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    Idle air control valve?

    Hi
    Anybody have any luck cleaning the iacv?


    Motor City Patrick
    1988 MGM

    #2
    I have heard it is possible depending upon it's condition. I cleaned the one on my '87 GM along with the TB and it worked. Then again, there weren't really "crusty"!


    "Hope and dignity are two things NO ONE can take away from you - you have to relinquish them on your own" Miamibob

    "NEVER trade your passion for glory"!! Sal "the Bard" (Dear Old Dad!)

    "Cars are for driving - PERIOD! I DON'T TEXT, TWEET OR TWERK!!!!"

    Comment


      #3
      Some have. If it's causing trouble, and it's the original on your '88, I would replace it with a new OEM one.

      Then again, they're not that hard to get to on the EFI 5.0. If it needs cleaning every so often...meh. '91-95 4.6 on the other hand, replace the miserably located thing and be done.
      1990 MGM: $50 E7 heads, HO cam, Holley SysteMAX lower intake, HO upper intake with an Explorer TB. LSC ECM. Lincoln logs into stock dual exhaust. K&N drop in air filter. Wide ratio AOD, 2400 converter with a 3.08 one tire fire out back. Car is less slow now. Then there's the '92 Beater. Dual 2.25" exhaust with shiny tips. Rumbles nice. Super slow. Burns oil too.

      Comment


        #4
        the original on my 88 has been cleaned and works great to this day. I've never pulled it off the throttle body though. I just open the throttle and hose out the holes that go to it with carb cleaner when I clean the carbon out the the TB. If you have to take it off... get a new gasket. The old one will probably tear.

        Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
        rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)
        Originally posted by gadget73
        ... and it should all work like magic and unicorns and stuff.
        Originally posted by dmccaig
        Overhead, some poor bastards are flying in airplanes.

        Comment


          #5
          Worth trying to clean it before replacing. Won't take but a few minutes and a couple honks of cleaner.
          86 Lincoln Town Car (Galactica).
          5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

          91 Lincoln Mark VII LSC grandpa spec white and cranberry

          1984 Lincoln Continental TurboDiesel - rolls coal

          Originally posted by phayzer5
          I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

          Comment


            #6
            Can you just buy the gasket at the chain auto parts stores?


            Motor City Patrick
            1988 MGM

            Comment


              #7
              Carb cleaner works the best?


              Motor City Patrick
              1988 MGM

              Comment


                #8
                I use specifically made TB cleaner but some folks have used carb cleaner. Some of the Fords have a "coating" on the TB so hence the special TB cleaner. Not sure which ones have it but have always used TB cleaner. It may be more expensive but I'll live!


                "Hope and dignity are two things NO ONE can take away from you - you have to relinquish them on your own" Miamibob

                "NEVER trade your passion for glory"!! Sal "the Bard" (Dear Old Dad!)

                "Cars are for driving - PERIOD! I DON'T TEXT, TWEET OR TWERK!!!!"

                Comment


                  #9
                  Thanks


                  Motor City Patrick
                  1988 MGM

                  Comment


                    #10
                    One more question. Just trying to figure out if my idle air control valve is bad or because of the extreme weather we are having in Michigan. How long will it idle fast, when you first start it up in the morning? Its been 0 degrees here. It idles fast. Then it idles low after about 10 minutes. Is that normal? Is there a heating element in the TB? Or just the heat from the motor, to knock the idle down?


                    Motor City Patrick
                    1988 MGM

                    Comment


                      #11
                      Originally posted by 1988 Grand Marquis Pat View Post
                      One more question. Just trying to figure out if my idle air control valve is bad or because of the extreme weather we are having in Michigan. How long will it idle fast, when you first start it up in the morning? Its been 0 degrees here. It idles fast. Then it idles low after about 10 minutes. Is that normal? Is there a heating element in the TB? Or just the heat from the motor, to knock the idle down?


