bsamsyota

First off, I want to say thank you to everyone who puts their input in on this site. I have fixed many problems just searching this site as a visitor. I have one problem now that I still can't figure out, I realize that I am long winded, but I want to give a "big picture" view of what I got myself into. I recently traded my 1/2 ton GMC for a 91 Toyota Pickup 4x4 with a 22r engine and some cash. Well the cash is almost all used up and I need to figure out my problem. The head was recently rebuilt along with a new timing chain and guides by the guy I got the truck from. He's a good mechanic and knows his stuff, he just didn't take good care of this truck. I drove the truck home (about 60 miles) it ran at speed ok but would not idle, took it out a few days later, got 30 miles from home and it quit running. It popped the 30 amp fuse (on the cover it is listed as AM2), I replaced it and the fuse popped immediately. I checked the wires to the to the pump and they are fine, so I replaced the pump. The truck has never been taken care of very well and is very rusty underneath. I busted two holes in the fuel lines on the bracket that holds the fuel pump. I replaced the entire bracket at the same time I replaced the pump. I then replaced the fuse, drove it 3 miles and the fuse popped. I trailered the truck home and installed a 30 amp breaker so I wouldn't have to buy anymore fuses. I found a ground wire that went to the starter that was almost completely rubbed thru, I repaired it and the truck runs good, but idles rough. Took it for a drive, it went for an hour and then popped the fuse. Once the truck cools down it will run for a while just fine. The fuel filter looked old, so I replaced it thinking that it is clogged and overheating the pump. (I should have done this when I changed pumps...lesson learned) It was definitely filthy, the idle problem is fixed, but it still dies after running for 30 to 45 minutes. Unfortunately it has to be driven for it to die, It will idle all day long if you want it too. The fuel pump relay is new too. All new ground wires on the battery along with new terminals. The relay feels hot to me when I check it right after the fuse pops (I'm not a mechanic though).

My question is where do I start from here?

Are there any cheap fixes?

Why isn't the 15 amp EFI fuse popping?

Could that clogged fuel filter have ruined my new pump in just one hour?

Any help would be great, I will be working on it all day today. Need to get this fixed so I can go chase turkeys all weekend.

Thanks,
Brett

jessed59

my buddys 3.0 was poppin one of those bigger fuses... it turned out to be a wire that was shorting out due to an oil leak. he pulled that wire an cleaned it off an he quit fryin fuses... i wasnt there for it so i couldnt explain which wire but its a 3.0 also so basically check/wipe down any oily wires in the engine compartment also if its a paired wire be sure to check if insulation between the 2 wires is still there its obviously shorting out but the question is where make sure no wires are touching hot parts exhaust manifold/block etc wish i had more to offer hopefully this helps ill look at my bros 22r an try an route that fuse ill post info if i find anything

bsamsyota

Awesome info, thanks!! I got the bed off, the seat out and the carpet up looking for any burnt wires. Just started under to hood, haven't found any yet. I will start cleaning them all off. Thanks again!!

Team420

Here are a couple linkx to the schematics for a 93 4runner... they should apply to your 91 p/u as well, although the wires may be a different color than shown...

Engine control...
http://ncttora.com/fsm/1990-1995_4Rn...emci/eng2r.pdf

Pwer Source a
http://ncttora.com/fsm/1990-1995_4Rn...u/powersou.pdf

power source b
http://ncttora.com/fsm/1990-1995_4Rn...i/pwrsourc.pdf

Full FSM
http://ncttora.com/fsm/1990-1995_4Rn...5/contents.htm

Hope you're handy with a multimeter! Good Luck!

jessed59

ya no prob also read up a little sounds like it will be wiring with your ignition system.. so check all that out good luck

bsamsyota

Thanks for all your help fellas. I will update if I find anything.

peckinpah

I pooped that fuse while messing the "cigarette lighter" or "accessory plug" or whatever you call it. Plugged in a bluetooth speaker phone device and it shorted, sparked and actually caught on fire. After that, the truck would not start and it turned out to be the 30 amp fuse was blown.

bsamsyota

Still having trouble identifying the culprit. There isn't a dirty wire on the truck now, I can't seem to find any wires that are corroded or broke that would be shorting out. It still idles rough and dies after it has been running a while. If I go highway speeds and begin to slow down for a off ramp that fuse will pop. I'm not very good using a multi-meter, I have started to read up on that so I can use that tool to help me. I even unhooked the accessory plug!! Thanks for the help so far, if you know of any sites that have a cheat sheet for using a multi-meter that would be helpful too.

Also, we checked it with a friends meter and a I was getting 9.7 volts to that fuse with the truck key off and 12 volts when the key was in the on position. Not Normal... right???