Rad1

I have a 94 ls 400, I replaced the fuel pump, it's getting fuel but won't start.......I'm by myself so I unhooked the ignition coil wires, turned the key to accessory just under the start spot... I took each coil and touched it to a grounded piece of metal and no spark, my question is does the starter have to be energized before there will be spark coming from the coil wire or is what I'm doing show me if there is spark to the coil ???

Yamae

The ignition doesn't start synchronizing with the starter engagement, you need to know.

While the engine is cranking, the ECU checks items that satisfy conditions to trigger the ignition system. Your car must be missing something such as signals from rotation sensors and the ECU disables the ignition. The important first step would be to check those signals.

Are the crank position sensor and the cam position sensors sending signals to the ECU? An oscilloscope would be preferred to check but the resistance check may be the way to go.

Sometimes a failed ECU causes the problem too. Have you checked the ECU? Old QAS capacitors kill the ECU very often.

Rad1

NO I have not done that..... I'm going to.. is that the box inside the car on the passengers side floor just below the dash ???

Yamae

The ECU is located just below the dash. This might help you.
https://www.clublexus.com/forums/ls-...capacitor.html