Keep blowing 20 amp efi fuse.

My rav4 has intermittant short also . Gauge fuse . To make along story short I installed circuit breaker to replace fuse. They sell small circuit breakes that replace fuse . Only affects ac windows and cooling fan but doesnt die out . Mine resets after a few seconds and good for a long time .
Friend might want to install a circuit breaker in mean time.

 

This is my first post in a tacoma forum. I'm Timmy's buddy with the EFI fuse blowing.

I have 1996 Toyota 4runner Limited 3.4L In a nutshell, we went to Death Valley. Never had an issue with my rig before that. The theory is (just a theory) that a rodent found it's way into my rig that night. I do have one injector wire that has a small "naw" in it. It's taped up and I was told theres no way that wire could cause an arc big enough to blow the fuse.

The next day we were driving 35-40mph on tough washboard roads. Temp was 101 and out of the blue my car shut down. We never traced the problem (even with 7 mechanics out there lol). Long story short, I towed it home 624 miles.

A few weeks later, I took everything apart on the top of my engine to check all the connections. Everything looked fine. I go to start the car and it fires right up (and I'm thinking it's fixed now). I drove a few hundred miles then decided to make another trip to the Sierras. I made it the 150 plus mile trip no problem. The next (very hot day) I'm climbing a fairly decent hill (I'm still in the Sierras), doing about 30mph and my rig blows a fuse (totally bumming at this point). I let my rig sit for a few hours, came back, put a new fuse in and it started. I was able to drive it back home 150 miles with no issues.

I then had my personal mechanical look over my rig. He checked the O2 sensors and the top end of my car. He said everything looked great. About a month later (maybe Sept) also a warm/hot day, I decide to go the EEL/Mendocino area....its about 80 miles from my house (I was prepared for a 100 mile tow from AAA) .Sure as shit, I'm driving the curves and hills after 70 miles on the freeway and my EFI fuse blows again. Since September, I have probably driven it 20 times on a 60 mile round trip....30 miles each way. I haven't had the fuse blow since September. It sure seems to "heat" related.

This is seriously discouraging to me. I have three 90's Toyotas and I DO NOT want to get rid of my rig nor do I want to sell it. I love this rig and so badly want to find out what's going on.

I do have a FSM and an electrical wiring diagram but electrical is not my strong suit.

Timmy is right about the $200/hr....if anyone every is directly responsible for helping me figure out my issue (must be certain 100%) , I will happily PayPal that person $200. This feels like worse than a needle in haystack because no one can trace the problem if the fuse doesn't blow. So frustrating. I'm hoping some of you geniuses can figure this out.

 

It may be time to start throwing parts at it. I've done some research on this problem and there's a fair amount of posts about it on different sites but no conclusive culprit to look into. What I did read is that the fuel pump has the largest current draw on that EFI circuit. The fact that you don't get the problem all the time leads me to believe this is not a bare wire somewhere on the circuit grounding out. If it was, you'd think it would do it all the time and not just intermittently and on hot days. If it were me, I'd take the chance and drop the tank to replace the fuel pump. An OEM fuel pump isn't exactly cheap, around $220-$240, but if I was starting to consider selling the rig because of this problem, I'd take this chance that it fixes the problem.

 

If you believe it’s heat related, maybe start looking at the components connected to that EFI fuse. Could be that when it’s too hot that component would heat up and somehow cause a short or more current draw that trips the fuse. What Tim said about the fuel pump sounds plausible. However if you start to throw parts at it, the second or third time around it might cost the same as taking it to a Toyota dealership. Have you tried calling around the Toyota dealership in your area and see what they would charge for a diagnostic?

Might be not connected but have you connected a scan tool before and after the fuse is blown to see if it throws a code?

Also the wire that got chewed, have you thought about replacing that section of the wire instead of tapping it up? Have you looked around the area to make sure nothing else is chewed or no wire could come in contact?

From what you said, heat creates more current draw which blows the fuse. That and or heat creates a malfunction somewhere that is connected to the EFI fuse.

One more thing. If you have FB there’s group called 559yotas. There’s a lot of guys that have 4Runners on there and there’s at least one person on there that works at a Toyota dealership.

 

You might also be able to rig up an amp meter, I'd imagine. An added expense and complexity, but you might be able to narrow down where the amp spike is coming from.

 

And 06 4.0 to come out with a very similar problem. I have replaced the pump thinking it fixed it and then three months later it blows the fuse again. Been checking all the wires nothing yet. Thing is that the power lock relay flicker sometimes