Remedial wiring (99' GS400)

Spinnetti

Member
Did a motor swap in my 91' LS from a 99' GS, including complete engine, trans and most of the wiring harness, including the cluster, Immo, key, ECU etc.

So I plugged everything in I could, and dash lights up, but not sure:
1. What are the symptoms of the Immo saying "no"? - When I turn the key, the Starter doesn't kick, and the fuel pump never kicks on is that related?
2. Is there maybe a shifter switch I'm missing that would prevent the pump and starter going? On my other cars, when you put the ignition on, the fuel pump runs, but this doesn't happen (no voltage). Pretty sure the wiring and relays are right to the pump, so I suspect the ECU is saying no for some reason.

There's so much wiring I'm a bit overwhelmed.. the complete engine & trans harness and main fuse box is all there and untouched. Ug. I so want somebody to wire this thing from "cold". If I can get it to run, I can figure out all the other circuits.

https://www.amazon.com/photos/share/d4Yntjv47IbsvqBW1tRuQR8iYMUk3k3qkrwEUOTgUgu
 

George_R

Member
Connect LED to IMLD pin of ecu
It should blink when ignition is off, and stop blinking right after you turn the key
If it keeps on blinking, immo says no
 

Spinnetti

Member
Connect LED to IMLD pin of ecu
It should blink when ignition is off, and stop blinking right after you turn the key
If it keeps on blinking, immo says no
Thanks George... Does it require trans in park and or foot on brake? If so, I'll need to figure how to fake the park sw.
 

George_R

Member
Yes it does but ECU will happily start without them wired properly (ECU would even start the engine if you have half of coils,injectors connected and only crank angle sensor signal available)
 

Spinnetti

Member
Yes it does but ECU will happily start without them wired properly (ECU would even start the engine if you have half of coils,injectors connected and only crank angle sensor signal available)
so if I find the right pins, I can short them at the ecu to ignore the trans switch at least? Basically the fuel pump and starter won't run and not yet sure why.
 

Spinnetti

Member
You don't need to short anything
ECU doesn't look at trans switch for starting
Good to know. That will save some searching... it doesn't crank and fuel pump doesn't run, though the dash lights up. Hmm. I suck at wiring lol. I may just buy another damn Lexus so I can work out the loom in a stock car to see what I missed. ugg.
 

Guillaume Jordaan

New Member
If it is auto box which was replaced with manual box you will need to bridge out the inhibitor switch wiring for it to crank. The wire from the ignition side allowing the engine to crank only when in park or neutral. If you still running the auto box the inhibitor switch might be faulty.The fuel pump must switch on when the ignition is switched. If not check the fuel pump relay and give the fuel pump 12V+ power direct and check if the pump is working.
 

Guillaume Jordaan

New Member
Did a motor swap in my 91' LS from a 99' GS, including complete engine, trans and most of the wiring harness, including the cluster, Immo, key, ECU etc.

So I plugged everything in I could, and dash lights up, but not sure:
1. What are the symptoms of the Immo saying "no"? - When I turn the key, the Starter doesn't kick, and the fuel pump never kicks on is that related?
2. Is there maybe a shifter switch I'm missing that would prevent the pump and starter going? On my other cars, when you put the ignition on, the fuel pump runs, but this doesn't happen (no voltage). Pretty sure the wiring and relays are right to the pump, so I suspect the ECU is saying no for some reason.

There's so much wiring I'm a bit overwhelmed.. the complete engine & trans harness and main fuse box is all there and untouched. Ug. I so want somebody to wire this thing from "cold". If I can get it to run, I can figure out all the other circuits.

https://www.amazon.com/photos/share/d4Yntjv47IbsvqBW1tRuQR8iYMUk3k3qkrwEUOTgUgu
Hi bud. I see you are using the engine with the front engine harness. Mine is the "rear engine harness" Be patient I will try and assist as best I can. Just want to go do some homework and compare a few things and then I will be in contact. My email address is [email protected]. I think we will be able to communicate easier.
 

Spinnetti

Member
Thanks for the help... I finally got it running, now working on getting the cooling fans to work like I want, and simplifying the rear brake lights (getting rid of the light out sensor and only running two lights in back). I have the fuel pump running in a coffee can right now as I try to figure out how to marry it to the stock LS400 gas tank. Maybe just mount it in a surge tank?
 
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