Injection Pump Housing Fuel Pressure
- Engine must be at normal operating temperature. Remove air crossover assembly and install screen covers over openings in intake manifold.
- Remove pressure tap plug or Metering Valve Sensor (Calif.). Connect a low pressure fuel gauge to injection pump. Install magnetic pick-up tachometer.
- Start engine and run at 1000 RPM with transmission selector in "P" or "N". Pressure should be 9-11 psi (.63-.77 kg/cm2 ), with no more than 1 psi (.07 kg/cm2 ) fluctuation.
- If pressure is zero, remove connector from HPCA terminal. If pressure is still zero, remove injection pump cover and inspect solenoid operation. Free up solenoid if binding.
- If pressure became normal when solenoid lead was disconnected, check operation of EGR-TVS or temperature switch (Calif). If pressure is still low, replace or clean fuel return line connector assembly and return line.
- If pressure is too high, check fuel return system or HPAA for restrictions. Remove return line at the injection pump.
- Install a fitting and short piece of hose to allow the return flow to empty into small container. If fuel return line connector assembly is replaced, reset injection timing. See ADJUSTMENTS in this article.
- Recheck pressure. If pressure is still not correct, remove injection pump for repair. Pump is not serviceable and must be exchanged for another unit. See INJECTION PUMP R & I in this article.
- Remove tachometer, pressure gauge and adapter. Install a NEW pressure tap plug seal on plug. Install tap plug or torque screw into pump.
- On California vehicles, install the MVS using a new "O" ring. Coat threads with Loctite 242 or equivalent. Tighten MVS to 30 INCH Lbs. (3.5 N.m) Check and adjust if necessary the MVS voltage output.
- Remove screened covers from manifold. Install air crossover assembly.