Ford Full-Size Vans 1989-1996 Repair Guide

Catalytic Converter


The catalytic converter, mounted in the truck's exhaust system is a muffler-shaped device containing a ceramic honeycomb shaped material coated with aluminum and impregnated with catalytically active precious metals such as platinum, palladium and rhodium.

The catalyst's job is to reduce air pollutants by oxidizing hydrocarbons (HC) and carbon monoxide (CO). Catalysts containing palladium and rhodium also oxidize nitrous oxides (NOx).

On some trucks, the catalyst is also fed by the secondary air system, via a small supply tube in the side of the catalyst.

No maintenance is possible on the converter, other than keeping the heat shield clear of flammable debris, such as leaves and twigs.

Other than external damage, the only significant damage possible to a converter is through the use of leaded gasoline, or by way of a too rich fuel/air mixture. Both of these problems will ruin the converter through contamination of the catalyst and will eventually plug the converter causing loss of power and engine performance.

When this occurs, the catalyst must be replaced. For catalyst removal and installation, see the Exhaust System portion of Engine & Engine Overhaul .


Air Pump

See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: Typical air pump used on secondary injection systems

  1. Remove the drive belt.
  3. Disconnect the hoses from the pump.
  5. Loosen the pump retaining bolts and remove the pump from the engine compartment.
  7. Installation is the reverse of removal.