No power to the fuel pump
Jun 13, 2021 | 07:02 AM
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No power to the fuel pump
This is what I got. 93 4x4 pick up. it will crank over but I'm getting no fuel. I check the relay under the hood it's good got to the circuit relay in the passenger side panel it's good. I get 12v to the connector at the fuel pump when I jump the diagnostic box,but no power with out jumping it. I just replaced the fuel pump in it as well. Any advice would be appreciated. Also I have traced the wires from the fuel pump back to the main relay no broken wires.
Jun 13, 2021 | 11:49 AM
#2
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From: Chiloquin, OR
Did you check the switch in AFM that activates the COR?
Will the truck start, I mean start running normally, with the jumper for the fuel pump in?
While you may have +12VDC at the fuel pump, how's the ground for it? How about for the COR? For the ECU? Those last two are right there under the kick panel with them. Voltage is important to have, but ground is just AS important. Since all those are body grounds, how's the ground from the body to the battery negative? That means both ends. The one attached to the body, usually in front of the battery, right behind the headlight, AND the end attached to the terminal of the battery. Clean, bare, shiney, metal touching clean, bare, shiney, metal.
Quite often, cables that go to battery terminals can corrode inside the insulation. Regular, liquid filled, lead-acid batteries can, and do, outgas an acid mist, that can settle onto open ended wires, corroding the wires down inside the insulation. The copper strands can then break apart, causing an open, that's indetectable visually. For some reason, Toyota goes cheap on the battery terminals. The RIGHT way to do it is to use a wire that ends in a o-ring where it connects to the terminal, with the end of the wire, where it crimps to the o-ring, covered in heatshrink. They should also never have gotten away from the heavy, lead, terminals. Those little, thin, metal loops are no good. Just my opinion, but my entire working life was a Radar Technician. I, personally, prefer the Optima type "gel-cell" batteries, as they don't outgas the acid mist like the regular, lead-acid batteries do. No need to check water levels, either.
I also much prefer the Marine type terminals, the lead ones with a screw post sticking up from them. Then, I can make the wires that attach to them correctly, and they just slip down onto the screw post. Easy on, easy off, and MUCH more environmentally secure.
Also, the ground point for the fuel pump, which is on top of the fuel "hanger". the metal plate the fuel pump hangs down into the tank on. Make sure the ground point isn't corroded, or broken. IIRC, it's under a clear, rubber cap on top of the hanger. You can pull the rubber piece back, and put one meter lead on the terminal revealed. Place the other on a clean, bare, shiney, piece of metal on the body, or the frame. If it's open, IE infinity ohms, it's bad. It shouldn't be ANY more than 1 ohm, preferably far less.
Good luck, and give us a heads up with what you find, good or bad.
Pat☺
Will the truck start, I mean start running normally, with the jumper for the fuel pump in?
While you may have +12VDC at the fuel pump, how's the ground for it? How about for the COR? For the ECU? Those last two are right there under the kick panel with them. Voltage is important to have, but ground is just AS important. Since all those are body grounds, how's the ground from the body to the battery negative? That means both ends. The one attached to the body, usually in front of the battery, right behind the headlight, AND the end attached to the terminal of the battery. Clean, bare, shiney, metal touching clean, bare, shiney, metal.
Quite often, cables that go to battery terminals can corrode inside the insulation. Regular, liquid filled, lead-acid batteries can, and do, outgas an acid mist, that can settle onto open ended wires, corroding the wires down inside the insulation. The copper strands can then break apart, causing an open, that's indetectable visually. For some reason, Toyota goes cheap on the battery terminals. The RIGHT way to do it is to use a wire that ends in a o-ring where it connects to the terminal, with the end of the wire, where it crimps to the o-ring, covered in heatshrink. They should also never have gotten away from the heavy, lead, terminals. Those little, thin, metal loops are no good. Just my opinion, but my entire working life was a Radar Technician. I, personally, prefer the Optima type "gel-cell" batteries, as they don't outgas the acid mist like the regular, lead-acid batteries do. No need to check water levels, either.
I also much prefer the Marine type terminals, the lead ones with a screw post sticking up from them. Then, I can make the wires that attach to them correctly, and they just slip down onto the screw post. Easy on, easy off, and MUCH more environmentally secure.
Also, the ground point for the fuel pump, which is on top of the fuel "hanger". the metal plate the fuel pump hangs down into the tank on. Make sure the ground point isn't corroded, or broken. IIRC, it's under a clear, rubber cap on top of the hanger. You can pull the rubber piece back, and put one meter lead on the terminal revealed. Place the other on a clean, bare, shiney, piece of metal on the body, or the frame. If it's open, IE infinity ohms, it's bad. It shouldn't be ANY more than 1 ohm, preferably far less.
Good luck, and give us a heads up with what you find, good or bad.
Pat☺
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