LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Plymouth >> 1987 >> Horizon Automatic >> Repair and Diagnosis >> Engine Performance >> System >> EFC System >> System Testing >> Electronic Fuel Control - System Tests >> Preliminary Fuel Tests
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Preliminary Fuel Tests

  1. Connect fuel pump pressure tester to fuel line at carburetor. Crank engine for 10 seconds. Fuel pump pressure should be 1-4 psi. If pressure is okay, check carburetor inlet circuit and repair as necessary.
  2. If pressure was not to specifications, connect fuel pressure tester to fuel line before fuel filter. Crank engine for 5 seconds. Fuel pressure should be 1-4 psi. If pressure is now okay, replace fuel filter.
  3. If pressure is still not to specifications, connect a vacuum gauge to the fuel pump inlet line. Disconnect the outlet fuel line from the fuel pump. Crank engine for 10 seconds. Vacuum gauge should read at least 10 in. Hg. If vacuum is okay, check for restricted fuel lines, improper fuel tank venting, and defective tank filter. If vacuum is not to specifications, replace fuel pump.
scientia non olet · About LEMON Manuals