darkwaterdiver

I am at a loss on what to look for next on a problem that I having with my 92 4runner (3.0). The problem started with intermittent sputtering and back firing and progressed to a no start issue. Im a noob with Toyotas, but using the wonderful search feature here on yotatech I came up with a few things to try. I started by checking all the fuses and testing the EFI and COR relays per the FSM. The fuses were all good but I replaced them anyways, and I did the test jump on the B+ and FP terminals in the diagnostic box. The fuel pump did not run on the jump, so I had our electrical department at work double check the relays before I bought a new fuel pump. I installed the fuel pump last night and still nothing. I broke out the multi meter today and started testing. The fuel pump was not getting power so I did the test jump again....still nothing. There was continuity between the b and fp, but I was not getting 12v at B+. I ran a jump from the FP terminal to the positive post on the battery and the fuel pump kicked on. I played around a little more and pulled the EFI relay to check volts there. I had 12v at the 5 pin, so I decided to run a jump between the 5 & 3 to see what would happen......the truck fired right up for the first time in two weeks. I had the EFI relay checked yet again, and I also bought a new one. The truck wont run with either relay; it will only run with the 5, 3 jump wire in place of the EFI relay. Im not very good with chasing down wires, so I thought I would ask if anyone might have some advice that they could offer on what to try next.

MudHippy

It seems as though you've missed one small detail. That being the IGN fuse and its connection to the EFI main relay. If the IGN fuse is blown, the EFI main relay can't close the 5-3 circuit when the ignition switch closes the IG2 circuit. If the IGN fuse is not blown, then the problem is in:

a. the wiring from the IG2 circuit to the IGN fuse
b. the wiring from the IGN fuse to the EFI main relay #1 pin
c. the wiring from the EFI main relay #2 pin to ground(body)
d. all, or any combination, of the above

darkwaterdiver

Thank you very much for the response. I did check the IGN fuse, and I did replace it even though it appeared fine. Ill start checking the wiring that you suggested this evening or weekend. One thing that I was curious about was the B+ terminal in the diagnostic box not showing 12v when I checked it. Shouldn't that terminal have 12v or would what you mentioned above affect that diagnostic box too? One other tidbit of info that I forgot to mention was that the CEL process from the diagnostic box did not work for me either. The CEL does not flash at all.

scope103

Just to state the obvious, all these tests are "Key-On, Engine-Off." There is no 12v on the B+ terminal with the key off, as the EFI relay is open with Key-Off. When you turn the key to on, the CEL (MIL) should come on solid. Since you don't have 12v on B+, lack of CEL is not surprising.

As MudHippy made clear, the first thing to do is pull the EFI relay, and check for 12v on 1-2 with the key-on. It sounds like you won't get it, but you'll be on your way to finding the problem.

darkwaterdiver

You're right, I don't have 12v on 1-2 with the key on. I really appreciate the responses y'all; Ill get to doing what y'all said and see where that takes me. Thanks again.

Innocent Fool

Might also want to check the harness connector under the passenger seat for corrosion or damage. This connector feeds the Fuel Pump motor and things like fuel gauge, tail lights etc.... I had a runner that would sometimes crap out and it was the connector .