WEIMAR

Hey guys, long time follower of YT but first time poster. I'm finishing up a 3.4 swap from a 98 4runner A/T to a 92 4runner A/T. Got it all finished up and went to go crank it up and noticed the fuel pump isn't kicking on at all. First thing I did was check my wiring at the COR, which I used the 98 4 wire COR, and found that the ECU G-Y FC wire isn't supplying the COR the necessary path to ground so the COR is sending 12v straight through the relay to the ECU pin FC looking for a ground and not letting my fuel pump kick on.

I have checked that this wire is connected correctly and that my fuel pump does work and that when I add a ground to the COR G-Y wire that the fuel pump does come on and stay on full time.

My question is more or less looking for advice on what I should be looking for or why would the ECU not provide this ground to activate the COR via FC? Is there some sort of enabling criteria for FC to provide a ground? is my ECM Bad? Anything you can give me would be greatly appreciated. Thank you.

WEIMAR

So no advice as expected, so I got into it further and decided this had to be a bad ECM. Unplugged it, cracked the case open on the ECM and found my issue. The ECM is bad, the green board was covered in rust and showed signs of arcing on the case itself. Since I needed the vehicle asap I decided to gently remove the rust from the case and green-board. I located all the damaged resistors from the corrosion and replaced them with some that matched from an old unused ECM I had already. Put it back together plugged it back in and retested my connections for FC, and it is now providing the necessary path to ground and providing fuel pump activation. I ordered a "new" ECM, mainly because I wasn't able to repair all damage to it but enough to get it started and confirm the ecm was bad. Problem solved.

calipatient

iTrader: (1)

sucks you got no response... but thx for the follow up!

vital22re

iTrader: (2)

Not everyone is gonna be able to respond within 2 days. But it's good you figured it out. Why did you choose to use the 3.4 cor? I've used the 3.0 in all the swaps I've done with no issue what's so ever.

A New High

I'm currently in the deciding process of which COR to use myself.

The 3.4 appears much simpler. 3 of the 4 3.0 COR wires run through IH1, yet II3 doesn't have a corresponding pin.

I'm trying to do as little splicing, and as much re-pinning as possible.

I wish more people had breakdowns of their wiring like Elvota. I've made a pretty helpful spreadsheet I'll post when I'm finished with my wiring.

ChefYota4x4

iTrader: (5)

Especially on the 4th Of July Weekend, ....day before. I noticed it's been slow. I too am glad you got it figured out man...nice work!

WEIMAR

Just was in a hurry and expected a bit quicker response from such a large group, just bad timing on the start of the 4th of July weekend.

I chose the 3.4 COR mainly because of what A New High said, it just appeared more simple and got rid of another unused wire.

As for more people sharing diagrams, it becomes pretty tough, and if you have yet to venture into the wiring you'll see. No matter how much experience you have usually everything starts very clean and organized and ends up being more of a wire by wire chase. Changes along the way of the "plan" makes it difficult to document, I plan on coming up with a bit of a detailed diagram for my particular swap for future repairs/testing and trying to document issues i ran into in my wiring. If it comes out I will be sure to share it with everyone via this thread. Thanks guys

ChefYota4x4

iTrader: (5)

That'll be great, Weimar! Lots of people REALLY wanting to do this swap, ...and I KNOW that's the most times taking difficult portion in the majority that I've read. The 1UZ swap has it's own drama, .... like making the AC fit, etc., lol.

A New High

Well, I decided to use the 92 COR and regret it. Now I have to figure out why it's not kicking my pump on ;/

dntsdad

It doesn't get any easier than using the 3.4 setup.

Ignition to two poles. FC to the opposite side of the coil on the relay. Output to the fuel pump.

WEIMAR

Completely agree, it was a simplified route to go but the 5 pole relay isn't much different so maybe we can help a new high find his issue if he hasn't already. What kind of readings are you getting with your DMM at each pole on your relay?

jasond

Take the green with yellow stripe wire on the original fuel pump relay in your 92 runner (pin 23 of connector IH1) to the "FC" terminal on the 5vz ecu (not real sure what 5vz ecu you are running)