This is probly not the correct forum, but I am working on a '99 3.4L 4runner. Please forgibs. copy from 3.4 swap forum. (many less eyeballs)

In the process of checking my wiring and as many circuits as I can think of, I also was checking my fuel pump (back in APril. Went sailing for few weeks and been back at it now for couple of weeks.)
1999 3.4 MT into a 95 4runner. Adding that still using th 2nd gen COR relay and harness. Which works. But bought a second unit because I'm stumped. Even works properly with a 9v battery.

in '20 while still working I did wiring on my week off inbetween rotations. Typically would think I got it (write down the important parts), come back couple of weeks later and do it again. Then compare, with reference to dntsdad and the Monch's write ups mostly. Then did my actual harnesses probably few months later by that time.

So here is my issue. I started by checking my TopSecret Kill Switch (basically just interrupts the pwr to the pump, after all the COR goodness). Fail. double check all that before I get the carpet and seats back in. Pwr direct to 'downhill' side of switch works fine. So I made a test light and put in place where my switch is, but still nada. So over the past cpl weeks been looking/searching for swap threads to see what others have done.
And continue to test. So after all the trials and testing (did find 35 ohms in my clutch safety switch. So at this point I have basically just jumpered around it so 'clutch is permanently depressed'. Reading Monch's thread and jumping around my COR relay I was pretty sure I failed to connect the COR pin 4 (on original 3vz wire harness) to the FC pin E14-3 (IIRC) on the 99 ecu.

If you've stuck with me so far, this is the crux. Checked all three sheets I had, and even wrote "DONE" on the pinout sheet. But as I'm always a DA, finally decided yesterday to pull evap and blower unit out, split my loom back open and follow the G/Y wire. It seemed good. Ended up bustin open my IH-1 connector, plugged in dummy bypasses and try again. Nada. Check with the ol meter. Sho nuff, I do have 12V (actually 10 some cuz battery is week unless I put charger on it.). However there is ZERO continutiy to ground on pin 3. Even pulled plug out of ECM, cut/made a pin from the old 94's ECU pin to fit INTO the E14 plug. Have continuity all the way back to EFI relay. So try again, and when I use my little bypass and touch to the frame - bingo. My test bulb monstrosity comes on.

Q: This (the connection of the FC signal - which is actually just 12V from the Switched Power side of EFI relay) activates COR closing pins 1 and 2 (pwr for physical pump). If I supply ground rather than dependind on the ECM to ground that circuit, it works. Can anyone think what I might be missing? I prayed for two days that I was just a dumba and forgot the g/y. Not so. I'm beginning to fear my ECM will not (for whatever reason) pull that pin to gound.

I did NOT connect the MREL (on the 99 that just provides coil power for the EFI relay). Didn't think its needed. I aslo need to double check (haven't got to it yet) the STA circuit. Think I'll redo dash harness wire and move the 'clutch safety' stuff 'upstream' of the Start Relay, so Start relay coil power goes to STA (e14-7). In fact I may not have that correct either. Altho the 99 EWD description refers to it as a Source in one location, and an input signal (in the Starter Circuit section) otherwise. Seems good way to roast some TTL crap.

Can't believe I'm having all this trouble, because literally no one else ever seemed to struggle with this issue. But don't trust my thinking anymore either. Caught myself multiple times using Black as a ground (vs White or some combo as Toyota typically does). Big Evil Red Oil Services company always did stuff different.

Any words of wisdom greatly appreciated.

 

Oooff. If any home gamers are still looking for answers, my problem might be presence of Anti-theft system wiring.
Now trying to figure out IF the donor vehicle had it. And if so, how to plumb around.

 

updates in the 3,4 Swap forum.

No. It's not pretty.