                      Motor City Patrick
                      The idle air valve is operated by an electric stepper motor, controlled by the ECU. There is no "heating element" like what modulates the choke on a carburetor (there is a coolant loop through the EGR spacer, but that is not related to idle function). The 5.0 SEFI generally runs at high idle for 15 seconds or so, then drops to an intermediate idle speed until it starts to warm up, at which point idle speed slows to "warm" idle. If this final warm idle speed is what takes your car 10 minutes to achieve, I'd say that isn't out of the question in 0-degree weather if the car is outside.
                      RyPow
                      1987 LTD Crown Victoria LX sedan - The "Sand Box" - 73K, towing package
                      1987 LTD Crown Victoria LX Tutone Tudor - '96 Explorer 5.0 + 5spd swap in the works
                      1985 Lincoln Town Car Cartier - previously owned by "navguy12" from thelincolnforum.net
                      2007 Lincoln Town Car Signature Limited, 102k, daily driver
                      2006 Mercury Grand Marquis LS, 115k, winter beats
                      1977 Lincoln Continental Town Car, 42k
                      2012 F-150 5.0L 4x4, HD payload pkg (towing/hauling)
                      2015 Toyota RAV4 XLE AWD (better half's)

                      Comment


                        #12
                        If it doesn't gradually wind down but does a high idle and then a drop to a low idle, the IAC is probably sticky. They can act like that if there is gunk in there. All thats in there really is a solenoid with a ball on the end of it. If the mechanism is gummed up, it will tend to over-shoot where it wants to be instead of slowly lowering the engine speed.


                        86 Lincoln Town Car (Galactica).
                        5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

                        91 Lincoln Mark VII LSC grandpa spec white and cranberry

                        1984 Lincoln Continental TurboDiesel - rolls coal

                        Originally posted by phayzer5
                        I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

                        Comment


                          #13
                          Cool post Gadget!
                          I've had those off before and I wonder, can you move that plunger by hand without wrecking it? I've fogged cleaner in them but it would be nice to know if you can move them through their range of travel without killing it.
                          1985 LTD Crown Victoria - SOLD
                          1988 Town Car Signature - Current Party Barge

                          Comment


                            #14
                            Found this thread on a mustang forum that describes to to test it in detail:

                            Originally posted by http://forums.corral.net/forums/5-0-5-8-engine-tech/735555-how-check-if-your-iac-good-working.html
                            Actually, I just tested my IAC today. Get an ohmeter (or multimeter), disconnect the IAC harness connector, and touch the ohmeter's leads to the two pins on the end of the IAC. The impedance should be between 7 & 13 ohms. Next, test the impedance of each pin against the metal housing of the IAC. Each pin should not have an impedance lower than 10,000 ohms. If either of these two tests fail, junk the IAC and buy a new one.

                            Also, don't forget to test the voltage of the signal coming out of the ECU to the IAC harness connector. Set your ignition to key on, engine off. Set your multimeter to DC volts and, using thin meter probes (I used two sewing needles), touch the two pins in the IAC harness connector. If you have either + or - 12V, than you have a short which you must trace back to the ECU's harness connector.

                            Lastly, if everything checks out OK, disconnect that IAC valve, take it inside, and disassemble it. Remove the two screws and separate the plunger body from the solenoid. Here you can push the plunger by hand and check for blockages. Spray the plunger body with carb cleaner and scrape out any carbon gunk. Reassemble and follow the usual idle set procedure.

                            Also, when you set the throttle plate you should back out the screw completely. Next, place a .010 feeler gauge in front of the stop. Tighten the screw until it just touches the feeler gauge. Remove the feeler gauge and turn the screw 1.5 more times. Your idle setting is done. Next, readjust your TPS for < 1.0 volt and reset the ECU.
                            Thinking out loud though, couldn't you just manually supply voltage to the IAC and check to see if the plunger moves?

                            '78 LTD | '87 Grand Marquis | '89 Crown Vic (RIP) | '91 Grand Marquis (RIP) | '94 Town Car (RIP) | '97 Town Car (RIP)

                            Comment


                              #15
                              Do not apply voltage to that thing. You'll fry it. Ask me how I know.

                              The ECM doesn't apply steady voltage to it, it pulses it if I recall.
                              1990 MGM: $50 E7 heads, HO cam, Holley SysteMAX lower intake, HO upper intake with an Explorer TB. LSC ECM. Lincoln logs into stock dual exhaust. K&N drop in air filter. Wide ratio AOD, 2400 converter with a 3.08 one tire fire out back. Car is less slow now. Then there's the '92 Beater. Dual 2.25" exhaust with shiny tips. Rumbles nice. Super slow. Burns oil too.

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