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Car starts, Idles rough, then dies

Hi, I have a 98 Ford Escort. A few months ago, we got a check engine light and some rough idling, and had to change the O2 sensor. So we did that, and a few months after that, the car would just start, run for a few seconds, then sputter dead.



After googling like crazy, my husband and I came to believe it was the MAF, because we can hear the fuel pump before we go to turn it over.



We cleaned the MAF, and that didn't work, so we ended up getting a used one, which doesn't work. Further googling, led us to clean the AIC valve thingy, and check hoses for air leaks. Now, if we take the MAF off it will run a lot longer, unless you give it gas.



So we are just confused now. Any ideas?
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Comments

  • edited March 2010
    You must have a check engine light on - no?
  • edited March 2010
    we dont now, i cant remember if we started with one or not
  • edited March 2010
    ??

    Its either on or its not. You can make the car run at least for a while, right? Once the car is running is the light on or not? (It always lights up w/ the other dash lights when you first start it up).

    You need to get the error codesout of the computer. If the car will actually go, many large-chain auto parts stores will read these for free. If you can't get the car there you can either buy a cheap code reader ($60 or so) or some places will loan them out - which usually means "buying" one and getting a full refund when you return it.

    The codes look like this: "P1234" - you need those exact codes.
  • edited March 2010
    Yeah I know. What I meant is, it is definitely NOT on right now, I can't remember if when we started trying to fix it months ago if it ever came on and is now off, because we have reset the computer, and all that. The car doesn't drive, and we haven't been able to drive it for months. It starts, runs for like, 5 seconds then dies.
  • edited March 2010
    I agree with Cigroller that the first step will be to try to scan for stored codes.

    I think what you're doing when you disconnect the mass airflow sensor is partially compensating for a poor fuel metering problem, causing it to idle a bit longer before shutting down. Bottom line, I think you have a fuel delivery problem. Either a plugged filter (low probablility), a bad fuel regulator (low probability), or a dying fuel pump (high probability).

    A bad temp sensor or manifold absolute pressure sensor are IMHO low probabilities but possibilities.

    It dying when you give it gas is a clue to me. That's telling me that the ECU may be reading the throttle position sensor and lengthing the injector pulsewidth but rather than giving the engine more gas it's simply dropping the small amount of fuel pressure that exists, starving the engine.

    In short, check your fuel supply line pressure and post back.
  • edited March 2010
    ok cool, do i check for fuel pressure? Hope its not the fuel pump, well at this point i just hope to fix it so lol..guess ill be happy if it is. Thanks for the help, ill post again when my husband gets back and we try some stuff out lol
  • edited March 2010
    Yes, check for fuel pressure. You'll need a gauge. The fuel pump is very easy to change - you get to it through an access hole under the back seat. They're a little pricey but not having to drop the tank is somewhat priceless.

    You cleaned the IAC - but did you check it? Get the electrical specs and take a multimeter to it and its power supply. Though you can check fairly quickly on it my seeing if it will stay running with a little throttle. If some throttle can keep it running then certainly check the IAC.
  • edited March 2010
    checked the pressure, and there wasn't any, so I think he's gonna replace the pump. We thought of checking the fuel regulator, but I guess the 98 only has a sensor, with no fuel return. Weird.

    Very awesome that we can do it from the back seat, He was happy about that at least, thanks for the help! Guess i'll come back if this doesn't work haha, but I think it will
  • edited March 2010
    Presumably "there wasn't any" with the the fuel pump fully energized? See, if there wasn't any fuel pressure at all - as in zero psi - then the car would never run at all - even a little bit - for 5 seconds or 1 second. So hopefully he didn't just stick the pressure gauge on and that was it. My car has been sitting a couple of days (hasn't needed to go anywhere) and I'm sure the pressure is probably zero. A few cycles of the key will pump it up to spec.

    Does the fuel pump run when the key is turned? If the fuel pump runs but you get little to no fuel pressure, then you replace the pump. You you turn the key and pump doesn't run at all then you check the electrical supply to the pump first - including relays/fuses.
  • edited March 2010
    well there was 5 psi when the engine ran for the few seconds that it does and 0 when off. He did a few cycles of the key and it still was around 5 psi. when it does run for a few seconds the pump does run but there's still no pressure so I guess its a new pump! weeeee! Im just happy to know what it is LOL, *knock on wood* When we get around to replacing it I'll let ya know, cuz if its not that then Im just gonna scream.
    Thanks for the help
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