Electric issue in fuel pump circuit!

[Djsnyder16]

Hey guys, this is my first post on here and I've been using this site for help my entire way through this project but at this point I'm not even sure what to search on here because I'm so lost. I'm working on my girlfriends car ever since it died on her because of a bad alternator. It has always had a rough idle. I replaced the alternator no problem (thanks to a thread on here) and then when I went to start it I could keep it running I found it to be low fuel pressure. I check all the fuses and relays and everything was working. I went to the fuel pump and took it out and tested it by jumping it. It works perfectly fine. Then I checked the power at the connector for the fuel pump and I only have power to my fluid level sensor, not the pump. Then I went back to check the fuse and relays and I have no connection at the fuses under the hood! I have no idea what is going on or where to even go from here. Any ideas? Thanks for the help!

[Timm]

The fuel pump only gets power for a short burst when the ignition is switched ON initially, and then will do nothing until the engine is turning (either running or cranking) - so don't worry if you can't find power on the pump without the engine running.

[Djsnyder16]

Even when cranking the engine, I have no power at the pump

[Mayorchuck]

DME sends power to the relay, in the trunk, while engine is cranking IF it's getting the needed signal from the crank position sensor. That particular sensor does not always throw a code when it's bad. If you have a VOM, check the ohms. Should be around 550 between pins 1 and 2. If will be way off or zero is it's bad. Bosch only if you have to replace it.

[carnut1947]

I don't know the proximity of the crank sensor to the alternator mounting, but replacing it maybe unplugged it?

[Mayorchuck]

B6203, X6203


on RH side of transmission

B6203	Crankshaft position/RPM sensor
X6203	Component connector (3 -pin, Black), Crankshaft position/RPM sensor