Attention! Gasoline is highly flammable. Therefore, additional precautions must be taken when working on any part of the fuel system. See warning in paragraph 2.
1. Check all electrical connections of the system, especially ground connections. Loose connectors and poor ground connections can cause many problems with the engine management system.
2. Make sure the battery is fully charged because the powertrain control module (RSM) and sensors cannot work properly without receiving sufficient supply voltage.
3. Refer to chapter 1 and check the air filter element. Dirty or partially clogged filters impair driving performance and increase fuel consumption.
4. Check the operation of the fuel pump (see paragraph 3). If the fuel pump fuse is blown, replace it and see if it blows again. If it burns out, locate the short circuit in the wiring harness to the fuel pump.
5. Inspect the vacuum hoses connected to the intake manifold for damage, deterioration, and leaks.
6. Remove the intake air line from the throttle body and check for dirt, carbon deposits or other deposits in the throttle body, especially around the throttle body. If dirt is present, refer to chapter 6 and diagnose the positive crankcase breather systems (PCV) and exhaust gas recirculation (EGR) in order to identify the cause of the increased amount of deposits.
7. With the engine running, apply a car stethoscope to each injector in turn and listen for a clicking sound that accompanies the operation of the injector (pic. 12.7). In the absence of a stethoscope, you can put the tip of a long screwdriver to the nozzle and listen through its handle.
Pic. 12.7. Using a stethoscope, listen to each fuel injector and check for a clicking sound when the engine is running
8. If the nozzle does not seem to be working (does not click), purchase a special injector test indicator light and connect it to the electrical connector in the injector harness (pic. 12.8). Start the engine and see if the lamp flashes. If blinking, the injector is receiving the correct voltage. If not flashing, additional diagnostics are required. You should contact the dealer's technical service department or other qualified personnel.
Pic. 12.8. Connect an indicator light to the electrical connector of each fuel injector and check that it flashes when the engine is running
9. With the engine off and the electrical connectors of the injectors disconnected, measure the resistance of each injector with an ohmmeter (pic. 12.9). For information on the correct resistance, refer to Specifications at the beginning of this chapter.
Pic. 12.9. Set the mode control on the digital multimeter to the appropriate resistance range, touch the probes of the device to the two contacts on each injector and measure the resistance, which should be in the range indicated in Specifications at the beginning of this chapter
10. To test other systems, refer to chapter 6.