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Thread: Tripminder Calculations

  1. #21
    I'm an air-conditioned gypsy gadget73's Avatar
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    Have a digital dash and a message center unit from an abandoned idea. They are chunky through-hole parts, no fuss to deal with. Just clean the boards of any leakage that may have occurred.

    leaky caps are just a general pestilence with old electronics. In the Mark VII, the EATC, overhead console, radio, tripminder, anti-slosh module, and the speedometer itself have all had failed caps. Caps in the Towncar's ECM barfed and leaked goo on the board.

    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 SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

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

  2. #22
    Carthago delenda est Lutrova's Avatar
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    I pulled the logic module earlier tonight, and it all came apart surprisingly easily. Unfortunately, nothing really jumps out as wrong to me.



    To my untrained eye, the capacitors all appear to be in good shape.





    It's a little hard to tell from the angle, but there's a tiny little chip with three wires running to it that was screwed to the bottom of the case with some thermal paste and a small wafer between it and the aluminum. There looks to be an identical chip mounted to the larger board, and judging by the second screw hole on the case it might have originally been mounted separately as well.



    I assume all the marshmallow-like stuff is some sort of factory-applied insulation, and not some catastrophic failure.

    This module did pass the quick test perfectly, except for some discrepancy between itself and the fuel gauge, which is known to be screwy. I do see some marks on the contact points with the wire connector, but I don't know if it's significant enough to cause any trouble.

    Now that I've got this thing cracked open, is there anything I should be doing while I'm in here?

  3. #23
    GMN Regular DerekTheGreat's Avatar
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    Wow, it looks brand new and quality on top of that, although I was only 16 days old when it was built.
    1985 LTD Crown Victoria - SOLD
    1988 Town Car Signature - Current Party Barge

  4. #24
    GMN Regular slack's Avatar
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    I believe the 3 prong chip with the thermal paste is a voltage regulator.


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

  5. #25
    I'm an air-conditioned gypsy gadget73's Avatar
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    yeah, voltage regulator.

    The white rubbery crap is basically like RTV gasket maker, just a slightly different compound that doesn't have acid to rot electronics. This one looks a lot different inside than the unit I have hanging around, but I think that one came out of an 82. That one was chock full of parts, this one is much more sealed, probably more reliable honestly.

    Any evidence of leakage around the 3 caps on the board? The tubular things with wires sticking out of each end. usually when they get real bad it will start to ooze out of the rubber sealed end. More typically its the small ones that go bad 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 SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

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

  6. #26
    Carthago delenda est Lutrova's Avatar
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    I was not quite seven years away from being born when this thing was made.

    There are a lot of Ford part numbers on this thing, and it appears they were making a lot of changes over the years. Maybe half of the little doodads attached to the boards have E0 numbers, a couple have E1s, and the rest are E6s. The pictures I posted may not be quite large enough, but there are little Motorola logos on some of the black rectangular bits.

    The case is certainly robust, but there are two large openings on the bottom. When I was removing the connectors with it still mounted under the dash, I could see right in between the boards to some of the capacitors. So the whole works have been exposed to air and whatever moisture was in it, but I guess dust wasn't able to settle inside.

    Capacitors all look solid. I can't see any deformations on the three big ones, or any of the smaller caps or diodes. All the circuitry looks to be intact, too, although the board with the most junk on it is bowed slightly.

    I think I'll just clean up the case, apply new thermal paste to the voltage regulator, and put it all back together. I'm sure I could analyze it more with a multimeter, but I don't know what I'm doing so I doubt I'd find anything useful.

  7. #27
    Carthago delenda est Lutrova's Avatar
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    Message center logic module is back in the car, and after running the self test it appears to be as functional as it was before. The display still cuts in and out occasionally, or shows only a fully bright single character, but this now seems more like a display module problem. I wouldn't be surprised if that part had bad capacitors, but as I've mentioned before, disassembling it non-destructively seems to be impossible.

    Back at the fuel gauge, I've started running down the diagnostic test for erratic readings. The ground in the trunk is good. 0.3 Ohms between it and sheet metal at the sender connector. But after bypassing the sender with two wires, one 10 ohms and the other 72, both had the gauge reading empty. I tried connecting a spare level sender before plugging the one in the tank back in. Both were also reading empty at the gauge. So now my erratic fuel level has turned into an always empty, which at least is still the same diagnostic test. The only thing I changed was swapping out the two ground screws under the instrument panel, one of which is probably for the digital instrument panels. Not sure how that would impact my fuel reading, though.

    So now that I've apparently ruled out the sender and the trunk ground, the next step is to pull the instrument panel and check the wire coming up from the fuel tank. I'd been banking on this being the problem, but after seeing the state of the message center module and other connectors under the dash, I'm not expecting to find any trouble. If that wire checks out, then the final step is to check voltage on the back of the fuel gauge. If it's at least 10 volts, then the gauge is bad. If it's not, then the shop manual wants me to correct the power circuit, however that might be accomplished.

