FJ62 No start after dropping fuel tank.

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I dropped my fuel tank (40 gal. aftermarket) to install a new fuel sending unit + fuel gauge.

I used the original fuel sending unit wires and spliced in the new fuel sending unit to wire it to the new aftermarket fuel gauge.
After putting everything back together, the cruiser won't start, its not getting fuel.

In the morning I'd like to do some troubleshooting, figure out if I'm getting power to the fuel pump or if the pump somehow died while messing with the tank.

1. If I turn the key on ACC, should I see 12 volt on the fuel pump wires? Or only when cranking?
2. Did I mess up by using the original fuel sending wires, is it normally telling the ECU something that now it is not?
3. There is no fusing around anything fuel pump right?

Thank you!
 

red66toy

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Maybe you missed a ground wire connection when hooking it all back up at the fuel pump?
Start the pump by opening the flapper in the AFM or jumping the ports:
1634348697691.png
 
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You probably just got your wiring backwards. Get a multimeter out and check that you’ve got 12v to the hot wire when the Accessories are switched on.
 
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You probably just got your wiring backwards. Get a multimeter out and check that you’ve got 12v to the hot wire when the Accessories are switched on.

The thing is that I didn't remove or disconnect the fuel pump. I dropped the pan with the pump attached, which is doable with how the 40gal tank is shaped.

So something is not telling the pump to turn on, or the pump is dead right? I just can't find anything in the FSM that is talking about the fuel sending wires standing in the way of the fuel pump coming on.

Good to know I should have 12v going to the pump If the ACC is turned on, thank you.
 
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Maybe you missed a ground wire connection when hooking it all back up at the fuel pump?
Start the pump by opening the flapper in the AFM or jumping the ports:
View attachment 2813421
Thanks for this! I didn't know the role the Air flow meter played in turning on the fuel pump.
Do you know which connector it is referring to here in the top image? The one going to the air flow meter?
 
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I wonder if you pulled a wire loose when you dropped the tank. Are you using the factory pump? It should prime the lines with pressure when the ACC is switched on. If you have no fuel pressure and/or no 12v at the pump when ACC are toggled then figure out what got moved when you were working. If you do have 12v at the pump and no pressure then I’d say the pump is dead and it is coincidental that it happened while the tank was down.
 

red66toy

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Thanks for this! I didn't know the role the Air flow meter played in turning on the fuel pump.
Do you know which connector it is referring to here in the top image? The one going to the air flow meter?
The “check connector” is the pre-OBD ECU port on the engine bay firewall on the passenger side. I think @cps432 is onto something with a loose connection.
 
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Morning, so when I open the air flow flap a little, I hear a solonoid tick open, sounds like it's coming from the ECU area., and I get 12 v to the pump.

When I turn the key, I don't hear that one.
To little juice flowing through the IGN fuse or something?
Thanks guys
 
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Lots of incorrect information here about how the 62 fuel pump circuit works.

- The 62 Series fuel pump does NOT prime when the key is turned to ACC or ON.
- The fuel pump will NOT have power if the engine is not running, or the key is not being held in START.
- The fuel pump relay has a direct connection to the STA (start) wire. So if the key is held to START, the fuel pump relay (called the circuit opening relay) will turn on.
- The air flow meter has a circuit that will engage the circuit opening relay once it detects some air flow.

If you want to test the whole circuit, the simple thing to do is turn the key ON, take the air filter lid off, and then stick a long skinny object gently into the air flow meter to open the flap. You should hear a "click" as the circuit-opening relay turns on.

If you want to bypass the air flow meter and circuit opening relay for further testung, look at the CHECK connector located on the passenger side firewall. Put a jumper wire between the "B+" terminal and the "FP" terminal.
 
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Thanks @Lead Head
I just tried to start it with the air flow meter open. I hear the solonoid, tick open and close. But it won't start, does crank etc.
I'll try and video my volt meter attached to pump wires while cranking. If I do have voltage, think the pump is toast?
 
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...do you hear the fuel pump running? They're quite loud and it should be very evident if its running.

+12v at the pump doesn't mean anything. You still need a good, solid ground connection. So you will need to verify the fuel pump is actually grounded (you can do this by measure the voltage at the ground wire. It should be 0 volts or close to it when you have the fuel pump circuit energized). Additionally, that is still no indication of the wiring inside the tank.
 
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Lots of incorrect information here about how the 62 fuel pump circuit works.

- The 62 Series fuel pump does NOT prime when the key is turned to ACC or ON.
- The fuel pump will NOT have power if the engine is not running, or the key is not being held in START.
- The fuel pump relay has a direct connection to the STA (start) wire. So if the key is held to START, the fuel pump relay (called the circuit opening relay) will turn on.
- The air flow meter has a circuit that will engage the circuit opening relay once it detects some air flow.

If you want to test the whole circuit, the simple thing to do is turn the key ON, take the air filter lid off, and then stick a long skinny object gently into the air flow meter to open the flap. You should hear a "click" as the circuit-opening relay turns on.

If you want to bypass the air flow meter and circuit opening relay for further testung, look at the CHECK connector located on the passenger side firewall. Put a jumper wire between the "B+" terminal and the "FP" terminal.
Right, gotcha.
I do have 12 v at the wires inside the left cargo panel right now with the system energized.

How can I test the 0 volts on the ground? If I switch my multiple meter leads, I'm getting still 12v
 
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Right, gotcha.
I do have 12 v at the wires inside the left cargo panel right now with the system energized.

How can I test the 0 volts on the ground? If I switch my multiple meter leads, I'm getting still 12v
No sound from the pump.... I should be able to pull the pump assembly from underneath the cruiser with this tank.
 
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At the pump itself it's getting 12 v and I tried to hard ground it at the pump, no budge.
I'll take out the pump assembly.
I replaced the fuel pump filter sock and pump gasket a few months ago. Maybe I didn't put it back right.
It's been running perfectly though lately, doing lots of off roading and bumping around. Kinda weird a gentle tank removal would mess something up. I didn't even touch the pump assembly, only replaced the sending unit.
 
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Right, gotcha.
I do have 12 v at the wires inside the left cargo panel right now with the system energized.

How can I test the 0 volts on the ground? If I switch my multiple meter leads, I'm getting still 12v
You put one multimeter lead on the ground wire of the pump, and then another multimeter lead to a known good chassis or body ground. If you measure any voltage, it means the pump's ground wire is "floating" - i.e. not connected to ground.
 
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Lots of incorrect information here about how the 62 fuel pump circuit works.

- The 62 Series fuel pump does NOT prime when the key is turned to ACC or ON.
- The fuel pump will NOT have power if the engine is not running, or the key is not being held in START.
- The fuel pump relay has a direct connection to the STA (start) wire. So if the key is held to START, the fuel pump relay (called the circuit opening relay) will turn on.
- The air flow meter has a circuit that will engage the circuit opening relay once it detects some air flow.

If you want to test the whole circuit, the simple thing to do is turn the key ON, take the air filter lid off, and then stick a long skinny object gently into the air flow meter to open the flap. You should hear a "click" as the circuit-opening relay turns on.

If you want to bypass the air flow meter and circuit opening relay for further testung, look at the CHECK connector located on the passenger side firewall. Put a jumper wire between the "B+" terminal and the "FP" terminal.
Thank you for correcting the record. I guess the 62 works differently than I assumed.
 

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