Fuel Pressure Requirements For Toyota 22Re Engines

The fuel pressure for a Toyota 22RE engine is typically around 43 psi, with a maximum pressure of about 70 psi. However, some sources suggest that the fuel pressure can vary depending on various factors, such as the type of fuel pump and carburettor being used, as well as the presence or absence of a return line. For example, one source mentions that the stock mechanical fuel pump for a 1987 22R engine is around 8 psi, while another source mentions that the fuel pressure for a Weber carburettor is between 2.5 and 3 psi. It is important to ensure that the fuel pressure is within the appropriate range to avoid issues such as a rich fuel mixture or violent engine starts.

Fuel pressure regulators

The primary function of a fuel pressure regulator is to maintain stable fuel pressure by managing excess fuel. This is achieved through two main types: return-style and non-return-style regulators. Return-style regulators allow excess fuel to return to the tank, ensuring a consistent supply to the engine. In contrast, non-return-style regulators maintain pressure without returning excess fuel.

Adjustable fuel pressure regulators offer tailored performance, allowing fine-tuning to achieve the perfect balance of fuel efficiency. This is especially beneficial for high-performance race cars and reliable daily drivers. Additionally, fuel pressure regulators with return lines enhance stability by effectively managing excess fuel, maintaining steady pressure across varying engine loads, and preventing fuel starvation or flooding.

When selecting a fuel pressure regulator, it's important to consider the regulator pressure range, which can be high pressure (above 20 psi) or low pressure (below 20 psi). The regulator pressure, mounting style, and boost or vacuum reference port are also crucial factors in choosing the right regulator for your vehicle.

Regarding the Toyota 22RE engine, there are varying opinions on the ideal fuel pressure. Some sources suggest that a fuel pressure of 44 psi may be too high, while others mention that the stock mechanical fuel pump for the 1987 22R engine operates at 8 psi, which can be adjusted down to 3-4 psi with a regulator. It's important to consult a professional or refer to manufacturer guidelines to determine the appropriate fuel pressure for your specific vehicle.

Injectors

The Toyota 22RE engine's fuel injection system is relatively basic compared to modern EFI engines. The injectors are always energised on one side, and the ECU provides a ground to allow them to fire and squirt fuel into the engine.

There are known issues with the injectors on the 22RE engine. One issue is that the injectors can leak, causing fuel contamination in the oil. This can be diagnosed by connecting a fuel pressure gauge and watching the pressure after the engine is shut off. If the pressure does not hold above 21 psi for at least 5 minutes, then the injectors may be leaking. Another way to test for leaks is to crimp off the fuel lines after shutting off the engine and observe if the pressure drop can be controlled. If the injectors are leaking, the pressure drop will not be controllable.

Another issue with the 22RE injectors is that they can become stuck open, causing the engine to flood with fuel. This can be dangerous and may result in the engine catching on fire.

It is also important to note that there are different types of injectors for the 22RE engine, depending on the year of the engine. Early engines used "low" impedance injectors with a resistance of around 2 to 4 ohms, while later engines used "high" impedance injectors with a resistance of around 12 to 14 ohms. Using the wrong type of injector can damage the ECM, so it is important to use the correct injectors for your specific engine.

Upgraded injectors are available for the 22RE engine, offering better fuel atomisation and improved performance. However, it is important to ensure that the injectors are compatible with the OEM ECM and that the fuel flow is not too high, especially at startup, as this can cause starting issues.

Fuel pump issues

There are several issues that can arise with the fuel pump of a Toyota 22RE engine. One common problem is a failure to start the engine, with the starter motor simply whirling over indefinitely. This can be caused by a faulty fuel pump, but it may also be due to a problem with the electrical system, such as a blown fuse, a bad ground, or a broken wire in the harness.

To diagnose a potential fuel pump issue, it is important to check for power at the fuel pump connectors. If there is no power, the issue may lie in the electrical system. If the pump is receiving power but still not functioning, it could be faulty and may need to be replaced. It is also worth checking the fuel rail to ensure that fuel is reaching the injectors.

