GM Metro/Sprint 1985-1993 Repair Guide

Fuel Injectors

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REMOVAL & INSTALLATION



See Figures 1 and 2



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Fig. Fig. 1: Removing injectors from fuel rail



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Fig. Fig. 2: Make sure injectors rotate freely in cylinder head

  1. Relieve fuel system pressure and disconnect the negative battery cable.
  2.  
  3. Remove intake air hose between throttle body and intercooler.
  4.  
  5. Remove accelerator cable.
  6.  
  7. Unclamp PCV and fuel return hoses from deliver pipe.
  8.  
  9. Unclamp injector wiring harness.
  10.  
  11. Disconnect injector coupler.
  12.  
  13. Remove cold start injector pipe from delivery pipe.
  14.  
  15. Remove vacuum hose from pressure regulator.
  16.  
  17. Remove fuel feed hose from delivery pipe.
  18.  
  19. Remove pressure regulator from delivery pipe.
  20.  
  21. Remove delivery pipe with injectors.
  22.  
  23. Remove injectors from delivery pipe.
  24.  

To install:
  1. Replace injector O-rings and lubricate with fuel.
  2.  

Make sure injectors rotate smoothly. If not, probable cause is incorrect installation of O-ring.

  1. Check if insulator is scored or damaged. If it is, replace with new one.
  2.  
  3. Connect delivery pipe with injectors.
  4.  
  5. Install pressure regulator to delivery pipe using a new O-ring.
  6.  
  7. Install fuel feed hose to delivery pipe.
  8.  
  9. Install vacuum and fuel return hoses to pressure regulator and clamp securely.
  10.  
  11. Install cold start injector pipe to delivery pipe using new gaskets.
  12.  
  13. Install injector coupler. Clamp injector wiring harness.
  14.  
  15. Install PCV hose to cylinder head.
  16.  
  17. Install throttle position sensor coupler.
  18.  
  19. Install accelerator cable and adjust free-play.
  20.  
  21. Install intake air hose to throttle body and intercooler.
  22.  
  23. Connect the negative battery cable.
  24.  
  25. Start engine and check for leaks.
  26.  

TESTING



See Figures 3 and 4



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Fig. Fig. 3: Measuring injector resistance

  1. Using a sound scope, check if injector make proper operating sounds in proportion to engine speed when engine is running or being cranked.
  2.  
  3. If check result is not satisfactory, it means that defect exists in injector, wiring harness, connector or ECM.
  4.  
  5. Remove coupler of injector and check resistance between terminals. Resistance should be 13.8 ohms at 68°F (20°C).
  6.  
  7. Perform injector balance test.
  8.  



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Fig. Fig. 4: Injector Balance Test

 
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