Hey guys so I had a problem with my car over a month ago. Below is my post for the original problem.
So yesterday I was driving my car for awhile and me and my girlfriend were going to the mountains that day. So I had just under a half tank of gas so I decided to stop and fill up, with 93 of course. I reset my trip at the gas station as I always do when a fill up. So we get to the mountains, and we are stopping to take pictures here and there. And I am in the habit of turning the car ON to let the fuel pump kick on and cycle. This time though the fuel pump whines louder than I had ever heard it before. Almost a squeal. So I started it anyways because we were on a one way road scenic tourist loop. I notice as we are driving through, no more than 15-20mph, that the pump is a little louder than usual. Sure as hell a little ways down the road it got louder and then I hear it shut off and the car dies. I let it cool for an hour assuming it just overheated, It runs for five minutes, and dies again. This happened only ~36mi after getting the full tank of gas. After a long day yesterday I got the car home last night on the bed of a tow truck and started to check it out this afternoon. Assuming I got bad gas perhaps, I put in two bottles of gas treatment and let it sit for 45 minutes or so. I then let it run for 45 minutes, occasionally driving up and down the street. It wont make the noise any more, idles fine, and it wont stall out. The pump that is in it is comparable to a Walbro 255 or it is one. I cant remember sorry. The pump and filter have less than 10k miles on them so I see no reason they should fail already. I never run my tank low. What could it be? What should I do? Should I be cautious about driving the car? Thanks guys!

Now yesterday it was about 95 out and we were in stop and go traffic, hotter than hell out, and the car did it again only this time the fuel pump just started to sort of cut out for a minute then it just shut off. Started the car up a couple minutes later and I went to try and drive it and it never made it to second gear before it shut off again. I switched the key to on and the fuel pump did not turn on. 5 minutes later while I am waiting for the tow truck I turn the key to on and the fuel pump comes on and it sounds normal. What the hell is wrong with my car? There is a half tank of gas in it but could it still be the fuel pump is overheating? Could the fuel pump relay be bad? Or overheat? PLEASE HELP!

 

Try a different tank of fuel. Sounds like it may be a vapor lock problem, due to high fuel temperature. Could be "flashing" to vapor in the fuel pump inlet.

 

Guess I never thought about that. Do you know of an easy way to drain the tank? Would disconnecting the line and cycling the key on and off be the easiest way?

 

I opened the gas cap and a TON of pressure came out. I let it run for about 15 minutes, mostly idling some driving, shut it off, and took the gas cap off, and it released even more pressure. I put a locking gas cap on quite awhile ago, but arent these caps supposed to vent? Could it be a bad gas cap?

 

cycling the key will kill you ignition. There is a jump cable off the pcm to cycle the fuel pump. simply connect it to your 12v battery wire and it will pump out everything.

 

Ok. Isn't vapor lock something that was common among carbureted engines? I didnt think it was something that could happen to fuel injected motors. Is there a chance that the fuel pump relay could be bad? Or the relay is overheating? I've heard of people having problems with the connector going to the relay. Any truth to that? Thanks guys!

 

The 4th Gens use a NON-VENTED gas cap, so that is not the problem. The fuel tank vents through the charcoal canister in the driver's rear fender. There is a pressure control valve between the fuel tank and the canister that releases some of the pressure in the tank, if the fuel is extremely hot, or the fuel is not blended correctly, and has the wrong Reid vapor pressure. Has your fuel pump been acting up at all? A failing pump can put heat into the fuel.

High pressure in the tank may mean the pressure control system described above is not working. Or, it may be a problem with the fuel getting hot, and driving off a lot of vapor that needs to be vented. But that pressure would offset the tendancy of the fuel to vaporize in the pump inlet.

Carb'd cars have problems with vapor lock in the line from the tank to the mechanical fuel pump on the side of the engine. The length of the line causes pressure to drop, and as pressure drops, the fuel will start to vaporize. Generally, its not a problem with fuel injected engines, because the pump is submerged in the tank, and the line from the pump to the tank is under high pressure. But you can still get fuel flashing to vapor in the pump inlet.

You don't have to drain the fuel... just add new fuel as you use up the old fuel. If you want to remove the old fuel, use a siphon hose in the fill pipe. I know it can be done.

 

Actually it has. Somewhat. The other day when it stalled the fuel pump just cut out and it stalled. So I let it sit for two minutes or so and the fuel pump sounded normal but when I went to drive it, the car stalled before it ever even got in second gear. As soon as it stalled I turned the key back to the on position and the fuel pump didnt turn on. As I was waiting for the tow truck to come, I waited for five minutes and turned the car back to the on position and the fuel pump kicked on and sounded normal. So yesterday switched the fuel pump relay and I went out and ran the car for about a half hour. Idling, drive easy, drive it hard, stop and go, some highway. And then shut the car off. The fuel pump sounded louder to me than it did when I started it. So out of curiosity I switched the key back to the on position and the pump was LOUD. Almost a squeeling sound. But today I drove the car to work so that we can tear into it this week and it drove just fine, started up nice, and fuel pump sounded normal. This fuel pump has less than 8k miles on it. Now I know this doesnt mean much because you can buy a brand new fuel pump and it doesnt work. Im thinking I need a fuel pump. Im trying to sell the car right now and this is a huge set back. I need a Walbro 255, anyone used the Granatelli pump? It's inexpensive and thats what I need right now. Thanks Fred!

 

When you hear the f/p being loud, open the cap and see if there is a lot of pressure in the tank. Could be one of the EVAP components is letting the pressure build up.

I had a situation like that in my 97 Grand Prix when I was on a long trip. The issue went away on it's own, though, so I never knew what really was the cause.

 

Fuel pump got a little loud today. Opened the cap while running still and LOTS of pressure came out. Now what? lol. Could it be a plugged up fuel filter? And the pump is having to work harder because of it?

 

That might be a possibility. Change it anyway.