Flame-broiled mouse

Discussion in 'Troubleshooting & Diagnosis' started by Tphil413, Apr 16, 2008.

  1. Tphil413

    Tphil413 Veteran Member

    219
    0
    Jun 1, 2007
    San Francisco, CA
    Thanks for the reply...I am pretty inexperienced working with the wiring under the hood. Can you explain what you mean when you say to "check for continuity to ground." Exactly what does that mean and how do I check it? Do I need a special tool to do so?

    To recap the cause of the whole mess was a fuel leak that caused the engine to ignite in the area behind the carb and on down behind the block (passenger side). I did a quick check of the damage visually and replaced a few singed choke wires, but I thought the engine harness looked okay. Now that I took a closer look, I see that at one section looks somewhat melted. Couldn't really tell before because the guy who built her covered everything with lots of black tape. The melted spot is about level with the exhaust manifold and seems to be where the single wire from the solenoid (fusible link?) branches out into multiple wires (junction block?). Originally assumed I needed to replace the whole engine harness, but it was suggested I may only need to replace the fusible link. Thanks for your advice!
     
  2. EricsZ28

    EricsZ28 Veteran Member Lifetime Gold Member

    3,487
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    Feb 28, 2006
    Here and there...
    First off, I've been told that electrical tape does not belong under the hood of a car as it burns quite easily. While that was a First-gen Mustang forum (where I heard that) & I've not tested this theory, I don't intend to find out. Heat-shrink tubing (available at your local hardware store or Radioshak) is another option that I've been pursuing. It looks nice as well.

    Now, measuring continuity is simple, but it requires a multi-meter (you can get one for less than $5 at harbor freight tools or the like). You simply set the meter to the lowest setting for ohms (the horseshoe symbol) and then place one lead to the engine block/alternator bracket/somewhere with bare metal & the other lead on the 12V+ wire at the junction block you referenced.

    You should get no reading (infinite ohms). If you do get a reading of zero (or a few ohms depending on the meter) you have a short that needs to be found & addressed.

    Personally, if any wires look toasted I would cut them out, solder in a new wire, and seal it with heat shrink tube. I'm usually overly cautious though...
     
    Last edited: May 22, 2008
  3. EricsZ28

    EricsZ28 Veteran Member Lifetime Gold Member

    3,487
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    Feb 28, 2006
    Here and there...
    Don't feel bad, this is the same thing that is holding up my project. I'm chasing wiring gremlins from the previous owner. He removed all of my fusible links. Whoops. It's enough to make me pull out my remaining hair. :confused:
     
  4. Tphil413

    Tphil413 Veteran Member

    219
    0
    Jun 1, 2007
    San Francisco, CA
    Latest Update

    Thought I'd give everyone an update on the electrical issues and new info so far...

    Just to recap...current issues surfaced after I restored my interior, including installing new gauges and fixing several dash components. When I tried to start the car it start, kept trying when suddenly the engine caught fire at the rear of the manifold (passenger side) and fuel ran down the back of the block and tranny causing a fire under the car as well. I did a check of the damage visually and replaced a few singed choke wires, but I thought I was okay. Tried again and the car still wouldn't start. Not sure if the problem was caused by the fire or was part of the problem that casued it.

    Basically I have no spark at the plugs. I do have power everywhere else - at the starter, the coil and all accessories (radio, lights, choke, wipers, heater, tach, amp meter gauge). Initally the radio was not working, but I found a blown inline fuse (was working before I tried to start the car initially). So I think I can rule out a fusible link?

    Latest theories (1) a short in the wiring - something blew the radio fuse (attached to the ignition at the fuse box), not sure if this could have affected the distributor, (2) damaged tranny wiring - is there any wiring at the tranny that might be locking out the ignition? (3) whatever ignited the fuel leak short (arc) may have damaged the ignition wiring.

    Plan to do some continuity testing this weekend - just curious if you guys think I'm on the right track here.
     
  5. Tphil413

    Tphil413 Veteran Member

    219
    0
    Jun 1, 2007
    San Francisco, CA
    Anyone bother to read my update and respond? I'd love to get your feedback and any ideas? I know there are lots of guys in here who have an opinion...any help is appreciated. Thanks!
     
  6. Earlsfat

    Earlsfat Veteran Member Lifetime Gold Member

    1,504
    2
    Jun 14, 2006
    Whut?
    Don't know if this'll help... only glanced at the responses, etc, but... MY starting problem...

    1. Bad HEI unit. - Got new HEI at Advance for $30 or so, got cap and rotor while I was at it for another $30 or so.
    2. MSD box fried - Mailed back to MSD and they fixed it all up for about $45 SHIPPED (WooHooo!!!).

    Fixed them both... good as new.

    Lesson learned - disconnect battery charger before attempting to start, any surge will eat your MSD.

    I rewired mine soup-to-nuts, only thing reused was MSD box and column wiring harness - all new sockets, bulbs, etc. Into it for about $250 with connectors, shrinkwrap, testers, etc. Soldered and shirnkwrapped EVERYTHING. Tape has a tendency to melt and get the resin into the joint, acting as an insulator, NO tape in mine now! It was a true learning experience and after getting intimately familiar with wiring diagrams I realized just how messed up my maro was when I got it, and it really helped me understand how things work and where to look when stuff goes wrong. Took me about 2 months working on it for an hour a night here and there when my wife and kids would leave me alone, lol. All told probably a good weekend could have most of it done if I had to do it again, uninterrupted and if I had everything when I needed it. If yours is THAT bad, I'd say rewire it... mine got so I couldn't trust it to back out of the driveway and make it back into the garage... I didn't have a choice.

    Good luck.
     
  7. 79camaro2001

    79camaro2001 Veteran Member Lifetime Gold Member

    4,761
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    May 4, 2003
    Monroeville, PA
    Check all of your wires. pull off all of the tape and check them, if they are fine then clean them up zip tie them together and cover them with conduit.

    Also check your fusible link, if it's bad you can get a replacement at any electrical store worth their salt.

    Then make sure you are getting power to the distributor and coil if it's not a HEI unit. If it's a HEI unit make sure you are getting 12 volt or more at the power wire. If you do have power and it still don't spark for you, then your distributor needs to be tuned. replace the module, cap and rotor. Also go ahead and replace the wpark plug wires if you haven't done that yet.

    Also when you check for spark are you check at he distributor cap or at the plug end? If you are doing it at the plug end and it's the old one from the fire, it could be burnt somewhere.

    try these and get back with us on what you find. Also get rid of that glass filter, it's a fire waiting to happen as you found out, cause it leaks and it can break from vibration.
     
  8. 79camaro2001

    79camaro2001 Veteran Member Lifetime Gold Member

    4,761
    0
    May 4, 2003
    Monroeville, PA

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