93 Lexus LS400/Toyota Celsior EFI Fuse parasitic draw

[saukeye]

Sorry but this is a cross post from ClubLexus that I haven't received an answer to, but I feel like I'm SO close to solving and it's driving me mad...

I have a 1993 Toyota Celsior that I purchased about a year ago. Recently, after driving two hours to the airport and returning from a 2-day trip, my Exhaust Temperature warning light/CAT came on out of the blue while starting up my car. Reluctantly, I drove the 2 hours back home with no issues. Come 2 days later, while going to work, I stuck my key into the ignition and *clickclickclick...* the battery was dead and I had to ask a family member for a ride to work. Determined to find an answer, I came across the SoarerCentral forums and an issue similar to mine came up regarding the CAT light only to come to the conclusion that my alternator and ECU were going. So, I took the time to ship off my ecu for a rebuild and find a quality used Denso alternator and repladed my old one, only to find out that the problem persisted! (I know, I should have done this first) I finally checked the fuses and noticed the EFI fuse was drawing 1.3 amps with the car turned off and the EFI main relay felt like the surface of a frying pan over fire! Hot!

Does anyone out there have a similar issue to mine or a possible solution?

[Jeremy M.]

The relay really should be shut off, disconnecting power when it's not being activated. I'd check that the relay is functioning as expected by jumping power to the switch side and testing for continuity on the load side, and making sure it shuts off with no power to the switch side. You should also hear an audible "click". 

If the relay looks to be working fine, I'd look for a wiring diagram next, and find anyplace where power could be shorting to the relay to keep it in the "on" position.