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Discussion Starter · #1 ·
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 :zzzzz:

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...
 

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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.
 

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Discussion Starter · #3 ·
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!
 

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Discussion Starter · #4 ·
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?
 

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Discussion Starter · #7 ·
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?
 

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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).
 

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wooooo thanks yall this will make my wiring soo much easier
 

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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.
 

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Discussion Starter · #11 ·
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).
I was thinking the same. According to the wire diagram thats what it looks like, and your correct, it seems to serve no perpose except for triggering the high/low speed relay, but I was worried because it appears to do that by changing the voltage going to said relay. so i was worried that If i removed it from the mix the fule pump would be running at reduced capasity and would hinder performance....
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.
yeah i thought the same thing too...
what im going to do is hook the cluster signal (im assuming that there is a diffrence with the pulses or voltage it feeds and the ecu wont like it).
but ill hook the cluster feed to it, if the issue shows ill sever the connection, if the issue is still there i will sorce out a speed sensor like Phil said...

He said that he has had a 30% success rait with these ecus without the speed sensor mod so hopefully ill be one of the luckey ones...
er, wait.... i dont think i remember he ever mentioning if he hooked that lead to any thing or not? he may have just had it dissconnected (putting it in a non toyota, or a toyota that dosent have a cluster signal wire)...

BTW just rigged up a Neutral safety kill switch :naughty:
What i did was "T" ed off a supra wire that was hot when ignition is in start position, ran it thru a switch, and ran that to the ECU.
In theory (because i havent tried it out yet) If the ECU sees more than 6v of power (switch closed) at that pin (NSW) when starting it will stop the works...
 

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I know it's an old thread but,


Finally did you wired a miata speed sensor?


If yes wich year? part number?


I'm in the same process and I have issues with the engine and everything is supposed to be fine, but I plugged nothing for the vehicule speed sensor.


FranK
 

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Frank two thing here. First the ghoul hasn't finished his swap and he is even selling the car unfinished. Second did you try wiring your actual SPD signal from your supra clusters? According to the MA61 diagram: http://www.cygnusx1.net/Supra/Library/TSRM/MK2/manual.aspx?S=E&P=5 there was already a L-W wire going to the 5M ECU. I don't know how the ECU is plugged in a MA61, but on a RA65 there's a 18 pin and a 14pin connectors that stay in the car when you take the engine out. The 18pin connector is like an intermediate between all the accesories and signal from/ to the engine and diagnostic plug. Find that blue and white wire.

If you need the "real" wiring diagrams of the cluster/engine I can ask Fred or Luc to send me the diagrams.
 

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I didn't noticed that the cluster had a wire who tells to the cruise control ecu the speed of the car!

I'll try this and i'll wire the BK input to the ECU of the 1uz, it could only help.


Because for now the engine doesn't idle very well and I got a really poor acceleration, poorer than my truck on 33" with the 22re:SM130 (1):


I hope theses wires will fixe my problem because I'm really tired of searching around to find what is wrong.
 

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Discussion Starter · #15 ·
Frank two thing here. First the ghoul hasn't finished his swap and he is even selling the car unfinished. Second did you try wiring your actual SPD signal from your supra clusters? According to the MA61 diagram: http://www.cygnusx1.net/Supra/Library/TSRM/MK2/manual.aspx?S=E&P=5 there was already a L-W wire going to the 5M ECU. I don't know how the ECU is plugged in a MA61, but on a RA65 there's a 18 pin and a 14pin connectors that stay in the car when you take the engine out. The 18pin connector is like an intermediate between all the accesories and signal from/ to the engine and diagnostic plug. Find that blue and white wire.

If you need the "real" wiring diagrams of the cluster/engine I can ask Fred or Luc to send me the diagrams.
yep, and yep...

I contacted Phill Bradshaw and he said that he once he started wireing the cluster in (as mentioned above) he hasnt had an issue...

Ill look over my info but i think the 1uz-fe has a two speed fule pump that is part of a fine ilde controle system..... I really dont remember, its been a few months since ive looked that info over...

that and wireing has never been a strong point of mine!
 

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I've just received your email and from what I can see there shouldn't be too many solutions. However it's hard to tell because I don't know how you did it.

If you don't have fire it could be a bad cam position sensor or a bad crank position sensor. Make sure the igniters are well grounded. The ECU ground is supposed to be in the engine bay around the rear of the passenger side head.

You did not mentionned if you had voltage to the cold start injector or the time switch (STJ and STJ1). Do you have fuel pressure and does the cold start injector fire? If you crank for a while do you get any fuel in the chambers? Did you took a plug off to verify that it fires or not.

Starting circuit take into account only a couple of sensors so it shouldn't be much. I think you forgot a lot of details in your pm. Does it crank does it fire? Do you have fuel in the rail and is there any injector firing?

If your lucky it will give you an error code. Plug E1 and TE1 and read the number of pulse: http://www.lexls.com/tutorials/intro/codereading.html
 

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Just want to tell you that if the cams sensors are bad it's supposed to fire anyway.

But if the Crank sensor is bad NOW you'll never have fire.


You're supposed to read 850-1350 Ohms at theses three sensors.


Have a good luck.
 
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