Symptoms
You flick the sub-tank switch, the sub-tank light comes on, but the main-tank gauge keeps falling.
The fix, step by step
- On the 1KZ-TE, the lift pump is part of the injection pump, so the lines between tank and pump are under vacuum.
- An IH8MUD member suggests starting at the fuel-tank switch-over valve (he found it listed as Toyota 77710-60040): check that it gets power when you flick the switch, and that it actually changes over.
- AustralianCar.Reviews warns that a sub tank that was never used can seize its switching mechanism and leave stale fuel behind, so drain old fuel before you trust it.
Tools & part numbers
- Multimeter
- wiring diagram for your engine (petrol and diesel circuits differ)
- fuel-safe catch can
Where to buy the parts
Toyota fuel tank switch-over valve 77710-60040 (confirm by frame number)Amayama (OEM) ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Toyota Land Cruiser Prado 90 parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.