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84 Grand Marquis with engine stutter while cruising

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    #31
    The remanufactured distributor has a new pickup coil in it, it's pretty easy to see it in there. I don't see any other options for distributors in my area except aftermarket ones from MSD, a reman Autoline from RockAuto, or a Napa brand reman. Everybody else sells the same Cardone ones.

    Back at it tonight, took off the second new TFI and put the old one on again and the sudden shut off went away. Still acts like it's misfiring randomly and the idle is a bit unstable when it's not acting like it's misfiring. Since it still acts the same (minus the sudden shut off) I'm guessing the new distributor is fine, and likely the old one was too.

    Jiggled and poked every wire I could get to, especially the coil wires, and nothing made a difference. Also sprayed around the vacuum lines and still didn't find any leaks. However, when I sprayed around what I believe to be the intake temperature sensor, the idle wavered exactly like it does on its own. Probably because the spray was making the sensor cold, but could that sensor be a possible problem?

    Originally posted by gadget73 View Post
    Maybe, but the last random "will not spark" thing that I saw was a broken connection right at the coil. The coils can go bad but shaking the wiring is cheaper.

    Only thing that might be clattering in the throttle body is the injectors. If the signal from the distributor to the ECM was getting interrupted for whatever reason you might get spastic injector pulse.
    That spastic injector pulse seems like exactly what it's doing. It clicks when the engine does its misbehaving and the injector spray also sputters. If it was purely ignition related, would it affect the injector spray? Or would they just keep spraying like normal through an ignition disturbance?

    Comment


      #32
      problems from the ignition pickup would affect injector spray. Injector pulse happens when the ECM sees a pulse from the pickup. That same pulse triggers the ignition module to make the coil do stuff. If the PIP signal were shorting to ground from damaged wiring it could kill both spark and fuel at the same time.

      The ECM also gets feedback from the coil to know when it fires. Thats the second wire on one side of the coil plug. It uses that to confirm that the spark advance that the ECM commanded actually happened. I don't think loss of that signal would mess with the injector pulse, but maybe?
      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


        #33
        +1 for bad pickup/distributor

        Your descriptions sound pretty much the same troubles I got the last half year with my 88 TC. The engine started and runs great until something warmed up then the misfire at idle beginn followed by misfires at some cruise conditions.
        I replaced the TPS, IAC, cleaned the EGR valve, new sparkplugs + wire and roter and cap, coil, cleaned the IAT, changed both water temp. sensors, rebuild the distributer with new motorcraft pickup and 3 different TFI modules (ranging from 20 to 70$), changed the caps inside the EEC-IV, changed the EEC... without a change.

        I solved the problem by replacing the distributor again to a new one! Maybe I did something wrong, when I rebuild the old distr. Since the new distr. the car runs great.

        Somewhere between the troubleshooting my car starts to eat the TFI modules. I solved the problem by rerouting the TFI to a cool spot added with a heat sink. There also exists an OEM heat sink bracket for relocated TFI modules.

        Good luck
        1988 Lincoln Town Car
        1975 Lincoln Continental Mark IV

        Comment


          #34
          Since I've wiggled and jiggled and yanked around all the wires and come up with nothing, and had two brand new TFIs go bad in just a day or three, I might be inclined to agree with getting a bad distributor out of the box. Except that it behaves exactly like it did with the original distributor. Like exactly to a T. At least when the two new TFIs went bad, they behaved differently, and they also behaved differently than the original TFI, which has its own mind.

          Is there a way to check or monitor the signal from the distributor pickup? I have a digital multimeter, an incandescent test light, and a timing light.

          Today I replaced the TFI again with a new Duralast version instead of the Motorcraft ones I'd been getting. Took it around the bock when it was pretty hot out, it started up and idled low, probably cause it was already almost 90 degrees from sitting in the sun. It idled perfectly smooth and drove perfectly smooth... half way around the block. The other half it was stuttering, but not bucking and misfiring. When I got back, the idle was much higher than when I started out, and it was a little uneven. So whatever is causing the stutters is also affecting the idle. Sometimes it'll start up and idle low, then after 30 seconds or so it'll raise the idle, or it'll raise it after I give it a little throttle. But that wasn't the case today when I first started it, it just ran perfect, for all of 5 minutes.

          Comment


            #35
            think you'd need a scope to read it properly.

