🪩 When A Fuel Pump Relay Is Bad

wellyou could have a friend cycle the key a few times while you poke your head under the truck. you should hear the pump whining. also you can hook up a pressure guage to your fuel rail after cycling the key a few times you should have pressure. i have done this job on my other expedition and its pretty straight forward should only take a few hours at most. also if you pull the electrical Thejuice for the fuel pump actually comes from the ign switch to the ASD relay and then to the fuel pump relay. The PCM indirectly grounds the fuel pump by grounding the two relays (ASD & fuel pump relays) which sent power to the fuel pump. Measuring for 12v down at the fuel pump harness would cut to the case; as Joe has suggested. Ifthe ASD relay does not activate, the fuel pump relay will not activate. The crank sensor can be accurately test with just a multimeter: How To Test The Crank Sensor (1994-1996 3.9L, 5.2L, A bad fuel pump but not always (there are no absolute truths in life but death and taxes). Thefuel pressure test gauge should show 56-62 PSI and the engine should start if the previous relay was defective. Let's take a look at what your test results mean: CASE 1: The fuel pressure test gauge recorded 56-62 PSI after swapping the relay. This test result confirms that the fuel pump relay is defective and needs to be replaced. POreplaced the fuel pressure regulator twice (first replacement claimed to be defective) a little over a year ago, so must have been a persistent problem. I am thinking an 11 YO car with only 30K miles must have been sitting at some point creating a shellac problem? Defective fuel pump relay; Bad fuel rail sensor; Defective fuel pump; Home Inthis Video I explain and show how to test for a non-functional fuel pump circuit on a MEFI Marine gasoline engine commonly found on marine inboard and Ste Thefuel pressure should be 3.7: 4.2 bar with the engine running or when cranking. Once you test the pressure, recharge the fuel system by cycling the key or running the fuel pump. Note the fuel pressure. Then allow the fuel system to sit under pressure for 30 minutes. It should hold a minimum of 2.5 bar. Whenyou put jumper between Fp and B+, you bypassed the fuel pump relay, so even if the circuit opening relay is bad the pump should work. If it does not, use 12 volt cordless drill (such as DeWalt or equivalent, 9 volt will work as well) for the further testing: 1. Remove battery pack from the drill and identify polarity on its connections (using cheap analog voltmeter) 2. 8 Loud whining noise. A damaged fuel pump might make a loud, whining sound that you'll hear from your gas tank. The pump may also make this noise if you're low on fuel or the fuel in your tank is contaminated. If you hear whining while on a run, the noise could be coming from your fuel pump. AOZrA1y.

when a fuel pump relay is bad