amp meter bypass??

Discussion in '40- & 55-Series Tech' started by delmandi, Aug 16, 2012.

  1. delmandi

    delmandi

    Messages:
    144
    Location:
    Kerrville, TX/Houston, TX
    I wanted to install some aftermarket gauges since my temp and oil pressure dont work in the dash. I picked up a set of 3 from the local parts store, oil pressure works, temp works, volt meter works, but 40 wont start.

    Is this because I disconnected the amp meter?

    I am assuming so? Since I hooked it back up and starts like nothing happened.

    Can I bypass the amp meter some how?

    Is it necessary to have an amp meter? Will a volt meter be sufficient?

    I did a lot of researching on here and couldn't find anything pertaining to my situation. Thanks.
  2. Texican

    Texican s-Moderator

    Messages:
    5,623
    Location:
    Bonham Tx.
    tie the 2 wires together that used to go the the back of the amp meter.......current flows thru it like your water meter.........of course you might get busted if you bypass your water meter......
  3. delmandi

    delmandi

    Messages:
    144
    Location:
    Kerrville, TX/Houston, TX
    Thanks, I love your screen name! Thats what I tell people at work when they ask if I'm Mexican! hahaha

    On bypassing the amp meter, I though one was positive and one was negative? the back of the gauge is labeled such?

    The water meter isn't by passed it just doesn't work, I replaced the temp gauge that a PO has installed on the head.
  4. jimkyser

    jimkyser SILVER Star

    Messages:
    543
    Location:
    Chicago, IL
    You CAN bypass the ammeter. You'll need to either move one of the two wires on the back of the ammeter to the same stud as the other side or avoid all of that current going through the firewall twice and wire the alternator to the starter directly. Here is a web page that describes why this is a good idea and also how to make it work.

    http://madelectrical.com/electricaltech/amp-gauges.shtml
  5. delmandi

    delmandi

    Messages:
    144
    Location:
    Kerrville, TX/Houston, TX
    Great! thanks! I will do that tomorrow.
  6. bj40green

    bj40green Tssss, tssss

    Messages:
    2,564
    Location:
    Playas del Coco, Costa Rica
    There is no mention of your truck and year but I assume that we're talking about a FJ40 before '79 with a 30-0-30 Amp meter.
    In that case you can bypass the amp meter by bolting the two wires together and insulate them with tape.
    The advantage of this over bolting two wires on one stud is that you don't have to disconnect the battery when you take out your cluster.
    The polarity on the back of the meter is for negative (discharge) / positive (charging) indication.
    A volt meter will do the job.

    The OEM temp gauge works in combination with the fuel gauge.
    For more info on meters / gauges -► http://forum.ih8mud.com/40-55-series-tech/544543-clusters-gauges-odo-meters.html


    Rudi
    Last edited: Aug 16, 2012
  7. Texican

    Texican s-Moderator

    Messages:
    5,623
    Location:
    Bonham Tx.
    I was talkin about the water meter at your house..:confused:...it was an analogy, so's ya could understand........

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