The GRAY wire you mentioned goes to the fuel pump. The other end of that wire goes to the fuel pump relay, which is locaed in the underhood fuse block. The relay gets it's power from the FUEL PUMP fuse (15A); also in the underhood fuse block.
Generally, this wire will have power on it for only about 2 seconds when the key is turned on and the engine is not cranked (spinning over). Then a timer cuts the power off. If the engine is being cranked the power continues when the engine starts to run.
Use a test light to check for power on the gray wire when the key is switched on (do not spin engine over). Light should come on for about 2 secs and then turn off. Also, check the black wire in the fuel pump wiring harness. It's a ground wire; make sure it is getting a good ground.
By the way, don't bypass the computer! Could cause other problems or even short out relays, blow fuses, damage computer, etc.
The gray wire goes to the relay terminal B5. You may have to backprobe this terminal to see if it has power when the key is first turned on.
If this wire is burned, it could indicate a short in the wire. Check the wire at several places along it's length to see where it has power(remember it only has power for 2 secs when key is on, so you'll have to turn the key on and off several times during the tests). If it has power at a point closer to the relay but none at a point further from the relay, then the short is between those two points.
Saturday, July 17th, 2010 AT 9:20 PM