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I have Pontiac Grand Am 2004. It's been needing some regular maintenance, but other than that runs mostly fine. When I went out to start it this morning, it started fine. I went to start brushing snow off of it, and then (about 30 seconds after starting), it sputtered and died. I thought it was probably nothing, so I started it again. This time stayed alive for about 15 seconds. And each time I tried to start it afterwards, it would run for less time. Now, it won't start.

The way it would die is it would just lose RPMs, down to 500, until I would kill it. I tried pressing on the throttle after it started to lose RPMs, but nothing happened. However, immediately after starting the car the third time, I pressed on the throttle and it responded fine. A few seconds later though, it started to die and the throttle didn't have any response

I got gas two days ago, It had no problems starting yesterday morning, sitting at about a quarter tank. It was especially cold last night, but my car has sat for three days before, through very cold weather, and started fine when I needed it.

I tend to think ice in the fuel line, but then why didn't it fail yesterday?

Is there anything I can do to diagnose this further before having to be towed to a garage?

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4 Answers 4

up vote 2 down vote accepted

I'm not a mechanic and have minimal knowledge with cars, so I had it towed to a garage. The mechanic there said it was a bad fuel pump. It's a rather expensive replacement with parts running about $250, and labor costing about $250 (they have to remove the gas tank and everything)

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The fuel pump comes on when the key is turned to accessory. You could test that by removing the hose from the fuel filter and putting it into a bucket. (you could also use the pump to empty the tank instead of siphon if it was working as expected. –  Nathan L Dec 12 '13 at 21:32
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@NathanLiddle ... Actually, the fuel pump should not come on until the key is put into the run position (prior to starting). The better option for testing is to get a fuel pressure gauge and attach it to the Schrader valve. You would have to cut the fuel line to do as you suggest. The gauge is the safe way to do it. To the OP, the fuel pump is spot on. Since they have to remove the fuel tank to get to it, a price of $500 is reasonable. –  Paulster2 Dec 13 '13 at 23:31
    
If this solved your problem, you should accept your own answer to your question - this will help leave a trail of breadcrumbs for the next person who has the same problem. –  Bob Cross Dec 16 '13 at 15:29
    
@bob I was had to wait for three days before o could do that :) –  Earlz Dec 16 '13 at 15:42

You may wish to read up on gasoline ethanol phase separation. This is an unfortunate scenario where ethanol in your gasoline blend absorbs too much water from the atmosphere and separates into two layers. The bottom layer contains a water/ethanol mixture which kills the engine, the top layer contains a rich mixture of gasoline and a smaller portion of ethanol. When temperatures drop, phase separation occurs at a lower water concentration level.

If that has happened in your car you will want to siphon all of the gas out of the tank and refill with a fresh tank. You may also want to disconnect fuel line from the fuel pump and flush the line as well.

I don't know if this has happened in your case, but it is a known problem with the US ethanol blend requirements.

Here's one source on the subject: http://www.mossmotors.com/SiteGraphics/Pages/ethanol.html

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I thought gas doesn't separate like that unless left uncirculated for many days in extremely cold weather. That wasn't the case here –  Earlz Dec 12 '13 at 20:24
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Circulation doesn't matter, and extreme cold only makes it happen with less moisture than at higher temperatures. –  Nathan L Dec 12 '13 at 21:29

It does seem like a fuel system problem. Not having been maintained properly, as you say, would only make any problems worse.

You need to have a scan on the system. A scanner off of the net such as Torque Pro, or similar, may point you in the right direction of the fault before, that visit to your favourite repair shop.

You mention you might think you have ice in the fuel lines. Here in the UK, a government directive is requiring fuel refiners to add a percentage of 'bio' to their fuels, especially diesel. This is on-going to reduce emissions. An increasing number of break-downs and non-starts are being blamed on bio clogging fuel filters on vehicles using these fuels, made worse in colder weather.

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Well I'm in the US so unless you mean ethanol I don't think Bio would be my problem. –  Earlz Dec 12 '13 at 16:34
    
Ethanol also has water separation, breakdown, and clogging issues. Normally not too bad in recent cars, but can be very bad in older cars and carb'd motorcycles. –  Brian Knoblauch Dec 12 '13 at 21:29

It could either be a bad fuel pump or a bad throttle positioning sensor.

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