Yeah, the monthly fuel pump thread, but I do have some questions and need some guidance:
Fuel pump not coming on with ignition on 1987 LX Mustang.
1. Jumpered test connector in engine bay and pump comes on. So pump is good.
2. Jumpered test connector and verified fuel pump relay is clicking and relay at ECM is clicking. Pump comes on.
3. Ignition on and no jumper on test port. Checked voltages at intertia switch and there is 12V present in and out.
4. Ignition on and no jumper at test port. Checked voltage at red wire on top of fuel injector and 12V is present.
So I’m thinking since the fuel pump relay is clicking on and the EEC relay is clicking on when the test port is jumpered that I have a bad ECM. The ECM is not switching ground on for some reason? Does this sound right?
Thoughts?
Thanks!!
**UPDATE**
So I did finally get this going. Found a short caused by the fuel level slosh module. Removed the slosh module. Also, found my ignition switch was broken. Replaced that. Finally, found flakey ground readings at pins 40 & 60 at the ECM. Found one of the wires grounded to a screw near the headlight and the other not connected to anything. I ended up connecting them both to the ECM ground at the cylindrical connector at the shock tower. The fuel pump fired right up after this with the key on. I was able to start the car and drive it around for about an hour with no issues. The only question I have now is the ground connection at pin 20 on the ECM. This ground is screwed in to the chassis in the kick panel. Should pin 20 go to the ECM ground at the shock tower as well? It would be connected directly to the battery ground there. Is that recommended?
**UPDATE 2**
Grounding questions solved. Pin 20 is grounded to the chassis at the kick panel. Pins 40 & 60 go to the cylindrical ground connection at the shock tower where it is directly connected to the battery negative terminal.
Fuel pump not coming on with ignition on 1987 LX Mustang.
1. Jumpered test connector in engine bay and pump comes on. So pump is good.
2. Jumpered test connector and verified fuel pump relay is clicking and relay at ECM is clicking. Pump comes on.
3. Ignition on and no jumper on test port. Checked voltages at intertia switch and there is 12V present in and out.
4. Ignition on and no jumper at test port. Checked voltage at red wire on top of fuel injector and 12V is present.
So I’m thinking since the fuel pump relay is clicking on and the EEC relay is clicking on when the test port is jumpered that I have a bad ECM. The ECM is not switching ground on for some reason? Does this sound right?
Thoughts?
Thanks!!
**UPDATE**
So I did finally get this going. Found a short caused by the fuel level slosh module. Removed the slosh module. Also, found my ignition switch was broken. Replaced that. Finally, found flakey ground readings at pins 40 & 60 at the ECM. Found one of the wires grounded to a screw near the headlight and the other not connected to anything. I ended up connecting them both to the ECM ground at the cylindrical connector at the shock tower. The fuel pump fired right up after this with the key on. I was able to start the car and drive it around for about an hour with no issues. The only question I have now is the ground connection at pin 20 on the ECM. This ground is screwed in to the chassis in the kick panel. Should pin 20 go to the ECM ground at the shock tower as well? It would be connected directly to the battery ground there. Is that recommended?
**UPDATE 2**
Grounding questions solved. Pin 20 is grounded to the chassis at the kick panel. Pins 40 & 60 go to the cylindrical ground connection at the shock tower where it is directly connected to the battery negative terminal.
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