BMW Coupes and Sedans 1970-1988 Repair Guide

Cold Start Valve

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See Figure 1



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Fig. Fig. 1: Cut-away view of a cold start valve

The purpose of the cold start valve is to inject added fuel into the induction system as dictated by the temperature timing switch.

REMOVAL & INSTALLATION



  1. Remove the electrical connector and the fuel line to the valve.
  2.  
  3. Remove the retaining bolts and pull the valve assembly from the air collector.
  4.  
  5. Replace the rubber seal ring during installation.
  6.  

TESTING



See Figure 2



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Fig. Fig. 2: When testing a cold start valve, place the valve in a container to test whether fuel is being ejected

Remove the colt start valve from the induction header. Connect the relay terminal C87 to a positive battery connector. The cold start valve should eject fuel. If not, it should be replaced.


CAUTION
When testing the cold start valve, eject the fuel into a safe container as fuel is extremely hazardous.

REMOVAL & INSTALLATION



See Figure 3



Click image to see an enlarged view

Fig. Fig. 3: Cold start valve attached to the intake manifold of a 3 Series BMW

  1. Remove the nuts attaching the fuel lines leading to the injectors to the top of the distributor (1 through 4). Unscrew the union nut and disconnect the line leading to the warm-up regulator.
  2.  
  3. Disconnect the large low pressure fuel lines coming from the fuel filter going back to the tank, by removing the attaching bolts. Also disconnect the 2 high pressure lines from the side of the unit in a similar manner.
  4.  
  5. Remove the 3 screws from the unit. Then, lift the unit off the top of the mixture control.
  6.  
  7. Install in reverse order. Clean the control piston in a suitable solvent and replace it, if it is damaged. Use a new gasket where the distributor fits onto the top of the mixture control unit.
  8.  

 
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