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I have searched the forums without any luck. I am pretty sure the fuel pump has gone out. Drive last week and she just
lost power. Stumbled and sputtered. Did manage for it to start and run enough to get me out of traffic. Tested at the fuel
rail and 0 pressure. Checked the relay and power is getting to the relay. Now I want to check the power at the pump. See
attached picture. What wires do I check for power at the pump? Any help greatly appreciated.
I don't know which pin exactly will be power. But if your fuse(s) are good and relay(s), and you get 0psi at the rail, pretty sure the pump(s) are bad. Not sure if you are NA or S/C, which I put the "(s)".
Checked the relay and power is getting to the relay. Now I want to check the power at the pump. What wires do I check for power at the pump?
The first test you can do is verify that the relay is operated by the ECM - listen to the relay (or keep your finger on it) while someone switches the ignition "on" (no cranking). If you hear (or feel) the relay clicks once and, after a couple of seconds, clicks again, the operation of the relay is fine. Then, check the fuel pump fuse (Fuse 7, 20A). If the relay clicks and the fuse is good, then check the operation of the pump (see attached diagram):
Prepare two short pieces of wire with male spade terminals at one end. As the fuel pump relay has permanent 12V coming to it, you don't need to switch the ignition "on" for the following tests.
1. Remove the relay, plug one wire into the socket for relay pin #3 (or #30 on some relays) and verify that there is 12V present (you can see the numbers next to the relay pins). For this test, it is better to use a 21W bulb, not a multimeter.
2. If the bulb lights bright at pin #3, plug the second wire into the socket for relay pin #5 (or #87 on some relays). See whether there is a spark when you touch the ends of the two wires together. If you get the spark, keep the two wires together and listen to the sound of the pump - you should be able to hear faint humming listening from the trunk or clearer sound listening at the opening of the fuel filler.
If you get no spark when touching the two wires together or hear no sound of the pump running, the pump is bad. You can also have a fuel pressure gauge connected during these tests to see if any pressure is being built-up.
Last edited by M. Stojanovic; 07-06-2020 at 11:02 PM.