95 jeep 4.o L-what is the fuel line pressure be?

FUEL SYSTEM PRESSURE TEST

The fuel system is equipped with a vacuum assisted

fuel pressure regulator (Fig. 8). With engine at

idle speed, system fuel pressure should be approximately

214 kPa (31 psi) with the vacuum line connected

to the regulator. With the vacuum line

disconnected from the regulator, fuel pressure should

be approximately 269 kPa (39 psi). This is 55-69 kPa

(8-10 psi) higher.

(1) Remove the protective cap at the fuel rail (Fig.

7). Connect the 0-414 kPa (0-60 psi) fuel pressure

gauge (from Gauge Set 5069) to test port pressure fitting

on fuel rail (Fig. 9).

(2) Note pressure gauge reading. Fuel pressure

should be approximately 214 kPa (31 psi) at idle.

(3) Disconnect vacuum line (hose) at fuel pressure

regulator (Fig. 8). Note gauge reading. With vacuum

line disconnected, fuel pressure should rise to approximately

269 kPa (39 psi).

Fuel pressure should be approximately 55-69 kPa

(8-10 psi) higher with vacuum line removed from regulator.

If not, inspect pressure regulator vacuum line

for leaks, kinks or blockage. If vacuum line checks

OK and fuel pressure does not rise approximately

8-10 psi after disconnecting vacuum line, replace fuel

pressure regulator.

The fuel pressure regulator is not adjustable.

(4) If fuel pressure exceeds 45 psi, check fuel return

line/tube for kinks or obstructions.

If the previous tests checked good, fuel pump pressure

is correct. If pump pressure was low, proceed as

follows:

(5) Release fuel system pressure. Refer to the previous

Fuel Pressure Release Procedure in this group.

(6) Disconnect the 5/16 inch fuel return line quickconnect

fitting at fuel rail. For procedures, refer to

Fuel Tubes/Lines/Hoses and Clamps. Also refer to

Quick-Connect Fittings. These can be found in the

Fuel Delivery System section of this group.

(7) Connect Fuel Line Pressure Test Adapter Tool

number 6539 (5/16 in.) between the disconnected fuel

return line and fuel rail (Fig. 10).

(8) Connect a 0-689 kPa (100 psi) pressure gauge

to Adapter Tool 6539.

WARNING: THE FUEL SYSTEM PRESSURE IN THE

FOLLOWING TEST MAY EXCEED 100 PSI. BEFORE

STARTING TEST, VERIFY GOOD CONNECTIONS AT

ENDS OF ADAPTER TOOL 6539. BE SURE TOOL IS

LOCKED ONTO FUEL RAIL AND FUEL RETURN

LINE. PULL FIRMLY ON ENDS OF TOOL TO VERIFY.

(9) To activate the fuel pump and pressurize the

system, obtain the DRB scan tool. Refer to the appropriate

Powertrain Diagnostic Procedures service

manual for DRB operation.

(10) MOMENTARILY pinch the rubber hose portion

of adapter tool 6539. Pressure should rise to approximately

75 psi within two (2) seconds. DO NOT

pinch hose for longer than three seconds.

If fuel pump pressure rises to approximately 75 psi

within two seconds, pressure is operating at its maximum

and is correct.

If fuel pump pressure does not rise to approximately

75 psi within two seconds, proceed as follows:

(11) Release fuel system pressure. Refer to the previous

Fuel Pressure Release Procedure in this group.

(12) Raise and support vehicle.

(13) Disconnect fuel supply line at inlet (fuel tank

side) of fuel filter. Connect Fuel Line Pressure Test

Adapter Tool number 6631 (3/8 in.) between fuel filter

and fuel supply line.

WARNING: THE FUEL SYSTEM PRESSURE IN THE

FOLLOWING TEST MAY EXCEED 100 PSI. BEFORE

STARTING TEST, VERIFY GOOD CONNECTIONS AT

ENDS OF ADAPTER TOOL 6631. BE SURE TOOL IS

LOCKED ONTO FUEL FILTER AND FUEL SUPPLY

LINE. PULL FIRMLY ON ENDS OF TOOL TO VERIFY.

(14) To activate the fuel pump and pressurize the

system, obtain the DRB scan tool. Refer to the appropriate

Powertrain Diagnostic Procedures service

manual for DRB operation.

MOMENTARILY pinch the rubber hose portion of

adapter tool 6631. Pressure should rise to approximately

75 psi within two (2) seconds. DO NOT pinch

hose for longer than three seconds.

If fuel pump pressure now rises to approximately

75 psi within two seconds, but this pressure could

not be met at the fuel rail, check for a plugged or restricted

fuel filter. Also check the fuel supply line between

fuel filter and fuel rail for kinks or

obstructions. Proceed to the following Fuel Pump Capacity

Test.

Not sure, but a guess would be 30 to 40 psi.

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