fuel pump problem or relay?

My '96 Grand Am GT is acting up lately. Every once in a while when I try to crank it, the fuel pump doesn't start up when I turn the ignition key. I was told that there should be a relay under the hood that sends a signal to the pump but I haven't found it. Does this sound like it is a relay problem or can the fuel pump also act this way? Every time the pump comes on like it's supposed to, the car cranks and runs perfect.

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'85 Toy

I guess I'll try replacing the relay since it only costs $14 and see if that solves the problem. If not it'll be the pump.

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'85 Toy

Make sure that it is the fuel pump first before throwing money away. You need to use a scan tool to see what the vehicle isn't doing when it won't start. The problem could be many different things. Throwing parts at the problem without diagnosis is a recipe for disaster.

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sparky

sparkie wrote:

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Make sure that it is the fuel pump first before throwing money away. You need to use a scan tool to see what the vehicle isn't doing when it won't start. The problem could be many different things. Throwing parts at the problem without diagnosis is a recipe for disaster.

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I agree you need to scan it. If It is the fual pump replace it with the factory oem replacment part. 1 time I had to drop the tank and change the pump  on a Caravan 4 times before it would last more than a week. After I put an oem in it  was fine.

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Big Dave

I see what both of you are saying. The only problem is when it won't start it's usually in my yard of the grocery store or Wal-Mart. I took it to a couple of shops and of course it would crank perfect every time. It only does this about one time in 50 tries or so. I had a couple of shops tell me they are pretty sure its the ignition switch, not the fuel pump or relay.

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'85 Toy

When it won't start did you check to see if you have spark?

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Big Dave

When it doesn't start try leaving the key off for a minute or so and get someone to listen to the underside of the car at the rear. Turn the ignition switch to on without cranking the motor and listen for a whirring noise that lasts a few seconds. This is the fuel pump pressurizing the line. It might help determine what the problem is. Relays aren't usually prone to fail on GM vehicles as they are weather packed. If the wiring to them is defective then you have a problem. You could also try tapping the relay when the probelm occurs to see if it helps.

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sparky

Maybe I'm not saying what is happening accurately enough. When I turn the key and hear the pump humming, it WILL crank. This is most of the time. It's when I turn the key and don't hear the pump that it just turns over and over and won't crank. That is what makes me think it is an electrical problem, not sending power to the pump every once in a while. They say it also has a security type piece of equipment that hooks to the ignition switch that can be going bad that will act this way too. The service manager at a local Pontiac dealership said that you have a lot of keys on the ring the extra "weight" will cause the sensor in this piece to eventually go bad. He suggested using just 1 key to crank it for a few days and see if the problem goes away, if so that will be the problem. It's a lot of things that it "could" be and until it leaves me stranded I guess I'll have to tinker around and try to figure it out. Speedway, yes it does have spark when it won't crank. Thanks for all the help so far to everybody.

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'85 Toy

I did try laying on my back and kicking under the tank, but it didn't seem to help. Then I thought about the pump being on top of the tank and figured it wouldn't help. Next time it happens I'll try it again with the rubber mallet!!!

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'85 Toy