79 351/M JUST DIES ANYTIME.

Discussion in 'New Member Welcome Center' started by gregoc1, Nov 29, 2016.

  1. gregoc1

    gregoc1 In First Gear

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    HI. RANCHERO FOLKS. I HAVE A 79 ranchero 351/m 2v carb. It starts just fine but then randomely at different times just stops. What the . . . . Any help or troubleshooting suggestions would be just fine.
    THX.
     
  2. Jimbob

    Jimbob SITE SUPPORTER- SILVER GOLD MEMBER

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    Checked the wiring to the coil? and the rest of the ignition system?
     
  3. Rockdodger

    Rockdodger In Third Gear

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    The early electronic ignition modules from that era were notorious for failing. Instead of dying and staying dead they typically failed when hot and came back to life later. This made them nearly impossible to trouble-shoot. Once the aftermarket started making them the price of the modules went down. (I bought my last one for $16 at a Walmart. When they got that cheap, I always carried a spare.) There are 3 or 4 varieties of these modules from that era. The easiest way to tell is by the color of the grommet going into the module . (e.g. blue, yellow, etc.) They run about $40 now and you can get a lifetime guarantee with them.
     
  4. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    There are three components in Duraspark II that will fail in that manner (I bleed Ford blue and have encountered this on different Fords I've owned, as well as all the customer cars I've diagnosed/repaired over the years). The module is the most likely culprit, but the coil and the pickup coil both can fail in that way. To diagnose, plug in a known good module; if that doesn't cure it, for this step, you'll need another person. Have them behind the wheel. Take the coil wire off the distributor cap, stick a screwdriver in the end, and place it within a few millimeters of a good, unpainted ground. Have the person turn the key on, crank for a second, then turn it off. If it sparks like crazy (DO NOT hold on to the screwdriver!!!) the ignition is working at this time, but if it doesn't, watch the screwdriver closely; when the key is turned off, if the coil sparks once, the coil is good, and the pickup coil (also know as the distributor stator) is the bad part. If it doesn't spark on turning the ignition off, the coil is the bad part. So, welcome to the site! Go ahead and fill out your profile, and come join us in the deep end of the pool!
     
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  5. Cindy

    Cindy In Maximum Overdrive SILVER MEMBER

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    (yeah, where some of us are swimming olympic laps and some of us are dog paddling)<~~~me lol
     
  6. Mike

    Mike In Overdrive

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    Is the gas tank venting properly? When it dies again, go over and release the cap. Is there a rush of air?
     
  7. Jeff B

    Jeff B In Maximum Overdrive BRONZE MEMBER

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    When it cuts out, turn everything off and remove the air cleaner cover. Look down in the carb and move the throttle linkage between a half to a full stroke to wide open. You should see a shot of fuel squirt down the barrels of the carb. If you do, your a getting fuel and look for ignition or electrical issues. If you don't see fuel, there could be a problem from the fuel pump on back to the tank. Mine would crap out or stumble and I found out this was due to a collapsed screen or "sock" filter on the pick up inside the tank. In the old Fords and others, rust flakes or water or gum or other nasties can clog up your fuel lines. Good luck.
     
  8. ranchero888

    ranchero888 In First Gear

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    I had the same problem. I added a electric fuel pump mounted near the rear under the gas tank it seems to have solved the problem with my 79 Ranchero Gt .
     
  9. Tygr1

    Tygr1 In Fourth Gear SILVER MEMBER

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    I would bet on it being a fuel delivery problem.
     
  10. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    The way to tell which cause is at fault is this: when it dies, does it chuggle before dying (fuel), or is it like someone threw a switch and the engine stops immediately (ignition)?
     
  11. Tygr1

    Tygr1 In Fourth Gear SILVER MEMBER

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    So, have you had any luck yet?
     
  12. gregoc1

    gregoc1 In First Gear

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    Like someone turned the key off.
     
  13. gregoc1

    gregoc1 In First Gear

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    18
    Just checking all the replies. Someone mentioned the pickup coil in the distribuator. I think I'll Start there.
     
  14. gregoc1

    gregoc1 In First Gear

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    18
    I'll. Give it a try.
     
  15. gregoc1

    gregoc1 In First Gear

    Messages:
    18
    Checking the replies. I'll. Start with pick up coil as I've already replaced the main coil. thx for all the replies.
     
  16. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    If you have any questions, don"t hesitate to PM me.
     

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