FJ80 EFI Main Relay Overheating Problem (1 Viewer)

[Africacruiser]

Hi all,

This is my first time posting on this site. I looked through it but didn't find anything relating to my specific problem. I really hope ya'll can help me here as I have a Landcruiser stuck in the middle of Ethiopia right now and no one, or website, seems to have the answers to help me fix my problem.

I've got a 1991 3FE FJ80 LC we use for offroad archaeolgoical research. The problem occurs when the vehicle is run for an hour or more whereby the EFI main relay overheats and dies. The only solution to the problem we've found is to switch out the super hot relay with a cool one. This, of course, is only a temporary fix as the new relay overheats as well in time. Ultimately, we end up switching relays as quick as every 5 minutes...in the middle of nowhere. Not to reliable if you ask me.

I've gone through and checked the fuel pump and sending unit. It all seems to be fine. As far as I remember the wiring to the EFI relay is 12 guage and seems ok. I have not been back to Ethiopia with a volt meter to check for faulty grounds, etc.

Does anyone have any information on 1) what causes this problem, 2) how I can fix it, 3) recommended parts to replace that might fix the problem. What could be increasing the voltage to the EFI relay that could cause it to overheat like it does?

Thanks!

 

[landtank]

very common problem. Toyota undersized the wiring to that relay and that wiring needs to be upgraded. I'll go find the link and get back to you. Posting this much now incase you are still on.

 

[Africacruiser]

THANKS! I'll stay on for a while.

 

[landtank]

here you go


http://www.safari4x4.com.au/80scool/tech/efi_relay.html

I'd install a new relay along with the wiring change.

 

[Africacruiser]

Thanks for the link. Do you recommend replacing the entire wire harness or only the relay wiring to and from the fuel pump?

 

[CharlieS]

I don't know squat about the issue, but as I read Rick's link to the 80scool board, it appears the important info is this:

"After much research, I have found the solution to the 3F EFI relay problem. Replace 12 gauge wire with 10 gauge from EFI fuse to EFI relay, and install 10 gauge wire from EFI relay to connector EB1 terminal #2."

And putting a new relay in at the same time sure seems like solid advice. Keep another spare handy, just in case...

 

[landtank]

Thanks for the link. Do you recommend replacing the entire wire harness or only the relay wiring to and from the fuel pump?

Just what the writeup says. 2 short pieces I beleive as I'm only aware of the problem but haven't actually done the repair.

 

[Africacruiser]

FANTASTIC!! Thanks all for the info. By the way, where precisely is the EB 1 terminal located? I don't have any of my tech manuals here.

Thanks

 

[landtank]

can't help you on that one, I have a 96 and would hate to give you inaccurate info. SOmebody later on will probably be able to help you.

 

[FrankTorres]

There is a 12 gauge wire, yellow with a red tracer that goes from the EFI relay to EB1. EB1 is the first connector about 12 inches from the EFI relay, that one needs to be changed to 10 gauge.
There is a 12 gauge wire, red with a yellow tracer that goes from the EFI fuse to the EFI relay, that needs to be changed to 10 gauge.

Good luck