LS400 wiring head ache.

[dantheman85]

Hi guys n gals.

I'm sure this has been asked and answered a thousands times before, but I cant find the answers I need anywhere. I've got an LS400 1uzfe 1992/3 with a 89661 - 50160 ecu. No immobiliser. 34 pin, 22 pin, 16 pin and 28 pin plugs. Its the 34 pin I need a diagram for. I've seen a few, but they don't match. On mine pin 2 is yellow and pin 3 is green both rear O2 sensors. Also, there are a number of plugs under/ behind the ecu that also go from the engine loom into the body loom, any chance of a pin out for these too?

Any help appreciated!
Thanks
Dan

 

[Bushwhacker]

http://www.lextreme.com/PDF/96ls41.pdf
http://www.lextreme.com/PDF/96ls42.pdf
http://www.lextreme.com/PDF/96ls43.pdf
http://www.lextreme.com/PDF/96ls44.pdf

 

[dantheman85]

thanks

Thanks for the speedy reply, but those diagrams do not match. My 34 pin plug has the rear O2 sensors on pins 2 and 3. This plug runs the ecu into the body loom so its also not likely to have injector grounds in it. Surely someone has seen this particular ECU before.

Dan

 

[Bushwhacker]

Weired, the O2 sensors always run from the 28 pin plug.

 

[dantheman85]

I do apologise. You're dead right. God knows why I said 34, it is indeed 28 pin. While most of the colours match, there are some differences. I just need to find out if these are important differences.

 

[pajman]

This isn't spot on but it helped me
https://docs.google.com/folder/d/0B...edit?pli=1&docId=0B8j37bh-PLpzQ2ZWbHFrREJ2bjQ
And this

 

[dantheman85]

Lexus shop manual

I downloaded the VSM from http://www.emanualonline.com/ for about £10. Its spot on for my ecu wiring. It also has torque settings and all the other useful info you would expect from a VSM. Im currently still in the dark as to what is in those multiplugs that go from the engine loom to the body loom. Nobody seems to mention them so I guess they are not that important. Cheers for your input guys.

Dan

 

[pajman]

The 28 pin plug is very important , if you look at the pic of what each wire does , such as constant 12 volts etc . If you have the plug you need to id the important wires to get the ECU to work. If you have no plug you can make female pinned tails to plug into the ECU .

 

[dantheman85]

Yea, I knew the 28 pin ecu plug would be important, its the other 3 or 4 plugs that were behind the ecu when i removed the loom.

 

[Bushwhacker]

Yea, I knew the 28 pin ecu plug would be important, its the other 3 or 4 plugs that were behind the ecu when i removed the loom.

If you're fitting the 1uz into a different vehicle, then it's just the four ECU plugs that you need.

 

[dantheman85]

Bit of an update. Got it all sorted. There are a fair few wires that I don't need but I'll leave these in place until I've been able to road test it to make sure I definitely don't need them before I thin the loom out. I did have one odd running fault. It would flood itself, by this I mean the injectors were at 80% duty cycle at tick over and run for about 30 seconds before stalling. It turned out I'd earthed the braiding in the rear lambda wiring - this, as I found out, is a very bad thing to do. Now it runs just dandy

 

[Jan Venter]

Dantheman85

Pinout for plug 28 pin 2 Y not important o2 sensor. Pin 3 grn o2 sensor not important. The only pins that is of consequense is pin 9 blk/org ignition switch.Pin 14 blk/yel ecu constant power. Pin 22 wht battery power switched. Pin 24 blk/ org Mrel EFI Relay turn it on