No power to fuel pump. Power up to open circuit relay. My 1996 tacoma 2.4 liter has this problem but there is power even getting to the top of the tank. I'm thinking the air dlow meter is bad since the last time it ran my friend said he was in the rain and drove through a huge puddle. Its been dead since like a month now. Engine turns over fine but theres no power to the pump. Checked the relays and the fuses and the pump and even the circuit opening relay under the dash. HELP please I'm about to just hook it up to the ignition key and be done with it but I would rather hook it up right.

https://www.tacomaworld.com/threads/1996-fuel-pump-wiring-diagram-or-test-power-to-pump.514659/

This site may help you

To answer your question specifically it would be no. There
is no inertia switch that feeds the fuel pump that can be turned off or reset . The engine control computer turns on a series of two different relays to control power to the fuel pump. When in the start position the circuit opening relay and the fuel pump relay or both energize causing the fuel pump to run at full pressure or fast speed. From there the engine control computer determines which demand is on the fuel pump and either turns off the fuel pump relay and leaves
the circuit opening relay on to supply power through a resistor to slow the pump down for less demand. The EFI main relay is the main supply relay to both of these sub relays. The fuel pump is powered up ultimately by the 20 amp EFI number one fuse. All of these components are located in the fuse box under the hood. If the circuit opening relay is not working it's powered up by the 10 amp
ignition fuse inside the vehicle. It's unlikely it is the 10 amp ignition fuse because that powers up a lot of other things also.

Open the hood and look for the engine control fuse box. On the inside of lid it should tell you which one is the fuel pump relay.

Check the following:
- Listen to the fuel pump noise under the fuel tank.
- Starter signal.
- EFI relay, under the hood fuse and relay box.
- Fuel pump operation and pressure.
- Regulating valve.
- Circuit Opening Relay (COR) under the dash.
- Check for open in harness and connector between circuit opening relay and fuel pump, and fuel pump and body ground





Hope that works. Thank you for visiting Fixya.

Most relays have a diagram on the side showing the terminals by number.
You would take a test light or meter and check the terminals in the fuse box for power and ground. You should have two power wires, one ground from the computer, and the circuit to the pump. Keep in mind the computer grounds the relay for only 3 seconds if the engine does not start.

I'm guessing fuel pump is going. Check for 40 PSI pressure with fuel pressure gauge. Check in engine comaprtment.
Section 10-01: Fuel Tank, Filters, Lines and Electric Fuel Pump 1995 Thunderbird, Cougar Workshop Manual
DESCRIPTION AND OPERATION Fuel Pump, Electric The electric fuel pump:

• Is part of the fuel pump module.
• Is located in an internal reservoir in the polyethylene fuel tank (9002) .
• Is mounted with its inlet at the bottom of the reservoir.
• Is designed to increase satisfactory pump operation during extreme vehicle maneuvers and steep climbs with low fuel levels.
• The high-pressure fuel pump module on the 3.8L SFI and 4.6L-2V engines can supply 60 liters (15.9 gal) of fuel per hour at a working pressure of 269.0 kPa (39 psi).
• The fuel pump module on the 3.8L SC SFI engine can supply 125 liters (29.0 gal) at the same rate and pressure.
• The fuel pump module has an internal check valve to maintain pressure in the system after the engine is shut down.
• The fuel pump module also has an internal release valve to provide protection from too much pressure if fuel flow becomes clogged in the fuel filter (9155) , the fuel line is damaged, or other factors.
• Overpressure is limited to 850 kPa (123 psi) and reduced fuel flow will result if the pressure relief valve is activated.
• The fuel pump module is protected at its inlet by a nylon fuel filter element (9365) which filters contaminants which could plug or damage fuel pump components.
• The fuel filter element simultaneously allows passage of small quantities of water which may accumulate within the tank reservoir.
• The electrical system has a fuel pump control relay in the powertrain control module (PCM) (12A650) which provides power to the fuel pump module through an inertia fuel shutoff switch (IFS switch) (9341) that is normally closed.
• The electrical system provides power to the fuel pump module through two relays:
  • Fuel pump power relay.
  • PCM power relay.

The current path depends on operating conditions.

• When the ignition switch (11572) is OFF, contacts of both relays are open.
• When the ignition switch is first turned to RUN, the PCM power relay energizes and closes its contacts.
• Power is sent to the fuel pump relay and a timing device in the powertrain control module .
• The fuel pump module runs through the contacts of the fuel pump relay.
• If ignition switch is not turned to START, the timing device in the powertrain control module will open ground Circuit 57 after about a second.
• Opening the ground circuit deenergizes the fuel pump relay, which opens its contacts and de-energizes the fuel pump.
• The circuitry provides pre-pressurization of the fuel system.
• When the ignition switch is turned to START, the powertrain control module operates the fuel pump relay to provide fuel while cranking.
• After the engine starts and the ignition switch is ON, power to the fuel pump module is again supplied through the fuel pump relay. The powertrain control module senses engine speed and shuts the fuel pump module OFF by opening the ground circuit to the fuel pump relay when the engine stops or is below 120 rpm.

Look to see if you have power at pin 1 of the circuit opening relay. The C.O. Relay is what powers the fuel pump. If you have power there (a blue wire), you have an open circuit between the relay and the pump.

You have a very common problem. There is rust on top of the fuel tank, and it is shorting your fuel pump power input. Unplug the connector by the tank, and replace the fuse. If it does not blow, my solution is correct. Remove the tank, or remove the bed, to access the top of the tank. Remove the bracket that holds the pump/fuel sending unit and replace it.

I am not positive how the electronics are routed on a later model truck but I had this same problem on my 89' with a 22re. It turned out that the oil pressure sending unit was in the fuel pump circuit so as to not allow the engine to start with no oil pressure. I changed my sending unit and the truck fired right off. Hope this helps.

No power to the fuel pump is a common issue with Toyota Trucks. More than likely, the power wire at the top of the fuel tank sending unit is rusted off. If this is the case, you either need to drop the tank, or remove the bed to replace the sending unit assembly. I have done it both ways, but have found that removing the bed is easier than dropping the tank.