DIY Network

Auto Fuel Delivery System -- Cleaning Fuel Injectors From "Weekend Mechanic" episode WKM-101

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Figure A Figure B Figure C Figure D Figure E Figure F Figure G

It was determined that the hesitation and stalling problems in the 1993 Taurus are likely due to the fuel delivery system. To verify the suspected fuel injectors as the cause of the problem, specialized diagnostic tests were used to rule out other factors such as the ignition system, sparkplug wires, fuel-system pressure and power supply to the injectors.

Our tests indicated that one injector is partially operational, and another is not operating at all. At about 5 hours into the project, this segment includes the cleaning and testing of fuel injectors in order to salvage them -- avoiding the price tag of $80 to $100 per injector that would come with replacing them. The cost of a fuel-injector cleaning kit is about $70.

Important: Included below are the steps in this automotive procedure 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.

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

Materials:

Fuel-injector cleaning kit
Extra-long screwdriver


Steps:

• The fuel-injection cleaning kit connects to the fuel port on the fuel rail -- where the fuel-pressure gauge was attached in the previous program segment. Before attaching the kit, it's necessary to unplug the pressure regulator (figure A). (Temporarily plug the vacuum hose onto any nearby stud.)
  
  
  
• It's also necessary to disconnect the fuel pump. On most newer cars, this can be accomplished by a sharp rap on the inertia switch, usually located in the trunk.
  
  
  
• Also, remove the fuel cap from the gas tank. Fuel-injector cleaning kits deliver a large amount of pressure to a fuel system very quickly. Removing the fuel cap will help ensure that excessive pressure does not build up in the system.
  
  
  
• With the cleaning kit hooked up (figure B), have an assistant turn the ignition to ensure that, with the fuel-pump shut off, the engine will not turn over.
  
  
  
• Open up the valve on the kit and check the gauge (figure C). Continue to open the valve until the fuel pressure reading matches the one appropriate for your vehicle. (This information is included in your vehicle's owners or service manual. For ours, the range is 35 to 45 PSI.)
  
  
  
• With the kit connected securely, and the appropriate reading on the gauge (figure D), the engine can now be started. The engine will run using the cleaning solvent as fuel during the cleaning. Allow the car to run until the solvent runs out and the engine shuts down. The engine will stop once the canister is empty. The process should take about 5 minutes.
  
  
  
• With the cleaning process complete, reset the fuel-pump switch in the trunk ( figure E), and replace the gas cap.
  
  
  
• Reconnect the pressure regulator (figure F).
  
  
  
• Now you can start the engine and check the fuel injectors for operation using an extra-long screwdriver as a "stethoscope" (figure G). Listen for clicking sounds in rapid sequence to indicate a properly operating injector.

  Note: See the previous segment for further information on this technique. There are actual mechanic's stethoscopes available, but the screwdriver technique is reliable as well.
  
  
  

• Safety Alert: Always use caution when working close to a running engine. Avoid contact with belts, moving parts, electrical contacts, etc.

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)