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Every time I turn the key to the on position I blow the EFI fuse. I'm at a total loss on this thing. First time it did this I was about 3 miles down a trail at the bottom of a hill and took 6 hours to drag it back to the road. I've searched and searched all over the internet and the only thing I could come up with was either bad fuel pump or bad circuit opening relay. Here's what I've done so far:

-followed all wires looking for pinch points or shorts
-swapped the 2 large relays under hood
-checked ground wires

This is where it gets confusing:

-I unplugged the fuel pump harness from the tank and then turned the key. EFI fuse did NOT blow. So I thought "must be a bad pump". Then I plug the harness back in to see if it would blow the fuse again. Truck fired up and ran. Drove it about a mile and it blew the fuse and cut off. Pulled it home.

-Unplugged the Circuit Opening Relay from under the dash. After I pulled it out I turned the key. Truck did NOT blow a fuse. Plugged it back in and it DID blow fuse. Then I took the relay and banged it on the toolbox a few times and plugged it back in. Truck fired up and ran. Then I though "must be the relay then"

WRONG. Now it's blowing the EFI fuse as soon as I turn the key even with the circuit opening relay AND the fuel pump unplugged. I'm at a total loss on this. I guess they are saying a "big" snow storm is headed our way and I'd like to make another attempt to fix it so I can take it out.


If anyone has any suggestions as to something I could try I'd really appreciate it.

Thanks
 

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It sounds like you may have a chaffed wire in the power lead to the fuel pump. It goes under the truck from inside the cab through a grommet under the drivers seat. Pull the seat and trace the wire all the way back to the pump and forward inside to the relay.
Connect a beeper between the power lead and ground then start wiggling. You'll likely have to disconnect the fuel pump so the low resistance of the pump doesn't activate the beeper.


[QUO=CalypsoNotch;2650113]Every time I turn the key to the on position I blow the EFI fuse. I'm at a total loss on this thing. First time it did this I was about 3 miles down a trail at the bottom of a hill and took 6 hours to drag it back to the road. I've searched and searched all over the internet and the only thing I could come up with was either bad fuel pump or bad circuit opening relay. Here's what I've done so far:

-followed all wires looking for pinch points or shorts
-swapped the 2 large relays under hood
-checked ground wires

This is where it gets confusing:

-I unplugged the fuel pump harness from the tank and then turned the key. EFI fuse did NOT blow. So I thought "must be a bad pump". Then I plug the harness back in to see if it would blow the fuse again. Truck fired up and ran. Drove it about a mile and it blew the fuse and cut off. Pulled it home.

-Unplugged the Circuit Opening Relay from under the dash. After I pulled it out I turned the key. Truck did NOT blow a fuse. Plugged it back in and it DID blow fuse. Then I took the relay and banged it on the toolbox a few times and plugged it back in. Truck fired up and ran. Then I though "must be the relay then"

WRONG. Now it's blowing the EFI fuse as soon as I turn the key even with the circuit opening relay AND the fuel pump unplugged. I'm at a total loss on this. I guess they are saying a "big" snow storm is headed our way and I'd like to make another attempt to fix it so I can take it out.


If anyone has any suggestions as to something I could try I'd really appreciate it.

Thanks[/QUOTE]
 

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EFI Fuse

Check your O2 sensor, they have a tendency to short against the exhaust and blow the that fuse. I'm assuming your truck in new enough to have the 4 wire O2 sensor, not the old one wire.

And how about that, Dick is still alive!:surprise:
 

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Check your O2 sensor, they have a tendency to short against the exhaust and blow the that fuse. I'm assuming your truck in new enough to have the 4 wire O2 sensor, not the old one wire.

And how about that, Dick is still alive!:surprise:
That could be the culprit. BTW I don't think Toyota has ever used one wire O2 sensor. Most have had at least four wires. Two for heater and two for the sensor itself. Of course a shorted ground isn't going to blow a fuse but the other two will but most likely the heater hot wire.
 
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