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  1. #1

    Default 2.3L High idle, codes


    Hello all, just picked tup 92 mustang, 2.3l, 100K miles. Clean. Has high idle, did a visual search and found PCV not connected, and corrected this. Also found vaccum line to EGR loose, and fixed this, however still idles high (probably 1000-1200 RPM, tach inop so not certain). Runs fine otherwise.

    Pulled codes and got:
    10,20
    116
    114
    223
    332
    172
    332
    as I recall

    Codes were air charge temp sensor voltage out of range, coolant temp hi or lower than expected, intermittent signal from DPI, EGR out of range (maybe from leaking vacuum line prior to fixing).
    Im not seeing alot here that would contribute to the motor idling high (running lean), but would the air charge temp sensor be the best place to start?? Seems like this could cause a lean condition.
    Also, the tach sits at 3400 rpm when energized. Is there a common cause of this?
    Thanks a ton.
    Russ


  2. #2
    FEP Super Member webestang's Avatar
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    Still could be a vac line. I'd recheck all the lines to make sure they are not cracked and fit snug to the connections.

    Found this on a Ranger forum.....

    First thing I would do is to track down the high idle cause.
    Engine cold idle will be 900-1,000 rpm
    Warm idle 700-750 rpm

    With engine warmed up and idling, unplug the connector for the IAC valve, engine rpm should drop down to 500-600 rpm.
    If idle doesn't drop that means computer is not setting the high idle, most likely cause is a vacuum leak.
    The IAC valve is a "controlled vacuum leak" that's how the computer raises and lowers the idle for cold and warm engine idle, it opens and close the valve to let more or less air into the intake, if your idle doesn't change from cold to warm engine temp then IAC valve may be stuck, these can be cleaned.
    Just as an FYI, on all fuel injected engines IAC valves are used, and when you first start these engines the computer will open the IAC valve all the way then close it to set cold or warm idle speed, so the engine should go to high idle then drop after starting, if that is not happening then cleaning the IAC valve should be the next step.
    If IAC valve is working you can start by removing one vacuum line at a time from the intake and plugging that hole with your finger, if idle drops you found a leak, check that hose and the device at the end of that hose.
    If all hoses check out as OK, then you will need to spray some carb cleaner or starting fluid around the intake gasket and see if spraying at a certain spot changes rpm, if so then there is a vacuum leak at that spot.
    Vacuum leak can also cause a miss as it leans out the idle fuel mix.
    If unplugging the IAC valve lowers the idle to 500-600 rpm then computer is setting the idle that high for some reason.
    Could be computer is not being told that engine is warmed up, that's done by the ECT sensor, but you would usually get a CEL(check engine light) if that was the case.
    Could be a MAF(air flow) or MAP(air pressure) sensor giving the computer the wrong air readings.

    Scotty
    1985 Fox Notch 4-banger Ranger tube header Eastwood Royal Blue
    1988 Fox LX 5.0 AOD Vert BBK 170mph speedo Candy Apple Red
    1999 Mustang Coupe V6 Auto Chrome Yellow -Daily Driver.
    Past Pony's.....
    68 Coupe Inline-6 3-Speed-Man. Primer
    78 II Hatch 302 3-Speed-Auto Sunroof Black
    81 4-Eye Coupe 4-Banger 4-Speed-Man. White

  3. #3

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    I did just notice that the ground strap off the back of the head is not bolted to ground. Where is this supposed to be mounted (what bolt on firewall)??

    Thanks,.

  4. #4
    FEP Super Member webestang's Avatar
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    There should be an existing hole to bolt to the firewall or just drill a new one. Just make sure you you strip all the paint around the hole to bare metal to mount the ground.

    Scotty
    1985 Fox Notch 4-banger Ranger tube header Eastwood Royal Blue
    1988 Fox LX 5.0 AOD Vert BBK 170mph speedo Candy Apple Red
    1999 Mustang Coupe V6 Auto Chrome Yellow -Daily Driver.
    Past Pony's.....
    68 Coupe Inline-6 3-Speed-Man. Primer
    78 II Hatch 302 3-Speed-Auto Sunroof Black
    81 4-Eye Coupe 4-Banger 4-Speed-Man. White

  5. #5

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    well it still idles high, but idle drops to normal when i pull the connector to the iac. So i suppose that ill replace the air charge sensor next since there was an out of range code for this. Any other thoughts??

    thanks alot!

  6. #6
    FEP Super Member webestang's Avatar
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    Buy the FORD IAC.......!!!!!!! I went through 2 aftermarket ones on my 88 5.0 and after I put a Ford one in it has been fine for years.

    Scotty
    1985 Fox Notch 4-banger Ranger tube header Eastwood Royal Blue
    1988 Fox LX 5.0 AOD Vert BBK 170mph speedo Candy Apple Red
    1999 Mustang Coupe V6 Auto Chrome Yellow -Daily Driver.
    Past Pony's.....
    68 Coupe Inline-6 3-Speed-Man. Primer
    78 II Hatch 302 3-Speed-Auto Sunroof Black
    81 4-Eye Coupe 4-Banger 4-Speed-Man. White

  7. #7

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    Quote Originally Posted by webestang View Post
    Buy the FORD IAC.......!!!!!!! I went through 2 aftermarket ones on my 88 5.0 and after I put a Ford one in it has been fine for years.

    I dont think my IAC is bad. Looked clean, no code for it.

  8. #8
    FEP Super Member webestang's Avatar
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    Quote Originally Posted by Atengnr View Post
    I dont think my IAC is bad. Looked clean, no code for it.
    That's good. Also check the throttle position sensor.

    Scotty
    1985 Fox Notch 4-banger Ranger tube header Eastwood Royal Blue
    1988 Fox LX 5.0 AOD Vert BBK 170mph speedo Candy Apple Red
    1999 Mustang Coupe V6 Auto Chrome Yellow -Daily Driver.
    Past Pony's.....
    68 Coupe Inline-6 3-Speed-Man. Primer
    78 II Hatch 302 3-Speed-Auto Sunroof Black
    81 4-Eye Coupe 4-Banger 4-Speed-Man. White

  9. #9

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    Quote Originally Posted by webestang View Post
    That's good. Also check the throttle position sensor.
    replace air temp sensor and still no change. Ill rescan the ecm to see whats changed i suppose.

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