Chevrolet Repair: 2002 chev cavalier fuel pump problem, cavalier fuel pump, fuel pump

Question
I am helping a friend on his 2002 cavalier that won't start. Read a past question for same problem and still stuck. Fuse is good. Lifted relay and metered voltage, good. Checked voltage at plug for fuel pump, black wire- grey wire+ ,12 volts. Connectors on fuel pump the same. Got a pump from the wreckers and plugged it in, still no go. Plugged it in to my 2000 cavalier and it works. Why do I have 12 volts, but no pump? I am stumped and any help would be appreciated.

Answer
Hi Bob... make sure you have a good ground....also check to make sure that the 12 volts still there when you plug in the pump...if not check the relay....check the plug for bad connection....most problems are ground related in the fuel circut when you have voltage....hope this helps