97 Lumina 3.1 won't start

I read a few other "won't start" threads before posting this, my problem is a little different...

I have a 1997 Chevy Lumina 3.1 with about 104,000 miles. One day out of nowhere, the car wouldn't start. It would crank just fine and almost start, but wouldn't fire up. I had the car towed to a mechanic. They couldn't get to it until the next day and when they tried to start it, of course it fired right up. They ran a diagnostic test on it, but nothing showed. They kept it for two days and it fired up for them every time they tried. Finally, they said they couldn't diagnose the problem until it was malfunctioning while in their care, so I came and got it (they didn't charge me anything).

It drove fine for about a month and then when leaving work one day, again it wouldn't start. I called the mechanic the next day. (of course, after the car sat all night, it started up again) I gave him some details. He said it sounds like a bad fuel pump, but he didn't want to replace it unless he was sure, because its a bit of a pricey job. He said to have someone get under the car and bang on the gas tank while I was cranking it and if its the fuel pump, it should start up. Therefore, I had to wait until the next time it wouldn't start to try that tactic.

That was yesterday. I leave work and the car won't start. I have a co-worker crawl up under the car and bang on the gas tank while I crank it and nothing...today I come in to work (after the car has sat all night) and it STILL won't start. I called the mechanic back today and he said he still is not 100% sure its the fuel pump, and he's leaning toward the fuel pump RELAY. Well, we just got a new relay and put it in...still nothing. Car cranks but won't start.

WHAT could be the problem? Everything else is fine. All the lights on the dash work, the radio works, the battery is fine, I just replaced the alternator about 6 months ago so I know that isn't the problem.

Another co-worker suggested the fuel filter. I don't know...anyone??

Turn the key on, and have someone stand with their ear near the tank. Do they hear the pump buzz? IF not, try changing the relay first. if after changing the relay, you still don't hear the pump kick on, then you have a bad pump. If youdo hear the pump running when the key is turned on, then I would say you need to check for spark, as the crank sensor or ignition module could be shot.

Turns out it WAS the crankshaft sensor! Finally! Now I won't have to be worried about being stranded! THANKS!

I am having the same problem. Do you know which Crankshaft sensor they replaced. From what I am reading in my manual, it has two. I replaced one, but still having the problems.

Start a new thread here this is too old.