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Coil Problem

OK vehicle is a 1977 f250 2wd with 351m 400 manual transmission. Have had the truck for about 2 months now. Ran fantastic from the first day. Timing is dead on engine is clean no leaks of anything Distributor, rotor, plug wires, plugs and alternator all replaced before the previous owner sold it to me. Said the carb needed rebuilt but I went and got a new 2 barrel carb to replace instead. OK the question is this: Almost 2 weeks ago started having odd problem where engine just quit. I feel the power kick down when the engine quits, of course as long as clutch is engaged engine continues to turn. push clutch in or apply brake no power. First happened it was about 4 days until it did it again. from then until a bout 3 days ago it just got worse.

Removed coil wire from coil and cranked it over. First couple of minutes of cranking no spark coming off coil. checked wires, found a loose wire adjusted it to make sure it connected had it cranked over coil started sparking. thought this fixed it? nooooo.

rewired the faulty wires to coil. wohoo! cranked over and... Spark. Thought it was fixed. Went for a drive. Died out check it on side of road: no spark let it set for a few seconds, miracles, it had spark again.

Friend told me bad coil. Sooo, put a new coil in. yay! spark. next morning hard time starting then went errand running, did pretty good for a few miles. Died again. Waited a few seconds cranked over. Got home checked through the lines found the wire from the key ignition marked "to starter relay do not cut or splice" was burning hot but melting through. plug wire on solenoid close to the neg side quit. rewired for now got it working by bypassing wire on ignition switch and looping around solenoid wire. still dies out once in a while not as often as before but now when it dies 1 of 2 things can get it restarted. A: while costing along shut off ignition wait a few seconds then turn ignition back on tadaa! engine starts right back up. B: coast with ignition on and coil starts throwing spark again.

Any one have any ideas? I'm thinking brain box and solenoid together, or brain box causing burn out on solenoid. I'm not a mechanic by any means I can swap parts out and tune up if shown how or have a manual but I can't diagnose so any help would be greatly appreciated.

Reply to
Dich and Cyn
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sorry this line should read; "checked through the lines found the wire from the key ignition

Reply to
Dich and Cyn

Sounds like the Duraspark module overheat problem which was common in them when new. If it is the original Duraspark module, I would be even more suspect of it. They would usually cool enough to restart in as little as 2-3 minutes. If that is it, it will become more aggravating as it continues to complete failure. For some reason they usually did not make it easy by just quitting.

Lugnut

Reply to
lugnut

I agree with lugnut but i'd check it's harness/connector first.

Reply to
samstone

Since you're not a mechanic, here's 2 cents worth of info: Be sure to ignore the solenoid completely. It has nothing whatsoever to do with the engine actually running.

It's not unusual for ignition modules to fail to work some of the time. That said, the ignition module is a good choice, but it's just a shot in the dark. If that doesn't fix it, you may also want to try the pickup in the distributor.

Reply to
Joe

I agree. Check the module for signs of leaking. When replacing, install the new unit so there is an air-gap between the mount area and the bottom of the unit. Also: check the wire terminals on the coil attachment. Look for the wire-end terminal being a proper fit/not smashed and having cut many strands of wire. I had similar problem and found the factory harnass terminals over-crimped which caused the voltage feed to the coil being delivered by only a few strands of wire. New terminals will cure this problem.

Dave S(Texas)

Reply to
putt

Duraspark module? as I said before I'm not a mechanic so I don't know what that is? Are you talking about the square silver colored box on the driver side firewall?

Reply to
Dich and Cyn

It is on the left fender, about 4x4 or a little bigger. They had problems with internal insulation breakdown. One of Ford's service checks was to use a 150 watt lamp on top of it for a while to heat it until it quit. It it didn't quit, the module was then subjected to additional testing found in the FSM. Most applicable Ford related manuals will have a series of electrical checks for it but, it will pass every one of them until it gets hot enough. Replacement modules are not that expensive these days. You will need to know the color of the grommet around the wire harness to get the correct one. Best bet it to simply take the old one with you. Modules run $70-100 new. Rebuilts and off brands are less.

Lugnut

Reply to
lugnut

Yes that is the module.

Reply to
putt

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