Checking Fuel Pressure
- Relieve fuel pressure. On 2.0L and 2.0L Turbo, remove throttle body bracket. On all models, wrap fuel lines with shop towel and disconnect high pressure fuel line at fuel rail. Install Adapters (MD998709 and MD998742) between fuel rail and high pressure fuel line. Connect fuel pump pressure gauge.
- Connect negative battery cable. Apply battery voltage to fuel pump check terminal to activate fuel pump. See Fig 1 . Check for fuel leaks. Disconnect battery voltage from check terminal. Start engine and let idle.
- Measure fuel pressure with fuel pressure regulator vacuum hose disconnected. Measure fuel pressure with fuel pressure regulator vacuum hose connected. See FUEL PRESSURE SPECIFICATIONS table.
- Increase engine speed to 2500-3000 RPM 2-3 times. Ensure fuel pressure does not drop when engine returns to idle. Check for fuel pressure in fuel return hose by gently pinching hose (with hand) while raising engine speed. There will not be any fuel pressure in return hose if fuel volume is low.
- If fuel pressure is too low during test, check for clogged fuel filter, faulty fuel pressure regulator or faulty fuel pump. If fuel pressure is too high, check for bent or clogged fuel return hose or faulty fuel pressure regulator.
- If fuel pressure is the same when fuel pressure regulator vacuum hose is connected and disconnected, check for clogged or broken fuel pressure regulator vacuum hose or faulty fuel pressure regulator.
- Stop engine and check for change in fuel pressure. Fuel pressure should not drop. If fuel pressure drops slowly after engine is stopped, replace fuel injector. If fuel pressure drops immediately after engine is stopped, replace fuel pump.
NOTE:
Some 1991 Laser and Talon models with 2.0L engines were built without a fuel pump check terminal. To check fuel pressure and fuel pump operation on these models, remove right center console cover. remove control relay. Connect battery voltage to wire harness side of control relay terminal No. 2. See Fig 1
. Fuel pump should activate. For further information please refer to T.S.B. No. 08-18-91.
FUEL PRESSURE SPECIFICATIONS
| Application | psi (kg/cm2 ) | ||
|---|---|---|---|
| 1.8L & 2.0L | |||
| W/Vacuum Hose Connected | 38 (2.7) | ||
| W/Vacuum Hose Disconnected | 47-50 (3.3-3.5) | ||
| 2.0L Turbo | |||
| Man. Trans. | |||
| W/Vacuum Hose Connected | 27 (1.9) | ||
| W/Vacuum Hose Disconnected | 36-38 (2.5-2.7) | ||
| Auto. Trans. | |||
| W/Vacuum Hose Connected | 33 (2.3) | ||
| W/Vacuum Hose Disconnected | 41-46 (2.9-3.2) | ||