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Hello all! Proud owner of an 87 ford ranger."Rusty" was my first truck and lately he's been having problems. Was driving him in the bumpy fields 3 years ago on the farm when it suddenly died and I haven't got him started since. Replaced fuel pump, fuel pump relay, fuel tank, bypassed the inertia switch, now I can get the pump to run when I bypass the two pins. But I got no ground or power from the ECM on the relay connector when cranking, and no power on the wire that runs to the inertia switch with relay connected. Also tried to run codes but got nothing not even the all clear.So I'm thinking the next thing to replace would be the EEC which might have got fried when testing relay circuits. However I took it apart and no visible damage and only a faint smell. But even if the relay wasn't hooked up to the EEC shouldnt it still engage?
The EEC runs the fuel injection, and the fuel pump
The EEC relay, Brown base, in the engine bay is activated with Key ON
EEC Relay then sends power to the EEC, of course, but also to injectors and Fuel Pump Relay(green base)
The EEC Grounds the fuel pump relay to activate it, pin 22, so it doesn't send 12v to relay, it should ready have 12v with key on, so grounding the relay turns it on
2nd drawing shows the Slot for Fuel Pump
If you GROUND that slot, battery negative, then when you turn on the key fuel pump relay should close and fuel pump should come on
If you unhook the ground FP relay will open
If thats not working the FP relay has no 12volts from EEC relay
There are 2 or 3 capacitors in the EEC, round cylinders, blue or black, they can leak and fail and can cause no fuel pump relay activation, so have a close look at those
The EEC runs the fuel injection, and the fuel pump
The EEC relay, Brown base, in the engine bay is activated with Key ON
EEC Relay then sends power to the EEC, of course, but also to injectors and Fuel Pump Relay(green base)
The EEC Grounds the fuel pump relay to activate it, pin 22, so it doesn't send 12v to relay, it should ready have 12v with key on, so grounding the relay turns it on
2nd drawing shows the Slot for Fuel Pump
If you GROUND that slot, battery negative, then when you turn on the key fuel pump relay should close and fuel pump should come on
If you unhook the ground FP relay will open
If thats not working the FP relay has no 12volts from EEC relay
There are 2 or 3 capacitors in the EEC, round cylinders, blue or black, they can leak and fail and can cause no fuel pump relay activation, so have a close look at those
Alrighty. New EEC came in tried it out, didn't help. Grounded the slot you told me about I can hear and feel a clicking in the brown relay which I assume is the EEC relay and fuel pump does not come on. What does that mean.
I had issues of not getting fuel pressure. My issue was with the connections with the EEC relay. Removed and plugging it back in several times and haven't had issues since.
If you leave the key ON the brown relay(EEC) should be closed
If you ground the slot in the OBD1 connector the GREEN relay should "click" closed, that's the Fuel pump relay and fuel pumps should come on
The EEC relay sends 12volts to the FP relay but its not grounded, computer does that AFTER engine starts up
The Slot over rides the computer, and grounds the FP relay full time
09-18-2021
