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Engine cranks over, but will not start(1985 Mercury Grand Marquis, CFI, 5.0 V8).

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    Engine cranks over, but will not start(1985 Mercury Grand Marquis, CFI, 5.0 V8).

    I have owned and driven this car from 2003 to 2014. It had always ran great with no problems whatsoever. In the fall of 2014, just before I put the car up for winter storage, I noticed it was loosing power and I had a couple times where it took a long time to get it started. In the spring of 2015, I started it up(same issue) then it was switching back and forth between running really rough with the loss of power and then smooth. Then it stalled on me and I have not been able to start it since. Here is a list things I have done, replaced and checked.

    - It did have spark.

    - Fuel pump comes on, I also checked at the throttle body for fuel pressure and it had fuel pressure. I even used some starter fluid just to be sure and that didn't help.

    - I replaced the ignition module on the distributor.

    - I put in a new oxygen sensor.

    - New ignition switch.

    - New spark plugs and wires

    Any suggestions on what route to next are appreciated.
    Last edited by Mercuryman; 12-31-2019, 06:58 PM.

    #2
    if its got fuel and spark it should run. Does it sound like the engine is spinning over with no resistance? If so, thats a sign the timing chain has jumped and that ain't good. The 85 and older models have plastic teeth on the cam gear and its prone to failure.
    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


      #3
      Yeah, that's what I was thinking. It sounds normal when cranking. I was wondering in the back of my mind if it was the timing chain, but hoping it wasn't that. Wow, plastic teeth lol. I wonder what year they started that? Is there way to check if the chain has jumped without pulling off the timing cover?

      Thanks

      Comment


        #4
        Take the distributor cap off bump the engine to TDC the rotor should point to no#1 spark plug wire keep doing this and count how many towers off from no#1 spark plug wire, if you are off each time you have "jumped time" on the timeing chain.

        Comment


          #5
          Plastic teeth started in the 70s, mostly gone in 85 but they randomly show up later. 87's seem to have gotten the leftover stock. Supposed to be quieter, but I can honestly tell you I've never noticed timing chain noise on my cars with steel gears.


          ^^ and yeah thats the quick and easy way of telling if its jumped.

          does it have spark still when cranking? Is it nice strong blue-white spark that will jump an inch? If it won't do that, it won't actually fire the plug under compression. Check at the spark plug end of the wire too. I've had distributor caps lose the center button and once I had a rotor burn through between the end and the rotating contact. The spark was shooting through the rotor into the distributor shaft instead of getting to the spark plug. Spark at the coil, nothing at the plugs.
          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
            Steel teeth gears sound way better, for just the durability alone.

            Previously, I had used an inline spark tester. It did have spark when cranking.
            I will have to check the plug end of wires though. Any suggestions on what to use, when testing to see if the spark will jump an inch?

            Comment


              #7
              I stick a screwdriver in the plug wire end and just position it so there is about an inch between the screwdriver and the valve cover. Need to wedge the screwdriver under something so it stays put. Thumb width is close enough to an inch.
              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


                #8
                I checked for spark at the spark plug end of the wires and it does have spark that jumps an inch.
                If the timing chain did jump, is there enough clearance with the valves on the 302 V8 that the valves won't hit the pistons?
                I know on some of the modern smaller engines there isn't enough clearance so the valves end up hitting the pistons, but a lot of those use a timing belt instead of a chain.
                Also, is it doable to replace the timing chain with the engine still in the car?

                Comment


                  #9
                  nope. Pistons smash the valves if the chain hops. If that happens the engine will spin noticeably more easily than it should.

                  very possible to do the chain though. Basically a water pump job plus a few more bolts.
                  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


                    #10
                    So, if the timing chain did jump, there is probably damage to the valves and pistons, I am assuming? It probably wouldn't be worth replacing the chain, I am most likely looking at an engine rebuild or swapping in another engine if I understand correctly?

                    Comment


                      #11
                      possible. leakdown and compression tests would tell for sure. If you have compression on every plug of at least 90psi (preferably ~120psi), it should be able to run and the valves aren't dead.

                      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


                        #12
                        yeah, comp test will tell you. Or just roll the engine to TDC on #1 and see where the distributor points. If it lines up with where the #1 plug wire is, the chain didn't jump. If its 180 out, just roll the engine 1 more turn. If its somewhere other than 180 out, it jumped. There is a #1 tower on the cap, but its not impossible someone hopped the wires around to account for a distributor that wasn't dropped properly, so verify where that wire is.
                        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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