Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2002 Mitsubishi Lancer LSFACTORY OEM SERVICE PROCEDURE
Fuel Pressure
WARNING:
Before disconnecting high pressure fuel hose at fuel delivery pipe, cover fuel hose connection with a rag. Some residual fuel pressure may still be in system.
- Relieve fuel pressure. See RELIEVING FUEL PRESSURE . Disconnect high pressure fuel inlet line at fuel rail. Connect fuel pressure gauge with Adapters (MD998709 and MD998742) between fuel rail and high pressure fuel inlet line. See Fig 1. Use scan tool to operate fuel pump. Ensure no fuel leaks are present.
- Start engine and allow it to idle. Measure fuel pressure with vacuum hose connected to fuel pressure regulator. Record fuel pressure reading. See FUEL PUMP PERFORMANCE . Disconnect vacuum hose from fuel pressure regulator and plug vacuum hose end. Record fuel pressure reading.FUEL PUMP PERFORMANCE
Application At Idle W/Vacuum - psi (kPa) At Idle W/O Vacuum - psi (kPa) All Models 38 (270) 47-50 (330-350) - Race engine several times. Fuel pressure should not drop. Check that fuel pressure is present in fuel return hose by gently squeezing hose while racing engine. If fuel volume is low, fuel pressure in return hose will not be felt.
- If fuel pressure is lower than specification, fuel pressure drops when racing engine, or no fuel pressure in fuel return hose can be felt, check for clogged fuel filter, faulty fuel pressure regulator or fuel pump delivery pressure.
- If fuel pressure is greater than specification, check for a faulty fuel pressure regulator or plugged fuel return line. If fuel pressure does not change when vacuum hose to regulator is connected or disconnected, check for a leaking or clogged vacuum hose to fuel pressure regulator, or faulty fuel pressure regulator.
- Stop engine. Observe fuel pressure reading for 2 minutes. Pressure should hold steady. If pressure drops sharply immediately after engine is stopped, the check valve in fuel pump is stuck open. If fuel pressure gradually drops after engine is stopped, restart engine and bring fuel pressure back up.
- Stop engine. While observing fuel pressure, squeeze fuel return line closed to check for fuel regulator as source of leak down. Squeeze high pressure fuel inlet line closed to check for fuel pump check valve as source of leak down. Squeeze both lines closed to check for injectors as source of leak down.
- When fuel pressure test is complete, repeat fuel pressure release procedure before disconnecting fuel pressure gauge. Install NEW "O" ring at end of high pressure fuel inlet line. Connect high pressure fuel inlet line to fuel rail. Tighten bolts to 44 INCH lbs. (5 N.m). Use scan tool to operate fuel pump and check for fuel leaks.
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
Comes to youSame-day available12-month warranty
Get a Free QuoteNo obligation. See pricing before you book.