Alright im a noob and im not sure what to to with my lsu 4.9 wire 4 i have googled and searched here but i just get more confused.
Once and for all, do i connect it straight to G18 or to G18 with a 3A fuse?
The car is a mk4 supra and from what i know there is a 7.5A fuse from oem that now is connected to G18. I also got the pnp 2jz gte if it matters. Emu black
Thanks in advance and sorry for asking stupid questions!
Why G18? Connect it to battery with a fuse. Emu is switching ground.
Hey Mark, welcome!
I would recommend using a 3A fuse on that wire to the WBO heater. However, I do not recommend connecting pin 4 to G18. The wire G18 to the EMU black is not suitable for WBO heater power.
Pin 4 on the LSU 4.9 connector should go to a separate power source that provides 12V when the ignition is switched on and stays on during cranking. Examples of where power could come from include power to the injectors or the ignition coils.
Another solution is a separate relay with a fuse to feed the heater power (pin 4). This relay could feed the WBO heater as well as a boost solenoid for example. Anything else that should have switched power while the engine is cranking as well as running.
Hope this helps.
the wideband just needs a nice stable power supply to work it doesnt matter where you get it.
Im going for the last alternative, relay switched by g18 and a 3A fuse from battery T off before my 5A fuse to B13 since everyone has a different answer and it seems to be very important to have good power to pin 4
G18 just receives a switched 12V for the ECU to turn on.
5A fuse to B13? It should have a 20A fuse (main ecu power).
Like @ngt said, Pin 4 just needs a stable power supply. Switched +12V from battery with a 5A fuse.
Ah, got you, was confused when I saw the 5A. 20A is from their wiring example. A bit of discrepancy between the manual and diagram but I went with the 20.
EMU Black - Wiring Example 4 Cylinder.pdf (334.4 KB)
And the training manual has 3A recommended for the Wideband but I’ve always used a 5A. Either way.
Good that you said something because i had to check what i actually put in the car and it was 10A
Where do you take switched power for pin 4 then?
Haha it happens.
I used a 120A relay (overkill) to power 1/2 of a split fuse box (1/2 is switched 12V, 1/2 is constant).
It was impractical to run a larger direct wire from the IGN switch to this location, so I just used a small tap from it to trigger this relay.
All my powered wires come from this fuse box (and a separate relay box).
