Dodge Omni/Horizon/Rampage 1978-1989 Repair Guide

Air Injection System

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OPERATION



This system's job is to reduce carbon monoxide and hydrocarbons to required levels. The system adds a controlled amount of air to exhaust gases, via an air pump and induction tubes, causing oxidation of the gases. The system is composed of an air pump, a combination diverter/pressure-relief valve, hoses, a check valve to protect the hoses from exhaust gas, and an injection tube.



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Fig. Fig. 1 The diverter valve prevents backfire in the exhaust system during deceleration


WARNING
The system is not noiseless. A certain squeal is present in pump operation.

SERVICE



For proper operation of the system, the drive belt should be in good condition and properly tensioned. The air pump is not a serviceable item; if necessary, it should be replaced.


WARNING
Do not attempt to disassemble the pump or clamp it in a vise.

Complaints of road surge at about 40-60 mph on 1978 Federal models equipped with manual transaxle and AIR pump can be corrected, in most cases, by installing a kit (Chrysler part No. 4131207). The kit consists of a vacuum bleed, an idle air bleed, a carburetor ID tag, main metering jet, air horn gasket and hose routing label.

REMOVAL & INSTALLATION



Air Pump
  1. Disconnect and tag the hoses from the pump.
  2.  
  3. Loosen the air pump idler pivot and adjusting bolts. Remove the drive belt.
  4.  
  5. Remove the air pump pulley and attaching bolts.
  6.  
  7. Remove the air pump.
  8.  
  9. Installation is the reverse of removal. Tension the drive belt, see .
  10.  

Diverter Valve

Servicing the diverter valve is limited to replacement. If the valve fails it will become extremely noisy. If air escapes from the silencer at idle speed, either the diverter valve or the relief valve has failed and the entire valve assembly should be replaced.

  1. Remove the air and vacuum hoses.
  2.  



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Fig. Fig. 2 Remove the hose leading to the air pump for better access to the diverter valve



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Fig. Fig. 3 Now disconnect the vacuum hose leading to the valve

  1. Remove the bolts securing the diverter valve to the mounting flange and remove the valve.
  2.  



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Fig. Fig. 4 Remove the bolts securing the diverter valve and remove the valve

  1. Remove the old gasket.
  2.  



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Fig. Fig. 5 Be sure to clean the gasket mating area well

  1. Installation is the reverse of removal. Use a new gasket and connect the hoses properly.
  2.  

Check Valve

The check valve is not repairable. If it is necessary to service it, replace it with a new one. The valve can be tested by removing the hose from the valve inlet tube. If exhaust gasses escape from the inlet tube the valve has failed. On California cars, if the tube nut joint is leaking, retighten the nut to 25-35 ft. lbs. (34-47 Nm). If the adapter to the exhaust manifold joint is leaking, retighten the connection to a maximum of 40 ft. lbs. (54 Nm). On Canadian cars, if the air injection tube to the head joint is leaking, retighten the hollow bolts to 20 ft. lbs. (27 Nm).

EXCEPT CANADA
  1. Release the clamp and disconnect the air hose from the check valve.
  2.  
  3. Remove the tube nut holding the injection tube to the exhaust manifold.
  4.  
  5. Remove the injection tube from the engine.
  6.  
  7. Installation is the reverse of removal.
  8.  

CANADA
  1. Release the clamp and remove the air hose from the check valve inlet.
  2.  
  3. On air conditioned cars, remove the air conditioning compressor from the mount.
  4.  


CAUTION
Do not disconnect any air conditioning system hoses.

  1. Remove the 4 isolated rubber compressor mounting bracket bolts and the compressor-to-cylinder head bolt. Set the compressor aside and keep it upright.
  2.  
  3. Drain the cooling system to a level below the thermostat housing.
  4.  
  5. Remove the housing from the bypass hose.
  6.  
  7. Remove the 4 hollow bolts holding the injection tube assembly to the cylinder head.
  8.  

To install:

  1. Install the injection tube assembly on the cylinder head. The 4 copper washers must be used between the tube assembly and the cylinder head.
  2.  
  3. Install the 4 hollow bolts with copper washers between each bolt and the injection tube assembly. The washers must be used. Tighten the bolts to 20 ft. lbs. (27 Nm).
  4.  
  5. Install the thermostat housing and connect the bypass hose.
  6.  
  7. On engines with air conditioning, reinstall the compressor. Adjust the drive belt.
  8.  
  9. Reconnect the air hose to the check valve inlet.
  10.  
  11. Refill the cooling system.
  12.  

 
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