Residual fuel delivery adjusting screw
WARNING: This page is about a different car, the 1996 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.
The residual fuel delivery adjusting screw -5- is secured with an anti-tampering cap and its setting must not normally be altered. See Fig 1 .
The so-called residual fuel delivery is adjusted on a test bench by the manufacturer, using this screw.
If the screw setting has been altered, this may result in the following problems:
- Screw turned in = residual fuel delivery too large. In this case, engine speed increases and it is not possible to set idle speed.
- Screw turned out (idle travel to control lever) = residual fuel delivery too small. This causes performance problems such as a "flat spot" when starting from rest and accelerating from low revs, or jerking in all gears.
If such problems occur, the following basic setting must be carried out at the residual fuel delivery adjusting screw -5-.
- Remove anti-tampering cap.
- Release lock nut for adjusting screw -5-. See Fig 1 .
Residual fuel delivery too small: (performance faults):
- Turn adjusting screw in just until idle speed increases.
- Turn adjusting screw back one-half turn from point at which idle speed increases.
- Lock adjusting screw and secure with new anti - tampering cap.
Residual fuel delivery too large: (engine speed too high):
- Turn adjusting screw out until engine speed no longer drops.
- Turn adjusting screw in again until idle speed rises.
- Turn adjusting screw back one -half turn from point at which idle speed increases.
- Lock adjusting screw and secure with new anti - tampering cap.