"Re-set EFI Relay": Does it work?

[BamaDrewski]

I have read through a couple of posts all over the internet and it says to pull the EFI relay under the hood for 30 minutes and then re-install it for better gas mileage. (Engine off - battery connected). In my 2000 LTD 4WD, the "EFI Relay" is a baby blue colored, smaller relay under the hood in the fuse box. (It was not one of the big black relays) For me, I had no idea if this would work but figured I would try it. I did it last night and it does seem like I am getting better mileage but one of the posts said to run a full tank to make sure.

Has anyone else done this (or heard of this) and if so, did you see results? I appreciate any insight anyone has. On the other hand, if this is just hogwash, I would appreciate insight on that as well.

 

[tinman]

Interesting...I have heard of resetting the EFI relay also, but never done it. I may have to give it a try, just to see.

 

[BrianSD_42]

I have read through a couple of posts all over the internet and it says to pull the EFI relay under the hood for 30 minutes and then re-install it for better gas mileage.

If you are pulling it "just to get better gas mileage" then you are incorrect.

All pulling it will do is reset the EFI which if I understand it correctly uses a sensing algorithm to adjust the Fuel/Air mix which can sort of effect gas mileage.

Imagine this scenario: you take your 100% stock 4Runner and then you add a K&N CAI, Headers and high flow exhaust muffler.

That would be a good time to pull the fuse.

If you did not change any parts on your truck then don't pull the fuse because it will make no difference.

BTW - even if you did make the upgrades I mentioned but never pulled the fuse it won't matter that much because after a few days of driving the old EFI data times out anyways and the algorithm adjusts to the new airflow. People pull the fuse because the want to see the results right away and not a week later.

Personally, I have all those upgrades and I've never pulled the fuse. I didn't even know about it. I was just told by my mechanic that basically it may take a few days for the computer to fully adjust.

That is my understanding. Feel free to correct me if I'm wrong guys.

:hippie:

 

[LittleCaesar]

I would say it works about as well as this:
Tornado Air

Like Brian I have never pulled an EFI fuse for an upgrade and have had zero problems.

 

[sterbenlicht]

They're totally right. In fact, at first you'll probably notice it running a tiny bit worse because it's running on default values rather than the most appropriate ones for you. It'll take it a little bit of driving to learn it and run nice and smooth again.

Now, if you literally just bought your truck, then it has appropriate values that respond most suitably for whoever owned it or drove it regularly. It's only a slight change, but the fuel mapping will adjust on its own to whoever drives it. If you buy the truck from someone else, then you can immediately have it forget the old values and learn new ones for you over the course of about a tank of gas.

I'd actually disconnect the battery and let the vehicle cool down completely, then start it and let it idle all the way up to operating temperature so it can learn to idle properly by itself. Then drive it around for a while. If you've never cleaned your throttle body of carbon build up, and you do that right now, you'll see exactly why this reset can come in handy. Cleaning it and then running the truck, you'll notice it idling very high, and it'll take a few days for it to get back into the swing of things correctly.