98 tacoma fuel pump relay problem

Buddy has a 98 tacoma 4 cylinder that sat in his backyard for about 3 years.. Tried to crank it and it would turn over and want too crank but wouldnt.. first thing in mind is the fuel pump from bad gas.. Put my ear to the gas cap didnt hear pump turn on.. unscrewed fuel line from motor and tried cranking truck and no gas squirted out.. no pressure.. so I dropped the tank and unplugged the harness to the pump, stuck a meter to it and no power going to it so i checked the efi relay under the hood and relay was good with power going to it.. somebody mentioned another relay under the steering wheel, took the dash off and found it. checked it with meter and relay was good but had no power going to it.. Is there a open fuse relay somewhere else that could be bad? somebody told me under the glove box but I could not find one.. oh and the o2 sensor has been chewed off by dog if that has anything to do with my problem.. any help?

 

If you suspect the EFI relay, swap it with the accessory power relay. They are the same. Make sure the accessory power is working first.

 

I swapped them around and nothing... maybe ecm is bad? Im thinking their is a short between the relay and pump cause the relay has power but no power at the pump..

 

Wiring problem? Perhaps a rodent chewed thru the wiring harness between the pump and the relay.

 

Remember when testing a relay, you will have TWO sources of power. One is for control of the the relay, the other is the power the relay is operating.

On the 1998 Tacoma with a 2.7 (you didnt specify which 4 cylinder you have) it shows that on the Circuit opening Relay (in the dash area) terminal #2 is the "hot" wire used to power the fuel pump, and terminal 3 is the power from the "STA" fuse that is used to energize the relay. Check for power on BOTH of those terminals with the key on. Terminal 4 should have a ground present for 2-3 seconds when key turned on, as well as during cranking as this is the ECU energizing the fuel pump circuit of the Opening Relay.
If there is no power at terminal 2 of the Opening Relay, look at your EFI relay. Terminal 3 and terminal 1 should have power with key on. also terminal 2 should have a ground. If terminal 1 does not have power, inspect the "IGN FUSE", if terminal 3 has no power, inspect the "EFI FUSE"

 

I went to a junk yard and got another computer for it and swapped it out.. started right up! I dont know if its where it sat for years and it just went bad or something..(sounds weird) but it worked!! thanks for all the help tho!