Fuel Pump Delivery Volume To Pressure Regulator

Disconnect return line at diaphragm pressure regulator. Attach a hose to fitting on regulator and place other end of hose in measuring container.
For V8 engines, remove fuel pump relay (under hood near fuse panel). Bridge fuel pump relay connector pin sockets No. 7 and No. 8 with jumper wire to establish fuel pressure. See Figure .
For 4 and 6-cylinder engines, remove MAS unit from underhood component compartment area, near CIS-E control unit. To remove MAS unit, turn top knob from position No. 1 to position No. 0 and lift/pull MAS unit out of electrical connector socket. Using fused jumper wire, jumper connector pin socket No. 2 with battery voltage source to establish fuel pressure. Run fuel pump for only 40 seconds. See FUEL PUMP PERFORMANCE TABLE.
If delivery volume is lower than specifications, ensure pump is receiving minimum of 11.5 volts. Also check for dirty strainer in feed connection of fuel distributor to be causing restriction. Check for pinched fuel lines.
Pinch by-pass hose of fuel inlet at fuel accumulator and repeat delivery volume test. If volume is now correct, replace fuel accumulator. If volume is still low, replace fuel filter and repeat test. If volume remains low, replace fuel pump.
When testing is completed, reconnect fuel return line and tighten to 88-106 INCH lbs. (10-12 N.m). Install fuel pump relay or MAS unit. To install MAS unit, push MAS unit into electrical connector socket and turn top knob from position No. 0 to position No. 1.

FUEL PUMP PERFORMANCE

Application

Pressure psi (kg/cmFD)

⁽¹⁾ Volume Pts. (L)

4-Cylinder

⁽²⁾

6-Cylinder

77-80 (5.3-5.5)

2.1 ⁽¹⁾

88-91 (6.2-6.4)

2.1 ⁽¹⁾

⁽¹⁾	Minimum volume in 40 seconds.

⁽²⁾	Information not available from manufacturer.