1uz ma61 wire in...i know this is supposed to be easy

[the ghoul]

I decided to go with the 92 ls400 ecu after all. I alreay have the wire diagram and a full uncut harness for it any how, so why not? that i picked one off of ebay for $50 shipped

so last night i sat down with my supra manual and my ls400 manual and got to pin 1 connector 1 and got stuck.... for like 3 hours.... i suck at this!!!

I know this is supposed to be an easy wire together, seeing how im not even going to be using the AC, much less any automatic trans/traction control/abs silly-ness...

I guess i just dont trust my self... if the connection is straight forward for both cars im fine, but if the diagrams dont look the same for some dumb reason I freak out and get paranoid...

Does any one have a wire up guide for a 1uz into a ma61? Ive found plenty for the ma70 but without a ma70 manual it doesn’t mean much to me...

so far all i could find on the issue was the manuals and this;
"In essence, all you need to worry about is the injector and ignitor/coil power, the ecu BATT, +B, +B1, IGSW, MREL pins and the efi relay, bypass the fuel pump and it should start (you can even get away with no BATT and MREL as long as you power +B and +B1 externally). It depends how complete and how neat you want it to be - there's a ton of other stuff that should be hooked up that isn't critical to it running."

I just dont want to jump in, do what i think will work and have it fry on me! I guess i just dont know enough about ecu inputs and outputs to pull this off confidently on my own...

[rwdfreak]

I need to recheck my wiring. Last winter I took the time to remove all of the uneeded wires (trust me there's a bunch). I cannot say it work because I'm still in the process of fitting the engine in the car, BUT I identified all of the wires at both ends and played enough with all the wires to know exactly what's going on. If I recal there isn't much to wire except:

-Circuit opening relay (1 ground, 1 to ECU, 1 from starter relay, from efi main relay and various EFI (through IL1 connector) and 1 to FC on ECU)
-Ignition main relay (2 grounds, 1 plus from 30A FL fuse, one to the starter, 1 on the main Black-Orange wire, 1 to the Black-Orange wire to injectors and igniters)
-Starter (trigger) you can use a starter relay and connect a kill switch or use the same wire from the 5M starter
-The alternator to the fuse box
-Tachometer (you'll need to find a way to split the signal as the 1UZ gives a 4 cylinder signal)
-Oil pressure to cluster
-Oil level to idiot light (cluster)
-Water temp to cluster

Then on the ECU itself
-plug neutral wires together (to make it think it's in Neutral)
-couple of grounds
-FPR to fuel pump/circuit opening relay)
-BK to brake light
-W to check engine
-Mrel to EFI main relay
-Batt to a EFI 20A fuse.
-Secondary O2 sensors.

Those are the notes I've taken during the process. I'm using Lexus wiring diagram. If you are using the haynes wiring diagram on Lextreme no wonder you are lost because there's a bunch of errors in it.

This is for a 1991 Lexus LS400

BTW you need to make sure the secondary TPS for the trac is in open position otherwise the engine won't run properly.

That's about all I can think of. The rest is either not connected to the ECU or useless on the engine operation.

[the ghoul]

ill post up what i did last night but alot of what you said is spot on to what i got...
Im using the lexus factory service wire diagram and also the supra one.
Im glad you mentioned the FC pin on the ECU last night i was unsure of if i was to connect that or not, but because the circut open relay circuts were near identical between the two cars, i felt it was a no brainer!

thanks for the tip on the secondary TPS... I never would have caught that one!

[the ghoul]

ok back on track.
Per the 84 supra factory wire manual, and the 92 ls400 one this is what i have so far. I will do my best to find the correct wire diagrams digitally *already have the supra one* and make corrections to refelct what im trying to say here...
*dissreguard the ecu spd pin.... im currently working on getting info on a speed sensor simulator that will trick the 92ls400 into working properly*

this look about right to any one?

[the ghoul]

Then on the ECU itself
-Batt to a EFI 20A fuse.

on mine i used the 15A stop feed for this simply because its right there at the supra connector already...

[the ghoul]

so in my world thats....

-plug neutral wires together (to make it think it's in Neutral)

IL1 pin 8 B <>Il2 pin 6 B-W

-W to check engine

U pin 19 L-R <> E11 pin 5 Y-R

[the ghoul]

geeze....
tried a diffrent approche and copied then highlighted all the connections and circuts missing when the engine wire harnesses, and ecu were removed from the LS400, than found the exact replacements *ish* from the supra....
and ended up with a layout that requires making a bunch of connections that were not a part of the orrigional supra wire....

but i feel more confident in this one than i do the last
stuff in red is things i know i dont need.
do i need the one in yellow?

[rwdfreak]

I'm 99% sure the only function of the FPR is to tell the fuel pump relay that the engine is idling and that the pump can run at low speed. I think it only work if you are using the LS400 fuel pump with dual speed mode.

And yes the LS400 fuel pump work at different speed. Probably to make as less noise as possible when not needed (keep in mind the pump is inside the car behind the rear seat).

[moonpie33]

wooooo thanks yall this will make my wiring soo much easier

[rwdfreak]

I still don't get why you'd need a miata speed sensor. The Supra/Celica OEM dash already feed the OEM ECU with a speed signal. I know that the cruise control on the LS400 use two speed sensor in the tranny that measure the amount of slipp. I do not have the cruise control diagram, but I cannot see how much of diference it would make to directly plug the speed sensor from the Supra dash.

However I must admit that Phil Bradshaw has probably more experience than I do with the factory 1UZ ECU.