  8. #28
    Still Wrenchin'! friskyfrankie's Avatar
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    Quote Originally Posted by Lutrova View Post
    Message center logic module is back in the car, and after running the self test it appears to be as functional as it was before. The display still cuts in and out occasionally, or shows only a fully bright single character, but this now seems more like a display module problem. I wouldn't be surprised if that part had bad capacitors, but as I've mentioned before, disassembling it non-destructively seems to be impossible.

    Back at the fuel gauge, I've started running down the diagnostic test for erratic readings. The ground in the trunk is good. 0.3 Ohms between it and sheet metal at the sender connector. But after bypassing the sender with two wires, one 10 ohms and the other 72, both had the gauge reading empty. I tried connecting a spare level sender before plugging the one in the tank back in. Both were also reading empty at the gauge. So now my erratic fuel level has turned into an always empty, which at least is still the same diagnostic test. The only thing I changed was swapping out the two ground screws under the instrument panel, one of which is probably for the digital instrument panels. Not sure how that would impact my fuel reading, though.

    So now that I've apparently ruled out the sender and the trunk ground, the next step is to pull the instrument panel and check the wire coming up from the fuel tank. I'd been banking on this being the problem, but after seeing the state of the message center module and other connectors under the dash, I'm not expecting to find any trouble. If that wire checks out, then the final step is to check voltage on the back of the fuel gauge. If it's at least 10 volts, then the gauge is bad. If it's not, then the shop manual wants me to correct the power circuit, however that might be accomplished.
    Sounds crazy but is your battery really strong? I have seen many electrical issues caused by a weak battery. My friend's '96 CV, with digital dash, was showing "CO" and other erratic readings until we recently swapped out the old battery for a brand new one. So far (over a month) the erratic reading disappeared and all is good. Like I said, crazy but one never knows - does one?
    What I Own: 1993 Mercury Grand Marquis GS
    What I Help Maintain: 1996 CV / 1988 CV / 1988 Tempo

  9. #29
    Carthago delenda est Lutrova's Avatar
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    I just replaced the battery a month or two ago, so it's brand new. And with the new battery I was still getting the erratic fuel level. The only things I think I changed before getting this always empty reading was pulling and reinstalling the message center module, and swapping out the two ground screws under the center of the dash.

    I suppose if the gauge is the issue then giving it a once over for capacitors and such wouldn't be too bad, but the shop manual expects you to just throw out the old one, so I'd be going in blind.

  10. #30
    Carthago delenda est Lutrova's Avatar
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    It's been awhile, but I've continued to plug away at the fuel gauge in my spare time. I have a spare digital fuel gauge, the original from my car, which I decided to take apart to see if any obvious failure jumped out at me.





    The assembly consists of two boards held in place in a plastic housing, secured by four screws and a bit of glue. The top board has the VFD mounted to it, while the lower board has most of the capacitors and other electronic doodads. The lower board has a part number E4VF-14A608-DA, which is the same part number Ford gave to anti-slosh modules for analog gauges.





    There are five terminals on the back of the gauge. All but the ground are connected through the printed circuit that also serves the speedometer and turn signal/high beam lights. Fuel signal is obviously the signal from the level sender in the tank. Message Center must pass this information on to the message center logic module for its distance to empty calculation. Illumination, I believe, goes to the headlamp switch to control dimming of the VFD. I don't quite understand what the Ignition terminal is for, unless it's the power supply.

    None of this information really gets me any closer to solving my erratic fuel level reading, but I figured the pictures might interest some. The circuit boards appear to be easily serviceable if you know what you're doing. That said, nothing looked like it had blown up or was covered in gunk. This fuel gauge had the same problem that I'm still facing after swapping it out for another, so either both gauges failed in the same way or my fault lies somewhere else in the system.

  11. #31
    Carthago delenda est Lutrova's Avatar
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    In other news, I've completed the shop manual diagnostic test for erratic fuel level, and while I know more than when I started, I still can't say I've found a smoking gun.

    For reference, this is the diagnostic test:



    So in order, this is what I've found so far.

    B1 - Trunk Ground: The ground in the trunk is secure, with 0 ohms between the ground connector at the level sender and sheet metal. Sender connector terminals are free of corrosion.

    B2, B3 - Resistor Wire Bypass: Jumping the sender connector with 10 and 72 ohm wires both displayed empty readings at the fuel gauge, which suggests the fault is not with the level sender.

    B4, B5 - Fuel Wire: From the instrument cluster connector, fuel wire reads open (>20k ohms) when disconnected at level sender and 0.4 ohms (<3 ohms) when jumped at sender connector. The fuel wire and the intermediate connection don't appear to be bad.

