chad711

I bought this truck a few weeks ago, it wasnt running great all the time when I picked it up. It would start just fine, run for maybe 3-4 minutes, then suddenly really start missing, to the point that it would die if you didnt hold it to the floor. Then after maybe a minute of that, it would suddenly run perfect. Took it out on a couple long drives, it was fine.

Anyways, today I fired it up, started to head to town and it died. Wouldnt start, checked the fuses under the hood (passenger fender towards firewall) the 15 amp fuse in the corner towards the firewall, right side, was blown. I replaced it, it ran for a few seconds and blew again. No cover on that fuseblock, so I dont know what that fuse is for other than it obviously is important.

I am new to the Toyotas so I dont have any exp on them, but Im thinking (hoping) someone here might be able to make a stab at whats going on here.

Thanks !

toyotaman2000

Did your truck come with an owners manual? I'm looking in mine (page 209 in mine) I have a 94. The only fuse that i see in the box that is 15 amp that would appear to be of major importance, which might make the engine die is fuse number 1 which is EFI Multi-port Fuel injection system/sequential multi-port fuel injection system.

I will look on mine in person tomorrow, if you have no cover on that fuse block i would say you should get one asap, when it rains water will go right in there.

If you have any further information on this let us know.

chad711

No manual, ordering a chiltons today if I cant find one in town.

toyotaman2000

I just looked on mine, the fuse that is blowing on you (i think) is what i said it was EFI Number 1. Here is a link to a 93 factory service manual

http://personal.utulsa.edu/~nathan-buchanan/93fsm/

Maybe browse it and save the link, it may help you fix your problem.

Keep us posted with any more information or when you fix this. I've never had this particular problem you are describing but it's probably something simple, it usually is.

toyotaman2000

also check out these attachments, save them on your computer.

Hope this helps. Again; if you can keep me posted on what you find out.





Ignore the red arrow in the diagram lol.

chad711

So it appears it is the EFI box shorting out ? Is that the box inside the cab on the passenger side near where your feet will be, right side ? I hear aklot of relay clicking from it at times.

Ironically I need that 80 amp fuse you have a red arrow to, it was blown when the kid I biought it from hooked the battery up backwords. I have it jumpered at the moment.

toyotaman2000

Having that 80 AMP fuse jumped could be your problem. Check out the FSM it probably has information for this topic.

chad711

Is that fuse hard to find, could a local NAPA order these ? Just curious why jumping that fuse would cause an issue? Also what does FSM stand for, thanks for the help.

mschein1

Factory Service Manual

toyotaman2000

FSM=Factory service manual I posted you a link above

Well I don't know that jumping that is the issue, though it could be. When messing with wiring you want to take your time, do your research and don't get into a hurry. There are wiring diagrams in the Factory service manual. It's easy to get into a hurry when we have a problem, I know when i do, i want to fix it asap. In the past I've gotten in too big of a hurry and ended up causing more problems.. lol which is not good.

As far as that 80 Amp fuse, I'm not totally sure. If i had to take a guess i would say its a dealer only item and probably 80 to 100$ but this is just a guess. If i was you i would look in that manual i linked you and you might want to search this forum too for information on the topic.

For now I have to go, i have some things to do. But do you research somewhere in that manual should give you troubleshooting directions.

Keep me posted, i will be back later.

Remember nothing good is easy lol. I just don't have much experience dealing with the problem you are describing But that FSM should help. Its like the bible for that truck. Even though its a different year the wiring should be close to the same (not guaranteed)

chad711

Well today it wont even fire. Here alone so cant really easily check for spark, fuel, will tonight. Im not hearing any relays clicking on that ecu in the cab now, at all. Pretty spendy Im sure ?

Great timing on this as I left my new truck in North Dakota for the week, now Im truckless !

TNRabbit

Jumping an 80 amp fuse is asking for a major meltdown!!

If there was a problem with that fuse blowing & you've jumped it, it is most likely that the O2 sensor wires have melted on your exhaust & shorted out. REPLACE THE 80 AMP FUSE BEFORE YOU CATCH YOUR TRUCK ON FIRE!!!!

chad711

I found a fuse at a local yard, still wont fire. On the lookout for a new computer. I have no spark at all.

chad711

Correction I do have spark. Is the fuel pump in the tank on these, is there an easy spot to check for fuel pressure?

chad711

Nice call ! So far it seems that may have been the problem, its running again.

Blue_petersen77

Cheap fix. Had the same exact problem. Make sure the O2 sensor Wire isn't touching the exhaust under driverside door.

Bassinfool

I had the same issue on my old '92 3.0 a few years back. Once you re-connect the wires (put some heatshrink over them) and make sure it's held down away from the exhaust you should be good to go.

toyotaman2000

Nice keep us posted.

toyotaman2000

is the check engine light on by the way? Or was it at anytime?

runnermedic

yep, efi fuse is melting beacuse the o2 sensor wires are melted and shorting with the exhaust or another cable,fix the cables and wrap them with temp resistant material,also make sure the cables stay away from the exhaust pipe.