            Does it behave itself better if you pull the SPOUT connector? It will lose power but if the ECM is doing stupid things to the timing advance it will buck and carry on. Might be the ECM is going stupid and commanding nonsense. May be time to re-cap the ECM. I found leaky capacitors in my slightly newer computer when i had it apart for unrelated reasons.

            almost sounds like it runs oK in open loop mode but once it warms up enough for closed loop it goes dumb.
            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


              #36
              I was thinking the same thing about open loop vs closed loop, however on my other cars it takes a lot longer than an 1/8th of a mile to go to closed loop mode. Then again they're OBD2, not OBD1 like this. I've also been wondering about the ECM, or something else heat related, but not engine heat related, since sometimes I can drive a short ways with it acting fine, have it start stuttering and go back home, then shut it off, sit for a few minutes, start it back up, and it'll drive another short ways acting fine. Though it doesn't always do that. Sometimes once it starts to stutter it does it every time, though maybe that's when it's been driven more, I'm not sure.

              Keep in mind that's talking about the suttering problem. The harsh misfire, bucking, stalling bit where it shuts off the injector spray is, I believe, a different problem. That seems to surround the TFI. The original TFI would have it doing that randomly. The first replacement TFI cured that for a several days until it decided to act up every time the engine started. The second TFI worked for a day until it started the same thing, but randomly, and would flat out shut the engine off with a no-spark condition every time, within 30 seconds to 5 minutes. This third new TFI hasn't had enough time to decide whether it's going to behave or not.

              Pulling the spout and trying to drive the car makes it feel like it has a lawnmower engine. I tried it once but it had such little power I was afraid to take it out on the road. I only made it maybe 300 feet and turned around so I don't know if it did anything for the stuttering. Pulling the spout made no difference to the misfiring/stalling/etc.

              Where is the ECM located, under the dash on the drivers side? Is it hard to remove it and inspect the caps inside? Also is there a way to tell when it goes into closed loop mode? And/or is there a way to keep it from going into closed loop mode without causing it to run worse? Maybe pulling the O2 sensor wire?

              Comment


                #37
                ECU is up under the dash on the driver's side. The connector is through the firewall inside the engine bay though, and is a little fun to get at. Swinging the speed control servo out of the way helps get back there a little easier.

                Re-capping is not horrible if you're comfortable working on a circuit board with a soldering iron. You just have to get the right uF rating from the old capacitors and a voltage rating the same or greater than the old ones. A ECU failure is usually the last thing I like to point at, but unfortunately capacitor failure is becoming a real thing on the ECUs as they age, and it can absolutely cause things to not work right.


                My Cars:
                -1964 Comet 202 (116K Miles) - Long Term Project
                -1986 Dodge D-150 Royale SE (112K Miles) - Slowly Getting Put Back Together
                -1987 Grand Marquis Colony Park LS (325K Miles) - April 2017 + September 2019 POTM Winner
                -1997 Grand Marquis LS (240K Miles) - The Daily Workhorse & March 2015 + January 2019 POTM Winner

                Comment


                  #38
                  Closed loop happens when the coolant temp sensor hits I think 160 degrees, however long that takes. Not impossible the ECT is full of it and causing the ECM to go to closed loop before it should. Easy enough to measure it

                  http://www.grandmarq.net/oldfuelinjection/page10.html

                  No ECT signal would keep it out of closed loop but but its one of the primary sensors for figuring out fuel so I don't quite know what it will do with no input from that. Probably over-fuel and that might cause different issues. Should not bother the ignition any though.

                  more off the wall thoughts, what sort of shape is the charging system in? Any light flickering or pulsing? bad rectifiers in the alternator will make for really dirty power and the electronics don't much care for that. Are the grounds reasonably clean? I *think* CFI cars have the computer sensor ground going to the back of one of the cylinder heads.

                  I'll admit at this point I'm just throwing things at the wall to see what sticks. The ECM is usually pretty reliable but 1984 was a long time ago.
                  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


                    #39
                    I know when I had a bad ECT, cold starts were fine, but hot starts and operating temp were a real battle to do anything. My ECT failed resistive and the computer thought it was 60F at all times. Cheap multimeter and checking that sensor and the air charge sensor are the easiest things to check.

                    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


                      #40
                      I see the ECU, it seems easy to remove, one bolt on the connector and one bolt holding it onto a bracket under the dash?

                      I measured the ECT when cold (70 degrees F ambient) and got a value of 15 to 19, which corresponds with about 100 degrees F, so a bit off? It was odd though, it would only give a reading right as the probes made contact with the sensor. Then it'd immediately go to zero as if I wasn't touching anything even though I was holding them firmly on the contacts. It did that repeatedly, and the value wasn't constant either, though it was within a constant range. When the ETC was hot after driving around the block and to the gas station it measured a solid 4.4 and it didn't go to zero. It read 4.4 for as long as I held the probes on the sensor this time, unlike when it was cold. So it appears to be working mostly correctly, at least when it's hot.

