HARD START/EXTENDED ENGINE CRANK AFTER OVERNIGHT SOAK
VEHICLES AFFECTED: 1990 C, E, K - 4.51, V-8 VIN CODE 3,8
Some Devilles, Fleetwoods, Eldorados, and Sevilles may experience a condition of a hard start or an extended engine crank after an overnight soak. This condition may be caused by the fuel pressure regulator.
To diagnose this condition use the following procedure:
1. Connect a 0-700 KPA (0-100 psi) fuel pressure gauge, J-34730-1, to the fuel pressure test port (Schrader valve).
2. Key on for two seconds to energize the fuel pump. Note fuel pressure. Key off for five minutes and recheck fuel pressure.
If the Euel pressure is 275-345 KPA (40-50 psi) at key on and holds fuel pressure, then refer to the appropriate Service Information Manual, Section 6E, Subsection B, under the symptom "Hard Start".
3. If the fuel pressure drops, enter diagnostics and select ECM injector override, E.5.4 for DeVille and Fleetwood, or ES04 for Eldorado and Seville. Use the injector override to diagnose a leaking or stuck-open injector. Repair as necessary. For more detailed information on the override feature, refer to Section 8D of the appropriate Service Information Manual.
4. On DeVilles and Fleetwoods key on for ten seconds, then restrict the rubber section of the fuel return line at the fuel tank. Note fuel pressure, then key off for five minutes. If the fuel pressure still drops, then check ball in the fuel pump is not seating. Replace the fuel pump.
On Eldorados and Sevilles connect available tool J-37287-1, or equivalent, into the fuel return line. Key on for ten seconds, then rotate the shut off to the closed position. Note fuel pressure, then key off for five minutes. If fuel pressure still drops, the check ball in the fuel pump is not seating. Replace the fuel pump.
5. If the fuel pressure now holds with the key off and J-37287-1 or equivalent connected, then the fuel pressure regulator is leaking and must be replaced.
The fuel pressure regulator service procedure in the 1990 Service Information Manual refers to a tool, J-38458, for removing the pressure regulator base screw. It is anticipated that this tool will be shipped to dealers in mid-April. Until the tools are shipped, the following procedure should be used when removing the pressure regulator:
1. Disconnect negative battery cable.
2. Remove air cleaner upper housing.
3. Relieve fuel pressure using the procedure in Section 6E-C2 of the appropriate 1990 Service Information Manual.
4. Remove serpentine belt.
5. On federal equipped vehicles (option code NA5), remove AIR pipes and position out of the way.
6. Remove power steering pump and bracket and position out of the way. For the removal procedure, refer to Section 3B3 of the appropriate Service Information Manual.
7. Remove PCV line and vacuum line to the pressure regulator valve.
8. Remove the accelerator cable, cruise control cable, and TV cable and bracket.
9. Disconnect the electrical connectors at the TPS, ISC, coolant, and MAT sensors.
10. Disconnect the coolant hose to the thermostat housing.
11. Disconnect the fuel feed line from the rear fuel rail assembly. Discard O-ring.
IMPORTANT: On reassembly lubricate the new O-rings with petroleum base grease, and torque the fuel feed and return lines to N-m (22 ft.lbs.). Use a backup wrench to prevent damage.
12. Disconnect the fuel return line. discard O-ring.
IMPORTANT: Wrap a shop cloth around the fuel lines to collect fuel. Place cloth in an approved container.
13. Remove EGR vacuum lines and EGR valve.
14. Remove five fuel rail support bracket attaching bolts.
15. Remove electrical connectors at front and rear fuel rail assemblies.
16. Remove fuel rail assembly from intake manifold.
17. Remove pressure regulator base screw.
18. Remove lower O-ring seals from fuel injector assemblies and discard.
IMPORTANT: On reassembly lubricate the new O-ring seals using petroleum base grease.
19. Reverse the above procedure to install.
PARTS INFORMATION
Fuel Pressure Regulator Kit ................ 17112324 (includes pressure regulator and fuel feed and return line O-rings)
Injector Lower O-Ring Package .............. 17112328
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
