Starting Problem (nothing like it on here)

[Sunspot]

2002 Grand Am SE with an 2.2 Ecotec motor.
Vehicle began to randomly not start and then for no reason one day will start and start for a week and then go back to not starting again.
When it originally didn't start, the fuel pump relay would just keep making a buzzing noise and the pump would not work.
Without touching anything, about an hour later I went back out and hit the key, the buzzing had stopped,I had fuel pressure, but the injectors were not powering up. I unplugged the injector harness and plugged it back in, the car then started (but I suspect this was coincidence)
So then the car started for a whole week without any problems (accept one theft no start, but that was always normal with this car)
On Staurday I went out and couldn't get the thing to start again, the fuel pump relay buzzed for a bit again but then stopped, no fuel pump again.
Tuesday I went out and the dumb thing started 5 times in a row, then didn't, then did, then didn't
As I write this, it is running great, but can't trust the car to take it anywhere.
I have a scan tool, no codes present
I am sure I missed some important info, so if you can help, but need to know more, let me know.
Please help, the car is worthless right now.
My gut says Computer

[mechanic1980]

id start with that buzzing relay its cheap way to start out then look at other options

[Sunspot]

Yes, relay has been tried and all new ones will buzz the same way. I believe this will be the key to the problem, but what would make the relay buzz? I see no ground wires, so relays must be grounded through the computer?, when the relay stops buzzing, then I will have fuel pump power, but no injector power. Pretty strange electrical issue? Fuel pressure PSI is between 47 and 48 when relay is not buzzing and also while the car is actually running. While relay is buzzing, there is no pump power, so therefore no fuel pressure. What would randomly do this?

[Sunspot]

come on guys, hasn't anyone had a buzzing fuel pump relay before? if anyone can help me out, I would greatly appreciate it.

[doctorhrdware]

I would check the wiring from the relay back to the PCM. Or it is possible that you have a problem with the ignition switch.

[3100]

next time when it doesn't start hit the gas tank with rubber mallet several times and try to start. Sounds like fuel pump going bad.

[doctorhrdware]

Originally Posted by 3100

next time when it doesn't start hit the gas tank with rubber mallet several times and try to start. Sounds like fuel pump going bad.

I am asking this because I don't know, could that cause the relay to buzz like that.

[3100]

relay can buzz from loose or bad contacts.

pcm controls fuel pump relay: blue connector at the pcm pin #46 is DRK GRN/WHT wire connect your voltage tester to see that the dark green with white wire from the pcm is giving 12v when someone is trying to start. See if you can find pin J7 at the relay that is from pcm control, on the other side of the relay coil is ground # 103 which is one of the main engine grounds located near the starter it is probably using 13 mm bolt. So clean the bolt with wire brush and make sure that the connection is tight. Check FP/Fuel injector fuse 15A. Then at the fuse block in left instrument panel you will see black and gray connectors connected with each other: on the gray side of that connector look for pin #b10 it should be gray wire, then on the black side of the connector look for pin#b3 it should also be gray wire coming from the fuel pump check that connector for looseness and clean contacts. Then check ground #302 which is for your fuel pump and is located under the front passenger seat. Clean that ground. Good luck

[Sunspot]

thanks for the info, I will let you know as soon as I chack all that out.

[mcmalloy]

check for a loose ground wire

[InUrDreamz]

Originally Posted by Sunspot

come on guys, hasn't anyone had a buzzing fuel pump relay before? if anyone can help me out, I would greatly appreciate it.

Your fuel pump shouldn't be buzzing. Sounds like a bad fuel pump. you will probably have to take it to a dealership, and they can test it. And then you can go from there. But if a dealership has to dismantle your gas tank, that can be expensive!

[Sunspot]

still checking out those other things

also, I believe the system is grounded through the computer, no external ground wires

and I didn't say the pump was buzzing....the relay was buzzing....pumps are supposed to buzz when they are working