How to Test the Fuel Pressure on an Oldsmobile

by Leanne Clute
pressure meter image by Thor Jorgen Udvang from

Checking the fuel pressure in an Oldsmobile is part of the routine maintenance of a vehicle. If the pressure is too high it can cause poor gas mileage and black exhaust smoke, while if it is to low the engine may misfire. The fuel pump and pressure system work together to keep a car's engine running smooth. A check engine light, poor gas mileage and smoke are all indicators that you may need to test the fuel pressure.

Step 1

Consult the Oldsmobile car manual specific to the model of your vehicle to find the location of the fuel pressure test port. These often come with the vehicle when purchased, but if it is missing, one can be ordered directly from GM, the manufacturer of Oldsmobile.

Step 2

Attach the nozzle end of the fuel pressure gauge to the test port. If it does not fit properly you may need an adapter manufactured specifically for GM automobiles. It may be necessary to have one person hold the gauge while another runs the vehicle.

Step 3

Turn the ignition key to the "Accessory" setting and write down the gauge readings. This will be the starting reference number. The Oldsmobile car manual will have specifications listed for fuel pressure in the section of the manual that discusses fuel pressure tests.

Start the vehicle and allow it to run for five minutes. Record the pressure ratings again. Compare both readings to the specifications listed in the owners manual. If there is a large difference, the vehicle will need to be inspected for fuel filter or fuel pump repairs.


  • Have gas tank filled before testing fuel pressure. Cracks in the gas tank, loose gas caps and low fuel can all effect accurate pressure readings.
  • Check mileage at each fill up. A sudden change in gas mileage is a clear indicator that there is an issue with your Oldsmobile. Regularly checking the mileage will help automobile owners detect problems early on.
  • If you are unable to find an owners manual for your vehicle through the manufacturer then try online auction websites and swap meets or garage sales. Many libraries and auto repair shops have manuals on hand that can be borrowed.


  • Always have a vehicle checked out by a certified mechanic if you believe there is an issue. Low fuel pressure can be caused by something as simple as a loose gas cap and as complex as a bad fuel pump. Second opinions from professionals will save unnecessary dollars in repairs.
  • Keep flames away from the vehicle while checking fuel pressure. Gasoline is highly flammable and even a cigarette ash can cause it to ignite and potentially destroy a vehicle. Clean all areas around the car after testing fuel pressure to alleviate future accidental fires.

Items you will need

  • Oldsmobile car manual
  • Fuel pressure gauge
  • GM adapters
  • Pen/pencil
  • Paper

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