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1987 Town Car running rich? High IDLE. Poor MPG

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    1987 Town Car running rich? High IDLE. Poor MPG

    1987 Town Car. Stock Drivetrain with Dual Exhaust no Cats. Recent Spark plugs, wires and cap, no rotor. Averaging 15mpg. I know this car will average 18 or more like it used to when it was like new. I suspect the elimination of the catalytic converters with my new dual exhaust is the reason that it is running rich. What can I do about this? Idling high, cruise control is out as well.
    87' Lincoln Town Car Stars + Stripes. Explorer GT40P, Anderson B31 Cam, Shorty Headers, FRPP 1.6 Rockers, A9L, Sn95 T5 Trans, 3:55 Limited Slip, GNX Rear Springs, LSC Turbines, 1.5 wheelspacers, Full Custom Dual 2.5/Flowmasters, 00 P71 Airtube, 19lb calibrated Maf, Summit Alum Radiator, King Cobra Clutch, Short throw Shfter, Energy Susp Trans Mount,
    Mods to come: Big Brake/Poly Front Swap, PI Front Swaybar, Addco 650 Rear Swaybar, Boxed Upper Rear Control Arms, 351/Alum Heads, FRPP Valve Covers,

    #2
    Sounds more like a vacuum leak.

    85 4 door 351 Civi Crown Victoria - Summer daily driver, sleeper in the making, and wildly inappropriate autocross machine
    160KMs 600cfm holley, shorty headers, 2.5" catted exhaust, 255/295 tires, cop shocks, cop swaybars, underdrive pulley, 2.73L gears.
    waiting for install: 3.27's, Poly bushings, boxed rear arms, 2500 stall converter, ported e7's, etc

    06 Mazda 3 hatch 2.3L 5AT (winter beater that cost more than my summer car)

    Comment


      #3
      Why do all that and no rotor? You were in there to do the cap! Could be vac or also check TPS, IAC and O2 sensors.


      "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


        #4
        Unless your rotor looked perfect you should always replace it when you do the cap etc. 5 bucks at the most.


        Converters on these cars have SFA to do with how much gas she burns, the o2 sensor is up in the exhaust manifold so it gets a signal pre-converter anyway in stock form. I got a bump in gas mileage when I went from a stock single exhaust to 2.25 dual pipes and no converters. A drop makes no sense, so a vacuum leak would be my first guess.


        do you know how to check for leaks?



        When you got rid of the converters, what was done to the air pump plumbing that used to run down to the cats?
        Last edited by 1990LTD; 09-24-2011, 03:23 PM.
        sigpic


        - 1990 Ford LTD Crown Victoria P72 - the street boat - 5.0 liter EFI - Ported HO intake/TB, 90 TC shroud/overflow, Aero airbox/zip tube, Cobra camshaft, 19lb injectors, dual exhaust w/ Magnaflows, Cat/Smog & AC delete, 3G alternator, MOOG chassis parts & KYB cop shocks, 215/70r/15s on 95-97 Merc rims

        - 2007 Ford Escape XLT - soccer mom lifted station wagon - 3.0 Duratec, auto, rear converter delete w/ Magnaflow dual exhaust

        - 2008 Mercury Grand Marquis Ultimate Edition - Daily driver - 4.6 2 valve Mod motor, 4R75E, 2.73s. Bone stock

        Comment


          #5
          I'm interested too.
          Since doing my HO swap; my first gas tank was 10mpg, my second gas tank was 12.5mpg.

          My major commute with the old lopo used to be 20miles to school and back, and 20mpg was common. 18mpg wintertime. 24mpg best tank ever.
          I now commute 5 miles to work, 5miles back. So I realize that shorter trips could be a part of it; and having fun with the new engine that first tank could have been part of the 10mpg. I also don't know if a just-rebuilt engine needs to break in a little; if internal frictions are high.
          But this had better not be a longterm average.

          So I'm interested in some of these responses also.
          Could an exhaust leak, such that the O2 sensor sees less exhaust, cause rich-running issues?
          Granted I have no idea if I'm running lean, rich, or just right-- worth finding a friend with a tailpipe sniffer?

          And I wouldn't mind a description of how to test for vacuum leaks. I presume the same smoke test I've used for emissions system leaks, would do the same job; and watch for a flow rate? flow rate = leak, no flow=contained? If there is flow, look for smoke somewhere?
          Last edited by BerniniCaCO3; 09-24-2011, 03:57 PM.

