Hi Everyone, I am a brand new LS400 owner.

Long story short, I just bought a 1990 LS400 with 29,000 original miles. Car was stored in a warehouse since 1998, and has not been driven since. It was prepared for long storage, put on jack stands, fuel tank drained, and we are trying to bring it back to life.

We changed all the fluids, put in a new battery, and the car will CRANK, but will NOT FIRE. It sounds as if there is something electrical preventing it from starting. We measured the current at the fuel pump relay, and it IS NOT getting power.

In reading the very helpful forum, I am still a bit stumped and am looking for guidance.

One question is does this car, a 1990, have an factory alarm or immobilizer that would be preventing the no start?

Anything else obvious I am might be missing?

Thanks so much. I can't wait to drive this thing!

 

Check for power at the pump while cranking the engine and report back.

 

Thanks!

We checked for power at the fuel pump relay, while cranking and with the key on, and there is NO POWER.

We have not checked power at the actual pump yet, but we are don't hear anything and assume if the relay doesn't have power, neither does the pump.

We found a helpful diagram on this forum, and up stream from the fuel pump relay is the "circuit opening relay". We do have power to the circuit from the EFI main relay, (B+ on the circuit opening relay) but relay seems not be closing.

We jumped the circuit opening relay, and the car still did not start. We do not hear the fuel pump. We measure the current at 11 amps, seems like a lot of amps. Maybe the fuel pump is frozen?

Even if the pump is frozen, we are still confused as to why we are having to jump the circuit opening relay. It feels like there is something ECU related maybe preventing the car from starting.

 

Give the fuel pump power directly (disconnect from the main harness) see if it spins. Do you have a check engine light on with key on?

 

Check engine light DOES WORK with key on.

We are checking the pump right now, and will report back asap.

Thanks.

 

That's good means the EFI relay is working.

 

What a beauty you got there.

Do not touch the fuel pump!

Using a jumper wire, short check connector terminals FP and +B together. Turn the key ON, grasping the fuel inlet hose for fuel pump pulsation, if none then check fuel pump relay.

 

I appreciate all the ideas.

We jumped the connector at the FP and +B and we measured the current at 11.5 amps, and nothing coming out of the pump, and then we jumped the circuit opening relay, and got the same result.

We also applied 12 volts directly to the fuel pump from inside the trunk, with the fuel line cracked at the engine, and got nothing from the pump, and no signs of life.

So now I guess we are assuming the pump is seized and will move forward with replacing the pump, unless you kind experts have any other bright ideas.

The part that worries us is that we are still not seeing the relay closing to activate the pump, but maybe the car senses the over-current coming from the pump and stops it from doing more damage?

thanks so much

 

Jump TE2 and E1 connectors, turn the key ON, read the check engine flashes for codes.

Pins identification should be under the plastic cap cover if my memory still there.

 

11.5 amps is normal at the initial starting. The ECM will control the fuel pump resistor to lower the voltage while running.

Time for a new fuel pump unless you could get the fuel pump spinning again.

 

Can try applying power forward and backwards polarity over and over to try and get the pump moving. If that fails best of luck finding a quality replacement.

 

At 29K miles, your fuel pump isn't worn out, It's still a spring chicken.

If you have a laptop power supply that is laying around with output voltage ≥ 18V, you can try to unseized the fuel pump with it.

 

Not worn out but whatever fuel is left in the tank is no spring chicken the pump probably seized due to gas turning to varnish.

 

The tank was "drained" but now that we opened it up, there was probably enough left at the very bottom to seize the pump. Good times.

Followup question. The pump that came out of the car is Denso, and Lexus is telling us there is an Aisan replacement part. I am assuming that's fine... so here we go

 

Should be interchangeable since the rest of the components are the same. Aisan is very likely discontinued not the Denso (that may be as well) but specific dealers might have parts in stock that are not a part of the inventory system.

What does the filter sock look like? If it was me I'd replace it.