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HOMESERVICE MANUALSCHEVROLET1985IMPALA 4.3 Z, 700R4/MD8REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMFUEL INJECTION SYSTEM - DIESELTESTINGHPCA
1985 Chevrolet Impala 4.3 Z, 700R4/MD8

Fuel Injection System - Diesel: Testing: HPCA

1985 Chevrolet Impala 4.3 Z, 700R4/MD8SECTION HPCA
  1. When housing pressure is very low and adjusting the regulator See Adjusting the HPCA in this article, will not bring pressure to 9-11 psi (.6-.8 kg/cm2 ), the HPCA pressure regulator ball is either not seated or partially seated or clogged because of a fault in the pressure regulator solenoid.
  2. Remove the pressure regulator and attempt to blow air through it, pump side first, then outlet side. Replace if the check ball does not seat when blowing through the outlet side. If debris is found, check the injection pump.
  3. To check the solenoid, connect the electrical leads to the HPCA solenoid. Turn the ignition to "RUN". The solenoid plunger should be up. Turn ignition to "OFF". Plunger should fall by itself or with a very light push. If solenoid fails these tests, replace or repair.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.