1978 Mad Max build: Beast of Burden

Discussion in 'The Stable' started by paul289, Jun 28, 2016.

  1. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Recheck your TV cable adjustment, just for grins and giggles. But a stuck 2-3 valve is possible.
     
  2. paul289

    paul289 In Fourth Gear

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    The TV pressure gauge line had popped out of the fitting in the transmission, so I plugged it. I don't wanna check it again, lol.

    The 2-3 shift valve, however, was quite sticky. A bit of 1500 grit sandpaper on the valve and in the valve bore and now it slides quite nicely. Just need new valve body gaskets and I'll be good to go.
     
  3. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    How the heck does a fitting pop out on only 35 PSI?
     
  4. paul289

    paul289 In Fourth Gear

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    Oh, it popped out when I went for a drive. It was one of those plastic ones with a compression fitting, and it probably popped out when I was near full throttle, which is around 70 psi.
     
  5. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Ah, that makes sense. It's why I always insist on brass fittings.
     
  6. paul289

    paul289 In Fourth Gear

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    Minor update: B&M is sending me a replacement pressure regulator valve which should show up on Thursday, and I did find that there's a 2-3 amp draw on the battery, but I haven't dug any deeper just yet. Might be kinda busy in the near future, so I'm not sure how much investigation I can do into that particular problem.
     
  7. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Wow, that much? It does sound like a partial short in the alternator, or the ignition electrical switch is coming apart. I had a '79 Malibu wagon that the switch was splitting apart and one of the wipers fell out, got caught between two contacts, which caused the battery to drain.
     
  8. paul289

    paul289 In Fourth Gear

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    I'm guessing it's a bad voltage regulator. The ignition system shouldn't be able to draw with the key off. I'll probably poke around in there tonight to see if swapping out the voltage regulator takes care of it. I do have one that was in use in my Mustang without issue.
     
  9. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Two things: one, undo the battery negative, and put a 12 volt test light in between the post and terminal; two, just unplug the regulator, then the charge cable connection at the alternator. If the light goes out when you unplug the regulator, replace the regulator. If it doesn't go out till the charge cable's removed, it's the alternator, likely a bad diode bridge.
     
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  10. paul289

    paul289 In Fourth Gear

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    Didn't have a test light handy, so I used my cheapo multimeter. With the voltage regulator plugged in, I was reading 2-3 amps between the ground cable and the negative battery post. With the regulator unplugged, it was reading 0 amps. The second regulator, which apparently was the original one, read 1-1.5 amps, so they're both bad, I guess. Time to swing by the parts store and grab another one.
     
  11. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Well, frankly, you need to see which line it's drawing on; between the field (F) and stator (S) terminals, field is ignition-controlled, and stator is constant power (IIRC), but should not draw amperage with the field de-energized. So, you can remove each terminal, one at a time, and put your meter on-line with the connection, as you did at the battery. Because power at the field may be an ignition switch shorted to power, and power at the stator may be a shorted alternator. Man, I haven't done this in such a long time, I've forgotten things! I hope I haven't tripped you up, that this gets done before you buy a new regulator.
     
  12. paul289

    paul289 In Fourth Gear

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    I do appreciate the info. Electrical systems are not my forte, so extra experience and insights are more than welcome.
     
  13. 65restomod

    65restomod In Overdrive BRONZE MEMBER

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    Just a suggestion: if it has been discussed already I apologize, have you looked at the cigarette lighter? It is "hot" all the time and if the element is shorted out it'll give you draw.
     
  14. paul289

    paul289 In Fourth Gear

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    It's worth checking, for sure.
     
  15. paul289

    paul289 In Fourth Gear

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    So, with the battery hooked up, there was a spark when I removed the field wire from the alternator, and it pulled 1.3 amps. So, guess I gotta check the ignition switch, then? Edit: But if it's the ignition switch, then it should also be powering the gauges, but those are off.
     
    Last edited: Feb 12, 2020
  16. 65restomod

    65restomod In Overdrive BRONZE MEMBER

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    Good place to start , just unplug the switch and see if there is still a draw.
    Next step would be a possible alt.? regulator is cheaper
     
  17. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    You have more than one point of electricity from an ignition switch, so one not fully disengaging could mean a bad switch or a short in the wiring. The switch has two positions where the ignition (and the field wire) should be OFF, and those are LOCK and OFF-UNLOCK. If you still have current flow with the switch unplugged I'd say the alternator is bad.
     
  18. burninbush

    burninbush In Maximum Overdrive

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    Re previous posts about drawing power -- I think you are seeing a bad alternator, likely a bad diode or two.
     
  19. paul289

    paul289 In Fourth Gear

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    I'll check to see which way power is flowing through the field terminal and check the ohms both directions. That should tell pretty definitively whether or not the alternator is at fault.
     
  20. paul289

    paul289 In Fourth Gear

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    Got the correct pressure regulator spring in last night. Glad I decided to wait to get this one, because the one I had in there apparently is totally wrong. (red is the one that was supposed to be there)
    [​IMG]
     

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