Donovan

DAMNIT! I really need to sell my truck soon. I'm getting a house and I don't need four cars.
The problem is the EFI fuse blowing in my '90. I've tried all kinds of things but it seems to not like something (me?) I cleaned all the negative terminals I could reach. I regrounded it with one new wire. I tried replacing the positive wire to the fuse block, new battery, and still bam! I got about 100 feet and the fuse went out again.
I'm at a loss now. Anyone solve this problem with something other then the usual reasons?

nunsa

A usual problem would be the wrong amperage fuse. Other problems would be a bad ground or voltage is back feeding, or your ground is "hot" ! If you really want to unload it, just put a high amp fuse in it or replace the fuse with a piece of wire.

Donovan

Whoa I don't want it to burst into flames once it rolls off the parking lot. I have a 20 amper in there now but it pops that too. Do you think it'd burn something up if I put say a 30 or something in there? I know it wouldn't be "good" but would it work?

4Crawler

iTrader: (3)

Check the wires at the O2 sensor(s). Not uncommon for them to make contact with the (hot) exhaust tubing and that melts the insulation and poof goes the EFI fuse.

DarylD

I saw this happen before . We found the ground wire at the fuel pump had worked loose causing the fuse to blow .

Bassinfool

I just fixed that problem. Wires were all chewed up. Get butt joints & heat shrink tube & re-wire it if that's the case. Then get a bracket to hold the wires up & away from the exhaust. Haven't had that problem since.

MTL_4runner

If you are popping a 20 amp fuse DO NOT hard wire it as was suggested.
I would check the fuel pump and O2 wiring as was suggested to find the actual cause of the problem.

Bassinfool

**Quick Check**
Jump your TE1 & E1 terminals under the hood. If you get a code 21, it's probably the wires to your O2 sensor melted. If no code 21, find the C9 wire connection under passenger side dash (right behind front speaker). Check with your toyota service dept (I can't remember which ones) on which two terminals to put a fusible link to with a 10a fuse & turn the key to on. If you blow that fuse, it's your fuel pump.

Donovan

Thanks guys I was REALLY hopeing that it was not the fuel pump, however If all else fails I changed to a Supra TT fuel pump in my RX7 and it was really easy as it is accesable from the inside of the car. How much of a biotch is the FP in a 4Runner?

rah1420

Heh. A real bitch. It's in the freakin' tank.

My EFI fuse is blowing too. It's not the O2 sensor... at least I don't think so (the wires are well out of the way of the exhaust pipe.) I'm praying it's not the damn fuel pump.

rah1420

Where are these terminals? My Hayes manual is worthless. And is this a code you can read with a test lamp or LED, or is this an OBD reader-type code that I won't be able to read since I don't have a reader?

Damn, I'll bet that's it. No, I haven't tried it yet. Another problem is that I did have a bad ground; a bad ground connection at the neg battery terminal itself. I cleaned that up today, but who the hell knows what damage I did??

Donovan

thought I'd move this up here since no one was looking at the other thread?
I'm thinking about fuel pumps.... hmmmmm
Here's the deal. I've go t a '90 4Runner that may have a bad fuel pump. While looking for info on the net I read that the first get 4Runner had a hatch under the rear seats to get to the pump without droping the tank.I replaced the pump in my RX-7 and it was done the same way. I replaced it with a supra TT pump, the old one was still fine.
Now then on my '90 is there a door? If not then what about making one?? would it be possible to get some tin snips in there and make a hatch then cover it with some sheet metal or the like??? Would this be dangerous or even possible? I'm also wondering if the old RX7 fuel pump would be able to replace the Runner pump. The supra is a direct bolt in (same pickup and all) so I'm also wondering if the RX7's pump would be usable in this situation?????
Your thoughts

4Crawler

iTrader: (3)

Flip up the rear seat bottom and look, takes 10 seconds . As I recall, there is either no hatch or the hatch is too small to remove the pump on the 2nd gens, but I don't have one so I don't know for sure. There is on the 1st gens and the pump comes out very easy.

How have you determined the pump is bad? They are quite reliable. Unplug it and see if you can apply power to the connector directly.

Donovan

Um..... Oh yeah! Actually I just havn't done it yet, Plus I'd have to put my shoes on and go outside so it's more like 30-45 seconds I'm just trying to avoid dropping the tank as it is not really easy and I don't have a lot of time.
I'm going to look for the O2 grounding out and if that's not it I'm going to have to guess it's something with the fuel pump and/or it's wireing.

4Crawler

iTrader: (3)

Not that hard to drop the tank. 6 bolts hold the skid plate up, 6 more bolts hold the tank. There is a drain plug in the bottom of the tank, but if it is nearly empty, it is not that heavy. I've dropped mine several times, the first was a bit intimidating until I did it. I found trying to use jack stands and a fllor jack under there was a PITA, so now I just lay under the tank, unbolt it, drop it down and slide it to the ground.

Duffdog

another thing that could make the EFI fuse blow is the "EFI"!!!!!! bad fuel injectors can draw too much current and cause problems like that. A noid light could help in that situation.

T

Bassinfool

[QUOTE=rah1420]Where are these terminals? My Hayes manual is worthless. And is this a code you can read with a test lamp or LED, or is this an OBD reader-type code that I won't be able to read since I don't have a reader?


Check out this link. http://autorepair.about.com/library/...bl-dtcs-90.htm . You don't need a reader. Just jump a small wire between those two terminals. The code reads out by your check engine light blinking a "morse code" like count. Count the number of blinks, then a pause, then the number of blinks again. Check your Haynes manual, around page 6-35 or so for all the trouble codes.

4Crawler

iTrader: (3)

Get a Factory Service Manual:
http://www.4crawler.com/4x4/FSM.shtml

Diagnostic connector information:

http://www.4crawler.com/4x4/CheapTri...CheckConnector

And how to do perform and interpret the test:

http://www.off-road.com/toyota/tech/codes/index.html

SlimJim248@earthlink

If you opened up your afm, check the contacts in there. I hit the metal contacts in mine and they were touching eachother and that kept blowing my efi fuse.

rah1420

Well, I jumped the B+ and FP on the diagnostic port after I turn the ignition on; the fuel pump runs (for a few seconds) then I see the fuse blow. Sheeeit.

With all this damn snow on the ground, I guess I'll be towing it into the mechanic to work on it. I am not dropping a fuel tank with a foot of snow on the ground. (Well, it's less but it's still a PITA.)