DIY Network

Fuel System Service and Fuel-Injector Replacement From "Weekend Mechanic" episode WKM-101

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Figure A Figure B Figure C Figure D Figure E Figure F Figure G Figure H Figure I Figure J Figure K Figure L Figure M Figure N

With the fuel-injector cleaning complete, and the auto's performance problems (hesitation and stalling) reliably diagnosed as a bad fuel injector, the repair of the fuel-delivery system can get underway.

At this point in the weekend-long project, the electrical system was ruled out as a problem, the fuel-delivery to the injectors has been checked and the fuel injectors have been cleaned. One of the injectors is still not working at all, so the repair will be to replace the bad injector. At the same time, some related preventive maintenance on the fuel system will be performed.

Important: Included below are the steps in this automotive repair as shown in the episode. These steps are general guidelines that are applicable to most vehicles. With any particular vehicle, there may be procedures, specifications, settings, tolerances, components, etc. that are specific to that vehicle. Always consult your vehicle's service manual when undertaking significant automotive repairs.

Materials:

Replacement fuel injector
Replacement PCV valve
Replacement intake gasket
Replacement fuel-injector O-rings
Flat screwdriver
Automotive wrenches


Important : Check your vehicle's service manual for the proper part number for the replacement injector and any other replacement parts.


Safety Alert: Fuel-related projects require a well-ventilated work area.


Steps:

• To remove the bad fuel injector and install a new one, it's necessary to access the fuel rail where the injectors are attached. On the 1993 Taurus, some of the air intake assembly first had to be removed, the PCV valve removed (figure A), and the upper intake manifold lifted out (figure B).
  
  
  
• With those components out of the way, the fuel rail can be pulled from the engine (figure C).
  
  
  
• The bad injector was identified in earlier segments. With the fuel rail off, the bad injector can be removed. Remove the retaining clip using a flat screwdriver, and remove the injector (figure D).
  
  
  
• Examine the new injector carefully. It should have an O-ring on the top and on the bottom. Make certain the O-rings are present, otherwise a gas leak will result.
  
  
  
• Install the new injector where the old one was removed (figure E) and secure it with the retaining clip. Make certain that the injector is lined up properly.

  Important: Once the injector is installed, give it a slight tug to ensure that the connection is secure. A loose connection will result in a gas leak.
  
  
  

• As preventive maintenance, all of the injectors (figure F) were visually inspected and new bottom O-rings were replaced on all of the other injectors (figure G). Re-installing the injectors with old, worn O-rings might result in a vacuum leak -- leading to a separate problem from the one just repaired. When replacing the O-rings, first wipe any debris from the tip of the injectors to ensure that no contaminants get into the fuel system. To avoid damage to the O-rings, lubricate them with motor oil before re-installing the fuel rail.
  
  
  
• With the O-rings replaced and lubricated, position and re-install the fuel rail (figure H), making certain that all of the injectors line up with their corresponding holes on the ring.
  
  
  
• With the injectors all lined up, press down firmly to seat everything in place (figure I).
  
  
  
• Since the upper intake manifold was removed, it can be cleaned and serviced before reinstallation. Begin by cleaning the manifold surface that contacts the gasket ( figure J). Since the manifold is aluminum, clean it gently to avoid scratching or gouging the surface. The gasket was replaced as well.
  
  
  
• Earlier it was discovered that the nuts on the intake were loose. These can be tightened (figure K) before the intake is reinstalled. Loose manifold bolts can cause a vacuum leak and poor performance.
  
  
  
• Since earlier the PCV (positive crank ventilation) valve was found to be worn, it was replaced with a new one.
  
  
  
• Pieces of paper wadding were placed in the intake to prevent debris from falling into the engine during the removal of the gasket. These are now removed (figure L).
  
  
  
• Install the gasket (figure M) without using any sealer.
  
  
  
• Finally, replace the upper intake manifold and tighten the retaining bolts (figure N) to the proper torque specifications.

RESOURCES :

The Complete Idiot's Guide to Trouble-Free Car Care
Author: Dan Ramsey
ISBN: 0028635833
Alpha Books

Auto Repair for Dummies
Author: Deanna Sclar
ISBN: 0764550896

Fuel Injection: Installation, Performance Tuning, Modification
Model: 0879387432
Author: Jeff Hartman
Motorbooks International (MBI Publishing)