How to Check a 1998 Blazer Fuel Pump
- 1). Raise the hood of the Blazer and visually locate the shiny metal tubing that runs along the top side of the engine. This tubing is called the fuel rail, which is responsible for feeding the fuel to the injectors. Locate the driver's side fuel rail, then the fuel pressure testing port on top of the fuel rail. Remove the cap that is identical to a tire valve stem cap, as this is the pressure testing port cap. Turn the cap counterclockwise to remove it, by hand.
- 2). Install a fuel pressure tester unit onto the fuel rail pressure testing port. Turn the pressure tester line until it is snug, unless the tester line has a quick connect fitting. Make sure you have a good hold on the fuel pressure tester port with the tester by pulling it back slightly to test the fitting.
- 3). Ask an assistant or second person to turn the engine on in the Blazer. If the engine will not turn on, ask your assistant to turn the engine over for no longer than three second intervals. Longer than three seconds will damage the starter and possibly engine components.
- 4). Read the dial on the pressure tester while the key is being turned, or while the engine is on. The dial gauge should be between 55 and 61 p.s.i., or pounds per square inch. If the dial does not reach this pressure during engine turn over or while the engine is running, then there is a problem in your fuel delivery system.
- 5). Ask your assistant to turn the Blazer off. Remove the pressure tester from the engine and replace the tester port cap immediately. Shut the hood on the Blazer, and work your way over to the fuel filler door.
- 6). Open the fuel filler door and remove the gas cap. Place your ear next to the fuel filler hole for the next series of tests. This audible testing will let you know if your fuel pump is indeed working or not.
- 7). Ask your assistant to turn the ignition key to the "Accessories" or "II" position, without turning on the engine. Tell them to turn the key to this position, then count to three and turn it back off. Your job during this cycle of testing is to listen for an audible electronic delivery noise. The fuel pump and sending unit will engage when the key turned. Listen for a high pitched motorized noise when the key is placed in "Accessories". If you do not hear a noise when the key is turned to accessories, then your fuel pump is not working properly.
- 8). Ask your assistant to turn the engine on for five seconds, and then turn it off. If the engine will not start, ask your assistant to turn the engine over for no longer than three second intervals. Your job during this step is to listen for an audible "gurgling" noise, or liquid movement in the fuel tank. If the fuel pump is working you will hear a "tinkling" or "gurgling" sound through the filler hole. If your engine will not turn over and you do not hear any noise from the fuel tank, then your fuel pump is not working correctly.
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