74 duster ,dies while driving

Hi,thanks for the reply.The 2 coils are new and capable of putting out 40,000 volts with spark tester attached.The wires are 4 mos. old and no misfire exists.I bought a set of accel wires which come 500 ohms per foot,creating better conductivity.I have a feeling that if this improves or corrects things that its just a bandaid covering another problem such as a high resistance wire or connection causing a current flow problem once the ignition is completed through the cap,rotor,wires and plugs to engine block ground.That may be why the voltage readings are correct because we are not reading current.Thanks,Paul  

I seem to remember getting about 10.5 or 11 volts on the on the ign. side of the ballast, and about 8v on the coil side. You will loose some voltage thru all that old wiring, bulkhead and ign. switch.

I think your 8v is OK. I still think your spark box is toast. They will not survive under load or high rpm like highway speeds when they are about to go.

When mine stalled on the highway after about 5 minutes and get towed home twice, mine would start right back up again because the spark box had a chance to cool down.

This was the last thing I checked because the box was new...should have been the first thing.

I would try one from another car, then if that works, get yourself a new chrome box.

Jim  

Thanks for the reply.When your car died was it a situation where you had no spark?Usually when ignition modules go bad  under hear they die and like you said they cool down then restart,but mine has coil spark and if module craps I would have a no spark condition.Pickup coil tells module when to trigger spark based on the position of the reluctor.Although anythings possible.I wish I had a car to swap out.I have a feeling taht since It improved with the last cap with brass inserts that I have a resistance problem causing poor current flow in the ign. circuit and by completing the circuit by plugging coil wire into cap this completes to ground through cap ,plug wires,plugs.Ill keep you posted.  

i have the same problem i havent figured it out yet but wen mine does it i noticed sumtimes there isnt any fuel in the fuel filter i have a clear glass one my problem started a couple weeks ago so i was thinking maybe the fuel pump  

Hi,When mine dies the fuel filter is about 1/5 full but has fuel in carb when pumping throttle.When car is running the fuel filter doesnt get much more than thatin filter.Can you see fuel in carb when pumping throttle?If not you definately have a pump issue.I am waiting on an ignition module to come in ,in case I have a current issue when coil wire is plugged into dist cap.I just replaced wires with accel low resistance wires and problem got worse probably due to higher current on an already hurting module.Plug wires are listed at 500 ohms per foot.Ill keep you posted once module is replaced.Paul  

hey, did you check the wiring between the control module and the dist?  a different wire feeds the coil, so it could be getting power without the dist being energized, my schematics and in the shop or I might be able to help further. If that was the case you could buy a 20 dollar conversion harness, rewire and everybody's happy.  But then I've been a body man for years and chances are good my controle module is fried.  

Paul, Replace the Ignition Coil,a defective ignition coil will start to cut out when it gets hot, and that can usually only take a few minutes. When the coil cuts out you can still have a spark at the coil but the spark is not large enough to jump the gap between the rotor and cap so you will not have a spark at the plugs. Now you mentioned by replacing the cap and rotor it can run longer, thats because of a new tighter gap the spark jumps between rotor and cap but as the coil loses spark it can no longer jump and it will eventually stall the engine. As the coil cools down it starts to work again until it heats up and cuts out again. Ive seen this ignition coil problem many times and it sounds exactly what you have described.

If you have replaced the ignition coil try a differnt one.

Let me know how you make out.  
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