2000 Tacoma 2.7L 4x4 EFI fuse keeps blowing

Hello everyone Im having an issue with my 2000 2.7L tacoma that I can't seem to figure out. The truck was running just fine during the day it stopped running. Hoped in it after lunch and go to and start it up... Turn over fine cranks at normal speed but doesn't fire. I look under the hood in the close fuse box and the 20 amp EFI fuse was blown. I replaced the fuse with another 20 amp and it started right up and I was able to turn around and head towards the o'reilly. I only got down the road maybe a quarter mile and the truck completely looses power and the motor dies. Since that event I have unplugged every component that leads to the EFI circuit that relates to this 20 amp EFI fuse but it continues to blow everytime I cycle the key. At this point I am assuming it is a wire to wire short somewhere in the wire harness but that is supposedly extremely rare and honestly doesn't make much sense to me because if it was shorted to another wire more than one fuse would be blowing but only one is. The only thing I can think of at this point is to replace the ECM but I don't wanna throw parts at it. Does anyone have a similar experience or any idea as to what the issue might be. Any help is much appreciated, thanks in advance.

 

The 20A fuse goes to the ECU and the EFI relay.
After the relay it goes to a few other places.

Id pull the EFI relay and see if the fuse still blows.
If it does, the problem is likely in the wiring to the ECU or maybe (unlikely) the ECU.

If the fuse does not blow, then it’s something after the relay.

Let us know what you find. Then we might be able to help you more.

 

I'm thinking it may be something that the ECU relay feeds from the fuse is shorted, O2 sensor heaters come to mind. I would give all the engine wiring a good look over for rubbed spots, chafing, or something melted to the exhaust or EGR tube, pay special attention to the wiring going to the O2 sensors.

 

Thank you guys for responding so quickly I really appreciate it. I looked everywhere I could physically see for wear marks and everything looked pretty good. Nothing touching the exhaust either. I couldn't see a single burn or chaff in the wire loom. I unplugged both o2 sensors along with fuel pump and 4 other sensors that are controlled by that fuse. I'm going to try what TnShooter said and unplug the relay tomorrow and see if it still blows. Thanks again to you both! I'll report back tomorrow with my findings.

 

It feeds alot of stuff on the engine, if you could find the junction connector 3E you could at least maybe isolate which branch of the circuit the short is on.

 

Do you have the wiring diagram for a 3rz?

 

Yes srry, I was reading your title.

 

I was a bit confused as well.
But the diagrams were close enough for the advice I gave.

The title says 2.4 and the main post says 2.7

Let us know how it goes OP.

 

Sorry about that! Totally my fault it's a 2.7 changing it now. I will let you guys know what happens thanks again

 

Hey guys!! Sorry it took me so long to jump back on here. Turn out the problem was 100% a short to ground! It took me awhile to find it but it was in the engine bay behind the motor. The efi wire was grounding out to the back of the valve cover where in passes between the fire wall and the motor. There is a bracket that is held by a bolt that holds the wiring harness away from the motor. The previous owner of the truck apparently didn't reattach that bracket and over time the wire finally got a pinhole in it which caused the short. Super hard to find because it was an intermittent issue and at certain points it would even run and then die. Thanks for all your help I appreciate it!

 

Thanks for the update.
Good to see you for it figured out

 

Yes same here, haha! Definitely kicked my butt. I know the truck up and down now, so that is a definite plus thanks again