Fuel Filter: Testing and Inspection

Fuel Pump And Filter Mounting Bracket:

1. Check Fuel Filter for leaks, or damage to filter body. Remove Fuel Filter and check for restriction or blockage, for removal procedure refer to COMPONENT REPLACEMENT AND REPAIR PROCEDURES. Because of the varying quality of available gasoline, the Fuel Filter may become clogged enough during normal operation to restrict fuel flow. Periodic replacement of the Fuel Filter will help to prevent any such problems, and ensure continued good performance. Replace the Fuel Filter if it is flow restricted or if a defect is suspected. Refer to MAINTENANCE PROCEDURES.

Mini Fuel Filter:

2. Many Volkswagens equipped with CIS-E fuel injection have a mini fuel filter installed in the system to collect any contaminants which may have been trapped in the fuel system during manufacturing. The mini filter is a small mesh screen built into the union bolt that attaches the fuel supply line to the fuel distributor. The union bolt with the mini filter can be identified by a disc shape on the union head.
3. Removal of the mini filter is a one-time procedure. The old bolt/filter is replaced with a new union bolt without the mesh screen. This bolt/filter should be replaced if a fuel flow problem is suspected or when the fuel filter is replaced.