFI and SEFI engines, each cylinder has a solenoid-operated injector which sprays fuel toward back of each intake valve. Each injector is energized through ignition circuit and grounded through ECA to complete circuit. Injectors deliver 1/2 the amount of fuel required for an operating cycle each time they open (twice per cycle).
On all fuel injected models, the ECA controls length of time each injector is open. The "open" time of injector governs amount of fuel delivered.
FUEL PUMP RELAY
Fuel pump relay and ignition is activated by ECA when the ignition switch is in the "ON" or "CRANK" positions. When ignition is turned on, the relay is activated to supply initial line pressure to system.


http://www.2carpros.com/forum/automotive_pictures/266999_pump_8.jpg


Dave H
Feb 23, 2009.


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