Another issue that can indicate a failing fuel pump is excessive noise. A pump that is not running consistently, with RPMs that fluctuate, may be nearing the end of its life. It is important to note that fuel pumps tend to last longer if they are kept cool by being submerged in fuel. Running the pump when the fuel tank is low can shorten its lifespan.

In some cases, fuel pressure may be too high. This can cause a violent start, with the engine shaking and running rough at idle. However, high fuel pressure typically results in a rich fuel mixture, rather than a lean condition. If you are experiencing a lean condition, it is more likely that there is an issue with the fuel pressure regulator or a problem with one or more of the injectors.

It is also worth noting that working on the fuel system can be dangerous, as fuel is highly flammable. Always exercise caution and ensure that there are no potential sources of ignition when working on the fuel system.

Rough idle

A rough idle can be caused by a wide range of issues. It could be a problem with the fuel injection system, which has a lot of sensors and working parts that need to be in harmony for a smooth idle.

First, check for any vacuum leaks. You can do this by spraying some soapy water or carb cleaner on the vacuum lines and checking if the RPM drops. If there is a leak, you will pull water into the engine. You can also try using a propane bottle with a hose to probe around for leaks, and you will hear a change in the engine sound when you find one.

Next, check the choke is adjusted properly. If the idle is too low, raise it to 800-900RPM on the carburettor. Check the timing before making any adjustments to the mixture or air/fuel ratio. A bad distributor will cause the engine to stumble and fall on its face when trying to rev up.

You can also try adjusting the timing and driving the car to see if that helps. Some motors run better at 2 degrees over or under the specified timing, so it is worth experimenting.

Other things to check include:

• AFM (the cog inside adjusts the mixture while driving, and the screw under the plug adjusts the idle)
• O2 sensor
• TPS
• CSI
• CSI Switch
• ECU
• Temp Sensor
• Wiring to any of the above
• Fuel Pump
• FPR (Fuel Pressure Regulator)
• Fuel Filter
• Valves
• Head Gasket
• EGR
• PCV system
• Catalytic Converter
• Injectors
• Compression
• Ignition
• Exhaust leak
• Intake manifold gasket
• Flex tube going into the manifold
• Valve cover

Fuel line plumbing

The fuel pressure for a Toyota 22RE engine should ideally be in the range of 38 to 44 psi. At idle, the fuel pressure should be around 37-38 psi with vacuum and 44 psi without.

Now, for the fuel line plumbing.

First, you'll need to determine the size of the fuel line you require. For a 22RE engine, the stock fuel line size is 5/16 feed and 1/4 return. You can also use 3/8 or 1/4 hard lines, which will be sufficient for the engine's fuel consumption and demands.

Next, you'll need to decide on the type of fuel line you want to use. You can choose between hard lines or soft lines. Hard lines, typically made of metal, act as a heat sink and help prevent vapor lock. Soft lines, on the other hand, are usually made of rubber or braided hose and are more flexible for routing.

If you're using a carbureted engine, you may need to modify the fuel line routing. You can cut and flare the lines to fit your new setup or use adapters to connect different line sizes and types. For example, you can use metric reverse flare to AN fittings or convert between metric and standard reverse flare fittings.

When replacing the fuel lines, it's important to ensure that all connections are secure and sealed properly to prevent leaks. You can use flare fittings, compression fittings, or EFI hose clamps, depending on your setup.

Additionally, consider the location of the fuel pump and regulator. The fuel pump may be located inside the fuel tank or externally, which will impact the routing of the fuel lines. The regulator controls the fuel pressure, and you may need to adjust it to achieve the desired fuel pressure.

Finally, pay attention to the fuel filter and any other components in the fuel system, such as the pulse damper. Ensure that they are clean and functioning properly to maintain optimal fuel flow and pressure.

Remember to consult a professional mechanic or a trusted workshop if you're unsure about any part of the process.

Frequently asked questions