Q: How to Inspect, Clean and Replace Fuel Injector,Fuel Pressure Regulator,Idle Control Valve and Throttle Position Sensor on Chevrolet Metro?
A: All the TBI parts and subassemblies with the exception of the AC valve, and pressure regulator diaphragm, and any rubber pieces, should be cleaned in a cold immersion Cleaner such as Carbon X or the appropriate equal. To check the fuel injector remove the air filter housing connected to the carburetor or throttle body to check the fuel injector, crank the engine then look at the fuel spray pattern it should be even conical if not then replace the fuel injector. Once the engine is switched off, a normal check is to look at the injector and no dripping more than one drop per minute is allowed. Remove the electrical connector of the injector, depressurize the fuel system, remove the negative terminal of the battery, and of course remove the fuel feed line on the throttle body. The injector cover screws must be unscrewed, the injector electrical connector disconnected then compressed air must be used to help in the withdrawal of the injector while collecting any fuel which may come out with a rag. Check the fuel filters, sanitize them for dirt if found to be dirty. Light oil should be used to lubricate the O-rings, and the injector should be fitted tightly into its bore and a secure injector cover placed on top of it. Bolt the battery connection back, pump fuel system and search for signs of fuel leakage. In the case of the fuel pressure regulator the battery cable should be detached and the fuel system depressurized before the regulator is unscrewed from the throttle body. Check on any damages on the diaphragm and that the spring is properly fixed before putting a new regulator in place. Reconnect the fuel return line and battery cable and than pressurize the fuel system again and look for leakage. On the throttle switch of the automatic transaxle models, the electrical connector must be disconnected and a feeler gauge inserted to check for continuity as well as adjustment if the continuity fails. As with the older cars, refer to the automatic transaxle models and then remove the battery cable, electrical connector, and conductivity test between the terminals with the throttle fully open and closed, before proceeding to adjustment or replacement of this sensor. To test the air valve, the valve should be opened when the engine is cold and should close if the engine is warm; if not, the air valve must be replaced. Last of all, fine-tune the idle with the engine at normal temperature, air-cond on and the RPM must be within the required range of RPM for the respective transaxle.