[nippaz]

During the pandemic, I let my 2007 Taco, Double Cab, 4X4 V6 sit on the driveway. Well, to be completely honest, it sat a little before the pandemic started. So now I need to drain the gas and change the oil. I learned the hard way you can not siphon the gas because of measures put in place to prevent thievery. An internet search has suggested to jump the relay and use the fuel pump to pump out the gas.

I figured this was easier than dropping the fuel tank so I embarked upon this journey. Research said 99.9% of relays have 4 pins and they are marked 30, 85, 86, and 87. Furthermore, the diagram is also listed on the side of them. Well, a struggle and a half later, I safely removed the Fuel Pump Relay and SURPRISE!!!! it's 5 pins with no markings, and no diagrams.

I start doing research on the Denso 90084 - 98032 to see if I could find a pin diagram as I am supposed to connect pins 30 and 87 to have the fuel pump pump out my gas. Well, as it would have it, no such diagram exists. I did however stumble upon this diagram on a Toyota 4 Runner forum

I disconnect the front fuel line from the quick disconnect with yellow tabs. Attach a 3/8" rubber tube to the metal tube and run it into a gas can.

I checked for continuity and found continuity across 30 and 87a with resistance across 85 and 86. Everything checks out! So I disconnect negative battery terminal, stick in a paperclip, mistakenly across 87 and 87a, reconnect battery terminal, turn key to 'On' and nothing. I realize my mistake and repeat the process but this time, paperclip is across 30 and 87. Key to 'On' and still nothing.

To make sure I connected to the correct fuel line, I disconnect the other quick disconnect with yellow tabs and put a cup under that, turned my key to 'On' hoping it would prime, but nothing happens. I leave both tubes disconnected and jump pins 30 and 87 again, and nothing comes out of either tube.

Am I doing this wrong?

Alternatively, I have about 1/8 of a tank of gas left, if I can't get the gas drained, I may end up filling the remaining 3/4 tank with 91 octane gas, hoping it would slosh around and normalize enough to drive.

Your thoughts?

Thank you.

 

[Enola Gaia]

Welcome to CT ... I'm not sure this sort of thing has been discussed before here on CT.

First ... Did you ever hear the fuel pump activate when you bridged the various wires?

 

[nippaz]

Hi there. Thank you for the response and your hospitality.

As for your question, I don't recall hearing the pump activate. I read elsewhere that I may turn on the fuel pump by jumping the Open Circuit Relay. I just didn't want to bypass all sorts of relays before I asked some questions.

Thank you.

 

[Enola Gaia]

Here (attached) are the 2007 starting and 1GR engine control wiring diagrams.

I'm not sure bridging pins on the Fuel Pump Relay will work to activate the fuel pump.

I can't figure out how the pump relay, Circuit Opening Relay, EFI Relay, and the ECM are supposed to interact when the ignition switch is in the on position.

I suspect the Circuit Opening Relay isn't activating, and the Fuel Pump Relay isn't getting any current, but I can't prove it.

It also seems to me the yellow-with-red-stripe wire from the Fuel Pump Relay to the ECM has to be connected for the FPR to operate. If I'm reading the diagram right, the FPR activation circuit grounds back to the ECM. Toyota uses negative switching - if there's no ground, the circuit stays dead.

 

[nippaz]

Well thank god I'm not the only one stumped by this. I do appreciate you helping. If I can find the relay pin out for the Circuit Opening Relay, I would definitely try that and report back. I think I read somewhere else to take B+ to FP(??) I forget.

Short of dropping the fuel tank. Do you recommend a different method of draining the fuel tank? What are your thoughts of me filling my tank with 91 octane and just starting it with 1/8 tank of expired gas in the tank?

Thank you

 

[Enola Gaia]

This thought may be as stupid as it is off-the-wall ...

I'm still not 100% certain how to translate the 4Runner diagram pin numbers into the Engine Control diagram pin numbers. Under what I think is the most probable interpretation ...

Is it possible you fried the resistor when you mistakenly bridged pins using the paper clip the first time?

 

[nippaz]

The thought had crossed my mind and it worried me quite a bit. However I bridged 87 to 87a, according to the pin diagram, it basically bridged between 2 potential gate positions. Normally open to normally closed. And the resistor was not in place as I used the paperclip to bridge a makeshift closed switch. The relay was removed throughout that process. With you confirming that the fuel pump does not prime with the key in the 'On' position, I'm further comforted in knowing the fuel pump may not be fried.

I read resistor as relay....when i said resistor in my above post, I really meant relay.

With this new information, where and which resistor may I have fried?

 

[Enola Gaia]

Look at the Engine Control wiring diagram, page 79.

I was referring to the Fuel Pump Resistor connected to the FPR via the black-with-yellow-stripe wire at the FPR pin #5. I can't figure out what purpose the resistor is supposed to serve. If my translation of the 4Runner diagram was correct I think you mistakenly bridged the sub-circuits on both sides of the resistor at once. However, if the FPR didn't activate while these two pins were bridged it seems (to me) to indicate the FPR wasn't getting any current from the Circuit Opening Relay in the first place.

This is the main reason why I'm totally confused about what's going wrong where.

 

[nippaz]

Hmmm...I see that resistor. Where would it physically be? How can I test it? And how would I turn it on to drain the gas tank?

Thank you for your help.

 

[Enola Gaia]

Unfortunately, I don't know. I don't even know if it's possible to ruin a resistor by putting full current on both ends of it.

As I mentioned, I can't figure out what the parallel sub-circuit with the resistor is supposed to do. Without understanding that, I'm reluctant to suggest applying direct 12V power to the fuel pump line at connector IB1 (left kick panel) just to see if the pump works at all.

If the FPR isn't activating (clicking) at all, it may not be getting any power. Check the fuses shown on the diagrams I posted. It could also mean that something 'upstream' in the control path (e.g., the Circuit Opening Relay) isn't working.

The fuel pump resistor is located in the engine bay somewhere behind your port side (driver side) headlight. I'm attaching a routing diagram from the 2007 FSM to illustrate the location. Item "F11" is the resistor.

Hope this helps ...

 

[nippaz]

Thank you for your help. I'll look at the resistor and hope it hasn't failed. If the relay diagram is correct, big if, but I've cross checked with many different diagrams, I'm still uncertain how bridging pin 87 to 87a would cause a short. I've looked for the Fuel Pump fuse and could not find it, unless it's buried/bundled with another accessory.

 

[Enola Gaia]

There isn't a separate fuse for the fuel pump.

If I'm reading the engine control diagram correctly, the power that gets fed to the fuel pump comes through the 20A EFI fuse.

 

[nippaz]

Thank you. I'll check that fuse in the morning and report back.