Start With Pressure, Not Parts

Most RZ running complaints that get blamed on injectors are fuel pressure problems, and pressure is the one thing you can measure rather than guess at.

The fuel pressure gauge kit answers it directly and comes with everything needed to fit it. Use fuel-safe Teflon tape or Permatex PermaShield on the threads — ordinary thread sealant is not adequate here.

Injector Cups — Different on This Engine

This catches out people who have worked on older Toyota fours.

On the RZ engines the fuel injector cups sit directly in the cylinder head casting, not in the manifold as on previous generations. They give the OEM injector a sealed seat — and after years of under-hood heat cycling they harden and stop sealing.

The injector cup and O-ring set is the fix, and cheap insurance any time the head is off. Reusing worn cups is how you end up with a vacuum leak you cannot find.

Injector seals

The O-ring, grommet and isolator kit covers four injectors. It will not work on 3VZ or 5VZ engines, and the cap end is sold separately in two styles depending on your year.

Connectors and Filters

The injector connector solves a problem every one of these trucks eventually has: the plastic locking tab snaps and someone reaches for the RTV. This one uses a different locking arrangement.

The fuel filter is the most overlooked tune-up part on this engine. Consider what it filters — a twenty-five to thirty year old steel tank with debris in it. If you cannot remember changing it, change it.

Standalone Management

Fitting the LC Pro Fuel Injection System? The hall sensor mount locates the Hall effect sensor to take a signal off the crank pulley.

Standalone management is the right answer once you are past what the factory ECU can adapt to — a high boost supercharger, a turbo kit or a Stage 3 and above camshaft. Below that the factory computer copes better than people expect, and the Stage 1 camshaft is specifically designed to run on it.

Diagnosing in the Right Order

  1. Measure fuel pressure. Everything else is guesswork until you have.
  2. Change the filter if its age is unknown.
  3. Check for vacuum leaks — throttle body gasket and injector cups are the usual culprits. See Intake & Throttle Body.
  4. Check the TPS adjustment before replacing sensors.
  5. Then injectors.

Tell us the symptoms and what you have measured and we will help you work through it.

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