                      I took out the air intake temperature sensor and it was crudded up with black gunk, so I replaced it. It didn't make a difference.

                      The charging system works very well, lights are always bright and steady. I checked the grounds and they look clean as well.

                      Again driving it today, during the first 3 minutes it was smooth, then went to stuttering. I believe the problem exists under heavy load as well, it's just can't be felt then, because the transmission shifts noticeably harder, which means the throttle is open more, causing the transmission to shift harder via the TV rod being pushed down more. At least that's my theory. But it definitely shifts harder when it's stuttering.

                      While I was out with the car today, after it started its stuttering I stopped in the middle of the road, put it in park and shut the engine off (I live in the sticks). Waited maybe 15 seconds, started it back up, put it in drive and it drove smoothly again. Once it started stuttering again after a couple/few minutes I did the same thing, stopped in the road, into park, engine off, wait, start up, drive off, nice and smooth. This has to mean something. Maybe it takes the computer a couple minutes to go into closed loop, and when it does it starts relying on some sensor that's acting up? Maybe the closed loop section of the ECU is having issues? Maybe some electrical component starts to overheat and act up and by shutting off the engine with the key off it allows it to cool down enough to act right for another few minutes? I don't know, but I'm all ears if you guys have got some ideas.

                      Comment


                        #41
                        ECT sensor could be flaky when cold.

                        Last 84 I fooled with that did stuff like this, we chased all the usual stuff. Ended up being the nearly new spark plug wires. Stuck a used set of Ford Racing wires that i had pulled from my car on and it ran like a watch. That one would carry on mostly under load. Going up hills made it really unhappy.

                        I wouldn't completely rule out sloppy timing chain either. Pull the cap off and rock the crankshaft with a breaker bar. If you can move the crank any real amount before the rotor starts to move, thats not good. 84 has that plastic cam gear and they get really sloppy as the plastic wears down.

                        The ECM is in open loop until it sees ECT at 160 for some amount of time. Hot restarts will be open loop for a minute or so until it settles out.
                        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


                          #42
                          The spark plug wire bit strikes a cord because it wasn't doing the stuttering bit before I changed the TFI (the first time) and spark plug wires. At least not that I remember, and I think I'd remember this herky-jerky stuttering. I'd put the old wires back on but two of them came apart when I took them off, which is why I replaced them. Maybe I'll see about fixing those two and putting them back on. I don't understand how it could run perfect for about three minutes due to plug wires. Same for timing chain slop. Both seem like something that should affect the engine all of the time, not just after a couple minutes. I'll check them anyways though. I'll see about checking the ECU as well and those caps that leak on some people.

                          Comment


                            #43
                            What wires did you use? I seem to remember the problem ones were new Belden from Napa. Oddly I had the same ones on my black Mark VII and never had issues with them. Might be one of those spots that boring old Motorcraft wires are the answer. They're only like 30 bucks new from Rockauto.

                            Just did an ECM tonight, in 1990 at least its a pair of 47uf 16v and a 10uf 63v. It had the same leaky cap mine had. Not sure if the CFI computers are different, I expect they are just because why wouldn't they be? Fuzzy memory says Kishy posted pics of some CFI computer internals a few years ago.
                            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


                              #44
                              The wires I got are "Accel Custom Fit Super Stock" from Advanced Auto. The ones that were on it were "Accel Universal Fit Super Stock" which were much longer with straight boots instead of the angled boots. With cars like this I try to avoid buying things online because of the hassle of returns/warranty replacements. Getting the TFI replaced twice was cake at the parts store. Seems that my local Advanced Auto only carries Accel, MSD, Driveworks and Carquest. Autozone has the same Accel and MSD plus Bosch and Duralast.

                              It seems the CFI computers do have similar caps. I found a forum post elsewhere about an 84 Mustang LX 5.0 with factory CFI and they mentioned the caps in the ECU, couldn't find much info on whether they often leak or not.

                              As a side note, the car wouldn't start with the coolant temp sensor unplugged, and it wasn't a very happy camper after plugging it back in either.

                              Comment


                                #45
                                An SEFI car will start and run fair enough to drive with the ECT unplugged. I don’t know if CFI is suppose to or not, but I would suspect it should.

                                I wonder what would happen if you wired open the choke?

                                I have had those Accel Super Stock custom fit plug wires on my 88 for several years. No complaints.
                                1990 Country Squire - weekend cruiser, next project
                                1988 Crown Vic LTD Wagon - waiting in the wings

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