Genuine 1989 Pontiac Firebird Fuel Pump

1989 Pontiac Firebird Parts Questions & Experts Answers

• Q: How to test the fuel pump and check fuel pressure in fuel injected engine on 1989 Pontiac Firebird?

  A: When diagnosing fuel pump check the fuse for fuel pump and if it is blown then replace it. Pull the PLASTIC COVER of the Assembly Line Diagnostic Link (ALDL) which is placed under the instrument panel, to the left from the console and apply battery voltage to terminal G to energize the fuel pump If the pump or relay inside the fuel tank is dead, then, you will have to check for the loose connection or an open circuit or an faulty fuel pump. If the pump runs, check fuel pressure with the air cleaner removed and plugging the Thermac intake vacuum port on TBI unit. Turn the ignition off, while opening the fuel cap, then read the fuel pressure with a gauge, before disconnecting the fuel line between the front and rear throttle bodies with a back up wrench so that the fuel nut won't turn. Take a fuel injection pressure gauge, connect two short rubber hose sections with the T-fitting and put it between two TBI balance line fitting; this should measure between 9 and 13 psi. Start the engine and check the fuel pressure; it should be in the prescribed limit. If there is no pressure despite of that the pump is functioning well, this may be caused by a clogged inline fuel filter, which has to be replaced. If pressure is less than 9 psi check fuel rail and line fittings and injectors for any major restrictions or leaks. If pressure is above 13 psi, examine troubles which are the fuel return line and the fuel meter cover. After confirming the fuel pressure put the steel fuel line and air cleaner back into its place. For the fuel flow check of MPFI and TPI immobilize the fuel pump, disconnect the fuel feeding line from the fuel rail and let the flow into a proper receptacle. In choosing the pump-that is move water at the required rate-the pump should deliver not less than 1/2 pint/a period of 15 seconds; if less do not proceed unless restrictions are present. For fuel pressure check simply connect a fuel pressure gauge to the fuel pressure fitting located on the fuel rail, turn the ignition on and should see the pressure between 34-47 psi. If pressure is normal in accordance with specifications put on the power and check if it is 3 to 10 psi less than earlier recorded pressure. If the pressure is less then which is specified, check the fuel quantity, filter and the lines for the problem; if there is none, replaces the fuel pump. In the circumstance where the pressure is high outside the specification, inspect the fuel return line and pressure regulator for replacement if required.