Engine cranks but will not start

Tiny
AKIDROSKE
  • MEMBER
  • 2001 LEXUS IS 300
  • 3.0L
  • 6 CYL
  • AUTOMATIC
  • 261,000 MILES
Good Afternoon,

I received this car from a friend who was test driving it to sell it and it shut off on the test drive. He was able to start it up again and make it home (a few blocks away). He assumed the issue was the fuel pump and replaced it. We determined it was a fuel/fuel power issue, because the car started with Starter Fluid. I used a multimeter and determined that neither the pump nor the relays were receiving power when the car was in the "on" position.

I have:
- Replaced the fuel pump.
- Determined no power is reaching the fuel pump or fuel pump relays.
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Monday, May 3rd, 2021 AT 11:10 AM

1 Reply

Tiny
KASEKENNY1
  • EXPERT
Here is a guide that will help with this:

https://youtu.be/dCjmRL3p4Cs

However, if the engine starts on fluid and no power to the pump then we need to trace down where the power went.

This is going to get confusing as you have 3 relays involved, one feeding the next so here is the process going backwards through the system from the pump.

So the pump is feed from the Blue/red wire on the fuel pump relay. When the ECM wants this relay on, it grounds the green/red wire and it closes the relay to send power to the pump.

However, the relay gets the power from the green/white wire from the circuit opening relay. This relay gets it voltage from the ignition fuse and is again grounded by the ECM on the green/yellow wire. When it is grounded the relay closes and sends power it gets on the Black/red wire from the EFI relay.

The EFI relay get its voltage sent to it from the ECM to close the relay on the black/orange wire. Once it is closed it sends this voltage on the Black/red wire to the opening circuit relay. The EFI relay gets the power from the EFI fuse so we need to check that as well.

Please see the wiring diagrams below but we need to check these relays and fuses as well.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Let us know what questions you have. Thanks
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Tuesday, May 4th, 2021 AT 3:41 PM

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