    B6 - Gauge Voltage: Fuel gauge has 12.12v (>10v) between ignition and ground terminals, which is a pass.

    Having arrived at the end of the test, the manual suggests the fuel gauge should be replaced. Or the 'fuel gauge ground circuit A7 bus bar' could need servicing, whatever that is. I guess I didn't really investigate step B0, as the level reading varies regardless of other electrical loads in the car. Just swapping out the fuel gauge is a bit of a bummer, since these things are so hard to come by and I seem to have two that look to be in great shape but are apparently bad.

  12. #32
    I'm an air-conditioned gypsy gadget73's Avatar
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    I think the buss bar is the big multi-tab thing under the dash near the gas pedal where a bunch of things plug in.

    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 SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

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

  13. #33
    Carthago delenda est Lutrova's Avatar
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    The vertical metal piece that a couple of grounds and the message center logic module bolt to? I think it might also be a support piece for the whole instrument panel? If it were to need service, the way to test it would be to touch a multimeter at one end and the other at some known good ground and check for no resistance?

  14. #34
    I'm an air-conditioned gypsy gadget73's Avatar
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    I believe thats the one yes. Only thing I would really imagine needing to do is unplug and re-plug each of those grounds. If something were crusty you'd find it with just a visual inspection of each connection. If nothing is really bad, just re-seating everything ought to be enough to sort out any questionable connections.

    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 SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

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

  15. #35
    Carthago delenda est Lutrova's Avatar
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    Yeah, nothing so far has looked crusty at any point in the system. Connectors, grounds, circuit boards, all clean as a whistle. I suppose all the leaves is some internal fault in the fuel gauge. And if the analog anti-slosh modules routinely go bad, then that's probably what happened here, except there's no simple way to bypass it.

    If I were more electronically-adept, I think it'd be possible to rig up and arduino to replace the main circuit board for the gauge. The VFD looks to be self-contained on its own board, and the external connections are just five wires. I'm sure for someone who has some experience with these things, it wouldn't be a very difficult project.

    One other thought, I've noticed the gauge will sometimes show one reading when first turning on the car, and then something wildly different after starting the engine. Similar behavior happens with my aftermarket radio, which will retain memory of its settings between turning off the car and setting it back to On or Accessory, but once I start the engine the radio resets itself. Is it possible there's some power surge or other funkiness that's throwing off the fuel gauge at ignition? How would you go about looking into that?

  16. #36
    I'm an air-conditioned gypsy gadget73's Avatar
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    cranking voltage will be low thanks to starter load, but most of those circuits should be turned off when cranking anyway. The start circuit typically powers just the starter, ignition, and EFI systems. Everything else drops out both to help unload the battery and to save it from funky voltages. If yours doesn't, maybe thats the real problem.

    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 SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

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

  17. #37
    Carthago delenda est Lutrova's Avatar
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    This cutoff is done at the starter solenoid? I assume that would be the place to test for a fault like this? Or maybe watching voltage on the terminals at the back of the fuel gauge?

    My electrical know-how is slowly growing, but still ends at tests described in the shop manual.

  18. #38
    I'm an air-conditioned gypsy gadget73's Avatar
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    its in the ignition switch itself. Have to verify what contacts go dead when cranking. I'd probably just pop the small wire off the starter solenoid so you can hold it in crank mode as long as needed for testing. I forget what the EVTM calls them without looking but there is the group of stuff thats hot in accessory mode and in run, the group of stuff thats hot in run, and a few things that are hot in start.

    a funky switch might cause this to happen, or if someone has added aftermarket crap and connected things together that ought not be connected it may do it. remote start, alarms, that sort of BS tends to tap into these circuits.

    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 SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

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

  19. #39
    Carthago delenda est Lutrova's Avatar
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    No evidence of aftermarket work in that realm. Someone butchered the radio connector and bypassed the amp, but that shouldn't come back to the ignition switch.

    Something is definitely funky in the dash wiring. I believe with cruise on, I can resume the set speed by activating the turn signal. I once assumed there was some short in the steering column, but having opened it up enough now, I'm afraid the issue probably lies deep within the dash and a proper inspection may require complete disassembly, maybe even removing the harness.

    I bet there's one little thing out of place in there that's causing all of these strange issues.

  20. #40
    I'm an air-conditioned gypsy gadget73's Avatar
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    radio does have key-on and steady-on power but if those were crossed nothing would turn off with the key ever.

    without looking at the cruise wiring I don't know for sure but there might be a shared ground in there somewhere between turn signals and the horn circuit. The cruise buttons power through the horn relay and it "sees" a different resistance to ground on each button. If that ground is funky it'll do odd things. Probably worth a look in your EVTM at the first couple pages where it shows the locations of all the grounds. That may show you the common link.

    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 SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

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

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