          Comment


            #6
            replace all the dead vacuum lines, you will have to pull the upper intake to get at a few.......little trick i use is to blow smoke into one of the vacuum lines and look for smoke to escape.

            i see no mention of changing the pcv valve screen and grommet the screen gets clogged and the grommet turns to rock.......the pcv hose also turns to rock

            1986 lincoln towncar signature series. 5.0 HO with thumper performance ported e7 heads, 1.7 roller rockers, warm air intake, 65mm throttle body, 1/2" intake spacer, ported intakes, 3.73 rear with trac lock, 98-02 front brake conversion, 92-97 rear disc conversion, 1" rear swaybar, 1 3/16" front swaybar, 16" wheels and tires, loud ass stereo system, badass cb, best time to date 15.94 at 87 mph. lots of mods in the works 221.8 rwhp 278 rwt
            2006 Lincoln Town Car Signature. Stock for now
            1989 Ford F-250 4x4 much much more to come, sefi converted so far.
            1986 Toyota pickup with LSC wheels and 225/60/16 tires.
            2008 Hyundai Elantra future Revcon toad
            1987 TriBurner and 1986 Alaska stokers keeping me warm. (and some pesky oil heat)

            please be patient, rebuilding an empire!

            Comment


              #7
              I second the PCV filter. Unless you like changing gaskets frequently...

              Comment


                #8
                high idle + poor economy almost always means vacuum problems. Yank the intake, change the hoses, and replace the PCV junk while you're in there. If the valve covers leak, change those too.
                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


                  #9
                  Allright guys. I just replaced the Rotor yesterday too. I will begin the rest of the project by next weekend. Hunting down any vacuum leak.
                  87' Lincoln Town Car Stars + Stripes. Explorer GT40P, Anderson B31 Cam, Shorty Headers, FRPP 1.6 Rockers, A9L, Sn95 T5 Trans, 3:55 Limited Slip, GNX Rear Springs, LSC Turbines, 1.5 wheelspacers, Full Custom Dual 2.5/Flowmasters, 00 P71 Airtube, 19lb calibrated Maf, Summit Alum Radiator, King Cobra Clutch, Short throw Shfter, Energy Susp Trans Mount,
                  Mods to come: Big Brake/Poly Front Swap, PI Front Swaybar, Addco 650 Rear Swaybar, Boxed Upper Rear Control Arms, 351/Alum Heads, FRPP Valve Covers,

                  Comment


                    #10
                    Allright guys. I just swapped a newer coil from a Foxbody 5.0 and replaced the Rotor yesterday too. I will begin hunting down the vacuum leak next. The car seems to be sucking down a quart of oil per week too.
                    87' Lincoln Town Car Stars + Stripes. Explorer GT40P, Anderson B31 Cam, Shorty Headers, FRPP 1.6 Rockers, A9L, Sn95 T5 Trans, 3:55 Limited Slip, GNX Rear Springs, LSC Turbines, 1.5 wheelspacers, Full Custom Dual 2.5/Flowmasters, 00 P71 Airtube, 19lb calibrated Maf, Summit Alum Radiator, King Cobra Clutch, Short throw Shfter, Energy Susp Trans Mount,
                    Mods to come: Big Brake/Poly Front Swap, PI Front Swaybar, Addco 650 Rear Swaybar, Boxed Upper Rear Control Arms, 351/Alum Heads, FRPP Valve Covers,

                    Comment


                      #11
                      valve cover gaskets and lower intake gasket for sure.....make sure to use felpro permadry gaskets

                      1986 lincoln towncar signature series. 5.0 HO with thumper performance ported e7 heads, 1.7 roller rockers, warm air intake, 65mm throttle body, 1/2" intake spacer, ported intakes, 3.73 rear with trac lock, 98-02 front brake conversion, 92-97 rear disc conversion, 1" rear swaybar, 1 3/16" front swaybar, 16" wheels and tires, loud ass stereo system, badass cb, best time to date 15.94 at 87 mph. lots of mods in the works 221.8 rwhp 278 rwt
                      2006 Lincoln Town Car Signature. Stock for now
                      1989 Ford F-250 4x4 much much more to come, sefi converted so far.
                      1986 Toyota pickup with LSC wheels and 225/60/16 tires.
                      2008 Hyundai Elantra future Revcon toad
                      1987 TriBurner and 1986 Alaska stokers keeping me warm. (and some pesky oil heat)

                      please be patient, rebuilding an empire!

                      Comment


                        #12
                        yup, they're spendy but they last. The cork ones do not. 40 bucks for the valve cover gaskets but you'll never have to touch it again.
                        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

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