Help me create the "Surging Idle Checklist"

Discussion in 'Fox 5.0 Mustang Tech' started by jrichker, Apr 10, 2005.


  1. HISSIN50

    HISSIN50 "How long does it take to get help in here? SN Certified Technician

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    The VSS and computer will keep the rolling idle at ~1100-1500 RPM to keep the motor from stalling. This is normal (otherwise, when you cranked the wheel, hit the brakes, etc, it could try to stall).
     
    #101
  2. super302

    super302 I'd do anything for free Bapples

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    The 10 pin connectors are kinda behind teh intake manifold, sorta hard to find :shrug:
     
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  3. crenth5

    crenth5 New Member

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    What is the VSS? Also, no power steering on my car. My car didn't do this all the time when I got it, but it would do it occassionally. Now it does it all the time. Is the grommet and wire mesh part of the pcv valve?
     
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  4. jrod92

    jrod92 Member

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    Sticking idle

    I have tried everything on the checklist checking all sensors, cleaning all electrical connections ect. andn my idle still has a problem. when i push the clutch in while coming to a stop or shifting it revs up to about 2500 rpm and sticks until i let off. when driving it also sticks feeling like i am in cruise control all of the time.
     
    #104
  5. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    An idle that sticks high and won't come down unless you turn the key off & restart the engine is a sign of a bad TPS

    The 10 pin connectors are seen in this photo. Photo courtsey of Tmoss & Stang&2birds...

    [​IMG]

    See http://www.veryuseful.com/mustang/tech/engine/ for lots of good inflo
     
    #105
  6. crenth5

    crenth5 New Member

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    Where can you buy a new throttle position sensor?
     
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  7. HISSIN50

    HISSIN50 "How long does it take to get help in here? SN Certified Technician

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    Any auto parts store should sell them, as well as the dealer, as well as resto houses.

    Good luck.
     
    #107
  8. jrod92

    jrod92 Member

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    TPS test


    Could the TPS still have a problem even if i had it tested at the auto parts store? I also had them test a new one to check for any differences. This problem is getting very annoying.
     
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  9. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    Yes. It may have some of the carbon from the resistor piling up by the slider. A TPS is nothing more than a variable resistor, just like the volume control on a radio. How many old radios have you seen that are scratchy and hard to get the volume set on?
     
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  10. jrod92

    jrod92 Member

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    still sticking

    I just replaced my tps and the throttle is still revving and sticking at 2500 everytime i push the clutch in. Does it take the computer time to adjust for the new sensor? If not what other suggestions can you offer???
     
    #110
  11. willys1

    willys1 Banned

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    I finally put a new IAB in and no dice,it still happens.I think my egr switch/valve is bad!! Im trying new ones tommorow,I'LL let you know how I make out!!
     
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  12. crenth5

    crenth5 New Member

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    I replaced my TPS and it works a lot better now.
     
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  13. willys1

    willys1 Banned

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    Fixed it!! It was a bad vaccum on the lower intake :notnice:
     
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  14. jrod92

    jrod92 Member

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    where exactly was it on the lower intake?
     
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  15. ArtMan

    ArtMan Founding Member

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    Supercharger

    One other cause of a surging idle that may have already been addressed (I didn't read every post of the past 5 pages) is one that afflicts supercharger owners.

    After installing your Vortech you may find that the engine won't idle correctly. If you are able to rule out the other causes noted above, you should verify the crankcase is vented properly. This doesn't effect all sc owners the same, but be assured its an annoying problem.

    The nipple at the oil filler can suck in air at idle. If this happens air is ingested into the combustion chamber that is not metered by the MAF. An erratic or sticky high idle results. When Vortech first sold their kits they had you run a hose to the filter "area". Now they include bosses so you may run a hose from that nipple to the intake elbow that fastens to the compressor. Since I own an older kit I had to order the updated elbow special.

    But it cured my surging idle instantaneously and the car runs like silk (even with my cam)

    Hope this helps. :flag:
     
    #115
  16. rip-cord

    rip-cord Founding Member

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    I was reading the posts and I just wanted to know what does clock the MAF mean and how do you go about cleaning it.

    The stang was fine before I installed the CAI but now on a cold start it stalled this morning and I started it up and it would jump from 1,500 right down to 400 to 500 and almost stall again. When warm it worked fine no problems.

    The only thing that changed was the CAI so what should I be looking at?

    Thanks
     
    #116
  17. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    Clocking the MAF means turning the MAF housing to a different position. This changes the airflow through the MAF and may help some idle problems.

    Some theory & background info is helpful now...

    There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables.

    The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).

    The MAF output varies with RPM which causes the airflow to increase or decease. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow.
     
    #117
  18. rip-cord

    rip-cord Founding Member

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    Thanks, I will give that a try tonight. I figured it had to be related to the MAF since I didn't have the problem before the CAI and the MAF is the only thing that I would have touched.

    I will let you know how it goes.

    :hail2:
     
    #118
  19. 1redprix

    1redprix New Member

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    Stalling

    I Put Afr 165cc Street Heads On My Car This Past Winter...guess What ...it Idled Low And When I Came To A Stop It Stalled...so I Checked Everything On This List...it Was A No Win Situation , And I Was Mad !!! I Put A Idle Adjuster Plate Between The Throttle Body And Iac And Guess What ...with A Few Turns Out And 1 Turn Back In....idles Like A Charm And No More Stalling...thanks Stangnet Members..
     
    #119
  20. rip-cord

    rip-cord Founding Member

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    I just wanted to let you know that I cleaned the MAF and while I was at it I gave the throttle body a cleaning as well.

    Worked like a charm, idles better then before.

    Thanks for the help.

    :banana:
     
    #120

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