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    Cold start; hot no start?

    I want to get some opinions on what's going on with my ' 87 grand marquis. So here's the spill; the car starts fine cold and holds idle. Once it gets up to temperature and the thermostat opens up. If the car is turned off and started back up immediately after, it will turn over but not hold idle without giving it some gas. I'm under the suspicion it has something to do either with the evap canister system or the ignition module. What do you think? Thanks all for the suggestion!
    @Ryan.Madison68

    #2
    Have you tested your coolant temp sensor? It could be as simple as that.


    Sent from my iPhone using Tapatalk

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      #3
      Coolant temp sensor, or possibly the IAC getting stuck would be my guess too. If it was ignition, giving it some throttle wouldn't help.
      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


        #4
        Thanks guys. I'll look into replacing the coolant temp sensor. It seems like most likely place. Is it in front of the motor near the rotor cap?
        @Ryan.Madison68

        Comment


          #5
          It will be on the passengers side of the motor. near the front on a pipe coming up and out of the lower intake. Two wire plug connected to it.

          When ordering dont mistake it for the one that is on the drivers side directly into the lower intake manifold. That is the one that goes directly to the replace engine light on your dash.
          ~David~

          My 1987 Crown Victoria Coupe: The Brown Blob
          My 2004 Mercedes Benz E320:The Benz

          Originally posted by ootdega
          My life is a long series of "nevermind" and "I guess not."

          Originally posted by DerekTheGreat
          But, that's just coming from me, this site's biggest pessimist. Best of luck

          Originally posted by gadget73
          my car starts and it has AC. Yours doesn't start and it has no AC. Seems obvious to me.




          Comment


            #6
            I found this unplugged. Where does it connect to? Thanks 87GTVic

            @Ryan.Madison68

            Comment


              #7
              Looks like the plug for the replace engine coolant sensor just to the 2 o'clock on your circled portion.
              ~David~

              My 1987 Crown Victoria Coupe: The Brown Blob
              My 2004 Mercedes Benz E320:The Benz

              Originally posted by ootdega
              My life is a long series of "nevermind" and "I guess not."

              Originally posted by DerekTheGreat
              But, that's just coming from me, this site's biggest pessimist. Best of luck

              Originally posted by gadget73
              my car starts and it has AC. Yours doesn't start and it has no AC. Seems obvious to me.




              Comment


                #8
                Okay. Does it connect on the metal stud right next to it on the valve cover? I tried to plug it back and it didn't fit.
                @Ryan.Madison68

                Comment


                  #9
                  If you still have the factory coolant temp sensor for the replace engine light it would fit right over the stud out of the unit.

                  If your factory coolant temp sensor for the replace engine light was removed and an after market coolant temperature gauge was put into its place you wont have a place for the wire.



                  I circled the sensor in yellow.
                  Attached Files
                  ~David~

                  My 1987 Crown Victoria Coupe: The Brown Blob
                  My 2004 Mercedes Benz E320:The Benz

                  Originally posted by ootdega
                  My life is a long series of "nevermind" and "I guess not."

                  Originally posted by DerekTheGreat
                  But, that's just coming from me, this site's biggest pessimist. Best of luck

                  Originally posted by gadget73
                  my car starts and it has AC. Yours doesn't start and it has no AC. Seems obvious to me.




                  Comment


                    #10
                    That makes sense. Thanks!
                    @Ryan.Madison68

                    Comment


                      #11
                      I swapped the coolant temp sensor, and it still is having trouble holding idle after a hot start. Any other suggestions? The IAC was recently replaced as well.
                      @Ryan.Madison68

                      Comment


                        #12
                        Sounds like you’ve covered the typical problem areas.

                        Won’t hurt to set the base idle just in case someone before has screwed with it: https://www.muscularmustangs.com/idlereset.php

                        Won’t hurt to check codes. If you don’t have a reader: http://www.fuelinjectedford.com/page13.html note that you don’t have a check engine light so you will need to use the test light or voltmeter.

                        Vacuum leaks also do some weird things to these cars. Check those out.
                        1990 Country Squire - weekend cruiser, next project
                        1988 Crown Vic LTD Wagon - waiting in the wings

                        GMN Box Panther History
                        Box Panther Horsepower and Torque Ratings
                        Box Panther Production Numbers

                        Comment


                          #13
                          There is also an air temperature sensor. #5 intake runner, driver's side, looks just about like the coolant sensor.

                          Is the IAC a Motorcraft part? Some of the aftermarket ones don't seem to work right.
                          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


                            #14
                            Thanks for the tips, guys. I'll look into setting the base idle first since it seems pretty easy to do. I haven't been able to find the air temperature sensor. Anyone want to snap a shot of its location for me? I would greatly appreciate it.
                            @Ryan.Madison68

                            Comment


                              #15
                              Lower intake plenum... driver side of engine between the front 2 cylinders.

                              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.

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