IACV/ Stepper Motor / Vacuum leak help
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Thread: IACV/ Stepper Motor / Vacuum leak help

  1. #1
    FRESHMAN ROVER signalMTB's Avatar
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    IACV/ Stepper Motor / Vacuum leak help

    My dad's '95 RRC has a high idle at start up, throws the '48' stepper motor code. I've cleaned the stepper motor (IACV) and MAF plug. New IACV is $160 so not super interested in just trying a new one. Might be a vacuum leak...never traced or replaced or diagnosed a vacuum leak before. Any thoughts or help?
    1994 RRC LWB
    2005 RR L322 HSE
    1997 NAS D90 SW
    1988 951S silberosa
    3 prior '95 RRCs, of which I really miss one of them

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  3. #2
    FRESHMAN ROVER
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    Re: IACV/ Stepper Motor / Vacuum leak help

    As a test, you should switch the IACV with the one from your LWB or NAS.

    Vacuum leaks are generally found via a smoke test. You can also use some starter fluid, or carb and choke cleaner, around where you think the leak is while the engine is running. Lots of information about alternative testing with a google search.

    Even simpler, check to make sure that non of the vacuum lines have just fallen off.
    1990 Range Rover - http://www.defendersource.com/forum/...irs-60356.html
    1995 Range Rover LWB - daily driver

  4. #3
    FRESHMAN ROVER
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    Re: IACV/ Stepper Motor / Vacuum leak help

    Stepper from a Chevy Astro van will work & you can get it at NAPA. Don't remember which year so do a search. I want to say late '80s.

    Have a read here..... Deals on Stepper Motors?
    Last edited by KK88RRC; April 21st, 2017 at 08:43 AM. Reason: added link
    Kevin
    88 RRC "Audrey"

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  6. #4
    FRESHMAN ROVER signalMTB's Avatar
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    Re: IACV/ Stepper Motor / Vacuum leak help

    Quote Originally Posted by rangerover View Post
    As a test, you should switch the IACV with the one from your LWB or NAS.

    Vacuum leaks are generally found via a smoke test. You can also use some starter fluid, or carb and choke cleaner, around where you think the leak is while the engine is running. Lots of information about alternative testing with a google search.

    Even simpler, check to make sure that non of the vacuum lines have just fallen off.
    ok thanks, at this point I'm trying to locate a vac hose diagram. Ordered a IACV, due in tomorrow. $45 at autozone
    1994 RRC LWB
    2005 RR L322 HSE
    1997 NAS D90 SW
    1988 951S silberosa
    3 prior '95 RRCs, of which I really miss one of them

  7. #5
    FRESHMAN ROVER whiteboxer's Avatar
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    November 15th, 2011
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    Re: IACV/ Stepper Motor / Vacuum leak help

    I hope the new stepper motor resolves your high idle issue. I have replaced my IACV a few times (it seems like they last 5-6 years on my '95 RRC LWB). Just be sure that you thoroughly clean the pot before installing the new unit. Best of Luck!

  8. #6
    FRESHMAN ROVER nazdackster's Avatar
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    August 22nd, 2010
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    Re: IACV/ Stepper Motor / Vacuum leak help

    I used the "chevy astro" or whatever it was... Mine runs fine but I think maybe that motor has fewer steps / faster close rate, etc. Mine starts out high idle as normal, but seems to shut the air off a little fast, faster than the system can recognize that it needs to open the valve a little again to maintain correct idle. I'd guess the rover has more counts to close the valve. Mine actually stalls out just after start when warm sometimes. Technically, this shouldn't happen when set with base idle set correctly, but mine hasn't been touched so I haven't messed with it. Can't prove it but would like to try a genuine one to see if it makes a difference.
    1994 County LWB, Plymouth Blue
    2002 P38 (Sold)

    2008 LR3 HSE
    1980 Toyota FJ40
    1984 Jeep CJ-7

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