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  1. #1
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    Default Bad mass air flow sensor symptoms?

    Ive been having an issue with my speedometer. It jumps up and down. When its down the power feels a little down as well. Nothing too drastic. Someone seems to think it is the mass air flow sensor going bad. Any opinions?

  2. #2
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    Default Re: Bad mass air flow sensor symptoms?

    Any CEL's? It definitely sounds like something electrical or vehicle speed sensor related. How much is it jumping? Is the actual vehicle speed jumping (the car bucks and stalls) or just the indicated speed? If it's the latter, it's probably not your MAF.

    Check all your grounds and the wiring to the cluster.
    Joe

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  3. #3
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    Default Re: Bad mass air flow sensor symptoms?

    The speedo jumps, sometimes sits at 0. Car never stalls or hesitates bad. Almost like you can feel a little bog down in power when it drops. Best way to describe the feeling when it happens would be to say it feels like the parking brake is slightly put on - and off. but its coming from up front. By no means do i mean the feeling of completely pulling the e break, but just a little slowdown or something. Its weird man. I always thought it could be electrical. I dont even go there.

  4. #4
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    Default Re: Bad mass air flow sensor symptoms?

    Definitely sounds like something electrical. First step would be to locate the grounds in the engine bay and make sure they are all clean. Make sure the wires don't look compromised. If you have a multimeter, check the resistance of each ground to double check the connection. This may even be a good time to upgrade the ground wires to something a bit more beefy.

    If it was a MAF issue, the car would actually buck from the bad signal since the ECU wouldn't be able to read the air flow correctly. Unplug it and try to drive. You'll see what I mean haha
    Joe

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  5. #5
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    Default Re: Bad mass air flow sensor symptoms?

    HEaT is right. Your symptoms definitely don't sound MAF related. Do you have confidence in the "Someone seems to think it is the mass air flow sensor..." as being qualified to make such a diagnosis with no testing - especially when you have a speedometer problem that occurs at the same time?

    Follow hEaT's recommendations and don't just start throwing parts at it without good reason for suspicion. Going after the grounds is definitely a great place to start.

  6. #6
    Senior TEAM Member polarisman14's Avatar
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    Default Re: Bad mass air flow sensor symptoms?

    It could be electrical or MAF related but who knows. I had the exact same problem with my ranger, but not until I put on the "true" cold air intake and sucked some water up. The truck would drive normally most times but every once in a while the speedometer would operate erratically and during the period of time that was happening the truck felt relatively sluggish and low on power. Never actually found out what the root cause of that problem was, but the MAF, TPS, and IAC valve were the only things electrical that the airflow encountered before it entered the TB, manifold, and combustion chamber.
    --UnFocused1-- AKA >>Matt<<

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  7. #7
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    Default Re: Bad mass air flow sensor symptoms?

    If the MAF was bad enough to cause that performance, I think it would throw a CEL. If you want to rule out a dirty one, grab a can of MAF cleaner from your local auto parts store. Either grab the right size safety torx, unplug it and pull the actual sensor from the housing CAREFULLY and clean it or unplug the sensor and remove the entire housing from the intake.

    When cleaning the sensor, be very careful because it is a delicate piece of electronics. Don't touch the wire inside either. Spray the cleaner liberally and clean off all angles of the wire. Make sure it completely dries before plugging the sensor back in. I'm 99% sure this is not the issue of a dirty MAF, but it could be compounding a smaller issue. It doesn't hurt to clean it either way especially if you have a oiled cone filter.
    Joe

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  8. #8
    Senior TEAM Member polarisman14's Avatar
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    Default Re: Bad mass air flow sensor symptoms?

    ^^Fact. On a side note, you can use starting fluid to clean the MAF, it's a lot cheaper and its the same thing.

    I believe the issue with mine was that it took so much water in that it began to rust. In my experience, I replaced the MAF once and this cleared up the problem until the next time I drove in the rain, even after complete revamping of my splash guard design and filter location .

    The inside of the old assembly was coated in rust-colored dust, which I am assuming was from the steel mesh on the air filter. I also believe the legs on the resistor are made of metal that can rust, which may lead to intermittent MAF issues.
    --UnFocused1-- AKA >>Matt<<

    --89 Starion SHP, MPI Swap, 400hp+ or bust!--
    <03 Ranger 4.0L "SKIGOD" DD: CAI, custom side exhaust, audio>
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  9. #9
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    Default Re: Bad mass air flow sensor symptoms?

    I have a cold air intake on the car. Im sure it has taken on water. Maybe I should just take it to a mechanic.

  10. #10
    [FJ] Specialist G-forces's Avatar
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    Default Re: Bad mass air flow sensor symptoms?

    Are you thinking of taking it to a mechanic, because you don't want to check the grounds? Do you live up north? Because it's way too cold for me to work on a car right now.

    But if you CAN check them, that could have something to do with it for sure, or an alternator pigtail, or an alternator power surge/dip from loosing regulator control.

    Save your money if it's warm. The grounds are easy to find.
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  11. #11
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    Default Re: Bad mass air flow sensor symptoms?

    I am acctually in florida. I really dont know much about my car. I wouldnt know where to look to find the grounds. I have watched my buddy back home in michigan dothings like put the cold air intake on, and change the breaks, but thats about it. Would anyone care to describe where to look for the grounds? Im not an idiot, but maybe I come off as one right now! Thanks for the help

    Matt

  12. #12
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    Default Re: Bad mass air flow sensor symptoms?

    This should give you a good start:

    http://www.focuscanada.net/forum/ind...showtopic=8122
    Joe

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  13. #13
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    Default Re: Bad mass air flow sensor symptoms?

    Thanks for all the imput HEAT. Itmade me think of something else when you said "electrical". Every couple months Ill get in my car and my radio presets will be all reset like the power to it went for a split second? Could this be something else having bad wires or bad ground might do?

  14. #14
    Senior TEAM Member polarisman14's Avatar
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    Default Re: Bad mass air flow sensor symptoms?

    The other thing i was thinking of is that if its one of the older models (00-04, not sure what dates the recall is effective for) there was an issue with the focus where the positive battery cable would arc to the firewall (or something along those lines). If either that or any of your negative grounding straps or anything are loose or severed, it could cause a problem similar to that, especially if it resets the presets and whatnot. That tells me it's not the MAF.

    Also, I heard of one case where the motor mounts were worn out and that caused one of the power or ground cables to get severed by the alternator (or something behind the engine).

    Basically, if you take it to the mechanic, tell him to check all of the power and ground cables, because that sounds like a more likely cause of the problem
    --UnFocused1-- AKA >>Matt<<

    --89 Starion SHP, MPI Swap, 400hp+ or bust!--
    <03 Ranger 4.0L "SKIGOD" DD: CAI, custom side exhaust, audio>
    >86 Ninja 250R "GOPED" 50+mpg bullet: Slip-ons, Pod filters, Jet kit, LED signals, custom plate bracket<

  15. #15
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    Default Re: Bad mass air flow sensor symptoms?

    Quote Originally Posted by justgosurfing
    Thanks for all the imput HEAT. Itmade me think of something else when you said "electrical". Every couple months Ill get in my car and my radio presets will be all reset like the power to it went for a split second? Could this be something else having bad wires or bad ground might do?
    No problem. That is probably from the same problem.
    Joe

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