As far as the pump not running for 2 seconds when you first turn the key to the run position that isn't going to be a bad fuel pump because it operates like it should otherwise.I have never seen it not prime when turning the key to run and then work fine the rest of the time.I have only seen the pump not work at all or work like it supposed to. As far as checking back pressure that's easy they sell a back pressure gauge set for that you unscrew the o2 sensor screw in the adapter just like if you were checking your oil or transmission fluid pressure. Same kind of set up except your checking the exhaust pressure the gauge set's are pretty cheap.I have posted below how you test back pressure.
A slight pressure in the exhaust system is normal, but excessive exhaust back pressure seriously affects engine operation. Causes of high exhaust back pressure are dents or obstructions in the exhaust pipe, a plugged three way catalytic converter or muffler.
Test method (Vehicle Parked):
1. Remove the oxygen sensor.
2. Insert exhaust back pressure adaptor (SA9306E) into the exhaust manifold. The thread designation is M18 x 1.50.
3. Connect the gage bar kit SA9127E, 0 - 15 kPa gage (0 - 60 inch H2O) to the back pressure adaptor.
4. With the engine at normal operating temperature, observe the exhaust back pressure at 4000 rpm.
5. The exhaust back pressure must be less than 5.0 kPa (20.13 inch H2O). Test method (Performed During Road Test):
1. Remove the oxygen sensor.
2. Install exhaust back pressure adapter (SA9306E) into the exhaust manifold. The thread designation is M18 x 1.50.
NOTICE: Do not use the 0 - 60 inch H2O gage when performing this test, as it will be permanently damaged due to the high back pressure during accelerations. Use the 0 - 690 kPa (0 - 100 psi) gage and appropriate hoses in service gage bar kit SA9127E.
3. Connect the gage bar kit SA9127E, 0 - 861 kPa (0 - 100 psi) gage.
4. With the engine at normal operating temperature, perform a 15 mph road test. Automatic transaxles should be in "D" and manual transaxles in "3rd" gear. Maximum exhaust back pressure readings are taken during short wide open throttle accelerations.
5. The maximum exhaust back pressure during wide open throttle accelerations must be less than 50 kPa (7.25 psi).
IMPORTANT: If the exhaust pressure exceeds the specification, inspect for a dented or collapsed exhaust pipe. It may be necessary to disconnect the exhaust pipe before or behind the converter and repeat Step 4. If removing the muffler does not lower the back pressure, disconnect the resonator pipe from the down pipe and repeat the test.
6. Replace any part of the exhaust system found to be damaged.
7. Install anti-seize on the oxygen sensor's threads and install the sensor. It may be necessary to disconnect the negative battery terminal in order to clear any codes set while operating the engine with the oxygen sensor removed or disconnected.
Monday, March 21st, 2011 AT 1:27 AM