Fuel System - Chemical Cleaning Procedures: Overview
89audi05Applies To: ALL AUDI VEHICLES EQUIPPED WITH CIS, CIS-E AND CIS-E III FUEL INJECTION SYSTEMS
Subject: Fuel System Chemical Cleaning Procedures
(Supercedes Product Circular 88-04, Dated August 22,1988)
Number: Group:
89-04
25
March 31, 1989
Fuel System
This circular describes chemical removal of carbon, gum and varnish from the fuel distributor and fuel injector tips, which have resulted from fuel related deposits.
The vehicle examples used on the following pages represent an example of each TYPE of fuel system.
To achieve satisfactory results using this procedure, it is assumed that the engine otherwise meets specification, e.g. engine settings, compression, scheduled maintenance, etc.
Symptoms: Hard starting, long cranking and/or rough, uneven idle
Cause: Fuel injectors and/or fuel distributor gummed up, fuel injector tips clogged by varnish and carbon deposits
These types of driveability problems are frequently related to the use of gasoline with insufficient cleaning additives.
After performing this procedure, it may require regular use of fuel additives (i.e. Autobahn Gas Additive Part No. ZVW 246 003), or fuel containing these additives to maintain good engine performance.
Preliminary checks
^ test drive vehicle and determine engine performance
Check the following:
^ ignition timing
^ CO content (% of volume or mA or both)
^ HC content (ppm)
^ inspect for vacuum leaks
^ repair if found
^ inspect intake valves for carbon build-up
^ remove if necessary using carbon blasting procedures
The following procedures for fuel system cleaning are in no way connected to the GH Service Action. Refer to Audi Campaign Circular GH for information concerning the removal of carbon deposits from intake valves.