Efi
 

As some of you know I had a post about no fire in my 93 toy 4runner, got that fixed, fired it up and was on my way, not, about a mile from the house it stopped again, just went dead...;. checked the fuses and found the EFI fuse was burnt, replaced it, fired it back up and headed home. About 2 blocks from the house it stopped again and again it was the EFI fuse, pulled a 10 amp from the flashers and made it home. Looking through my supply of fuses and found that I did not have any more 15 amp, so I did what you are not supposed to do replaced it with a 25 amp, took it out and ran it, no problem . Now the question is, why is the EFI pulling that many amps that it blows 15 amp fuses but a 25 will hold. When I hooked up the battery I watched for any sparks on the ground side, nothing so that should indicate no shorts, I am watching for something to go up in smoke,with the 25 amp and that will tell me where the problem is. For a vehicle that I wanted for an off road, back country ride, I don't trust it.

Check and clean all groundings including ECU grounding. Add a couple new ones. Check the crimpings in the injector harness Then try another correct fuse.

Is it possible there are other after market loads hooked into the EFI fuse circuit??

A short would cause the fuse to open I forget you have been doing this for years

Corrosion on the relay pins and sockets ?? causing more then the 15 amp draw

I figured it was a ground problem and then after looking at it, there were no grounds from the battery to the block and as far as I could see, and there were no provisions for one. I had made up a ground strap for my chevy that I didn't use and it fit the Toyota just right. Now it may be my imagination, but it seems to run better after I installed the ground strap, going from the neg side of the battery to the block. I haven't changed the fuse yet but will today, it got dark on me and the work had to stop. I did get all the dash parts reinstalled, some were cracked or broken and a hot glue gun got it back together.

Wyoming9 I checked the relay pins and sockets, they were looking good. No corrosion that I could see. There are no after market loads on the system so that can't be it. I am installing a CB, but that will go direct to the battery. I will try to go to town again today, but with a hand full of fuses, if it doesn't blow a fuse in 10 miles it probably will be ok, just don't trust it anymore.

Funny I had people tell me the same thing after installing the ground cables I made for them.

The only real new part is the fuel pump to high of in rush current for some reason??

Did you go with a Denso pump ??

Yes the new pump is a Denso, also a new coil and a new Fusible link in the fuse box.

Yes, the new pump is a Denso, I also replaced the coil and a fusable link in the fuse box.

Well that wasn't it, got about 1 1/2 miles from the house and it quit. I burned 6 fuses to get it back home, and thats the part I don't understand. If it was a short, the fuses would burn as soon as I turned the key on, but I can drive about 100 -200 yds. before they do. So something is pulling more amps then it should and it takes a while. The 15 amps went as soon as I turned the key, the 25 amp took a little longer and the 30 amp stayed the longest all to be expected, the heaver the amp the longer it took to blow. Now I need to find out what all the EFI controls.

OK, I checked the relay and it was working as it should. I then drilled out the ground wire on the fuel pump mount, cleaned it up with sand paper and used a rivet to reattach, placed a new fuse in the holder and fired it up. It sat and ran for about 1/2 hour running great, I then increased the motor speed until the RPM's were about the same as driving at 65 mpg and the fuse popped. So I think its somewhere in the air flow meter or something related to RPM's. Would the RPM's effect the ECU ???

Long shot but is it possible the movement of the engine is pinching a wire ??

Wire caught under the throttle pedal

We know it is not a dead short because the fuse does not open at once .

I wish I still lived in the Jackson area a road trip would be in order !!

I am curious to know how this plays out.

Best of Luck

My problem is I am not sure just what is connected to the EFI, is it possible that engine RPM's could effect the EFI through the air flow meter.I tested the air flow meter and it tested good. I was thinking last night, each time it shut down I was just getting up to hwy speed and it shut down in same place. so what is the connection between speed ( RPM'S ) and the EFI, wish I knew. I was going through some old posts and someone said it could be the CO2 wire, why would that shut the motor down. If it doesn't rain I will play with it again today and look at the co2 wire.

I did a test on the air flow meter and it checks out Vs--E2 should be 200 -600 mine read 287,,,VC --E2 200 to 400, mine reads 280, THA--E2 should be 0.9 ---1.3 here I am high 1.65.....On the airflow meter all the contacts points are there, on the plug end there is no E2 just a blank space, I took it apart to see if it just slipped out of the socket but there was no wire for that spot. I checked the CO2 wire and it is not involved with the exhaust pipe in any way. Getting back to the air flow meter, how level does it need to be, mine sits a little low in front, not much, but a little. You would think if any of these components it would just not run, but it does, just not for long, so far today I have blown 3 fuses, a 10 a 15 and a 30. the only thing I can think of is, as the motor get warm-hot something is expanding and grounding out causing a short. This morning I watched one of the fuses burn out, the right hand side is where the spark came from if you were standing next to the fender on the passenger side. Would that indicate that the short is in front of the fuse or thats just wishful thinking on my part. My next check will be to remove the fuse box and make sure that nothing is in contact with any of the wires underneath. I did have that box off.........

I think I found it, following wyoming9 'old post 5-7-16 he said the check the CO2 censer, I checked the wires and they looked great and far enough from the exhaust pipe not to be a problem......I then looked at the CO2 censer itself and some how while installing the headers I placed the wires coming out of the top of the censer very close to the frame, over time it moved up and when the pipe heated up it caused the wire to touch the frame and over time it rubbed the insulation off the wire, heat expands, the censer touched the frame and popped the fuse. Something so simple............

Lets hope that was all it was simple but took some time to trouble shoot

I learned more about Toyota's then I wanted to. I drove the Toyota over 50 miles today and it is fine, I was up in the mountains and ran it through the gears / 4 wheel drive, high and low/ all seemed to work ok. I did notice that when you get it up to about 4500 to 5000 rpm it starts missing. Opened the hood and touched the coil wire, should not have done that, about knocked me on my butt. I think new plug wires are in order.

Couple quick things..
 

Popping the efi fuse is almost always the oxygen sensor.

A high resistance ground reduces current flow, less resistance more current, no resistance infinite current.

The big wire of the battery negative is supposed to be attached to the block, the secondary/smaller wire goes to the fender as the body ground.

grousehunter 61
Well for what its worth, it quit again, drove it all day, had it up in the mountains went through all the gears, drove it home, parked it in the driveway and the next day went out to start it again and no go, turns over but no fire. I haven't even looked at it and right now don't care if I never do...........

I ran the codes and counted 52 ( I think ) it shows the knock sensor has an open circuit. ??? Is there a way to be certain that is what it is, It looks like a full day or more to get to the knock sensor.

The knock sensor (KS) isn't that bad to get to, I'm kind of a large guy, so I jack up the passenger front, and pull the tire. There's any inspection plate that you can unbolt, and the knock sensor is right there in the side of the block. I was having issues with my KS, so I pulled it cleaned up all the threads, reinstalled and it hasn't come back since.

Think he's running a 3vz truck. Not so easy then.