I have a 1974 Duster with a 1972 340 c.i. engine. Ignition box is ORANGE. Went to a car show noticing amp gauge way over to +40. Volts at 14. Parking at show the car stalled and refused to re-start. Would only crank. Coil was RED hot! After allowing car to cool ( approx. 1 hour) it stared immediately. I replaced coil before leaving for home. Amps still near +40 , volts 13.5-14.0. How do I find the cause of the Amp draw, and am I about to burn up another coil? Afraid to get stranded again. Thanks for any advise on this.
DRAWING AMPS
- Thread starter ITSA34T
- Start date
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383Scampman
Well-Known Member
Recheck your grounds , then check your v.r.
1....First in this case I'd charge battery, if you have a maintainer, give it a charge with a "regular" charger, then use the maintainer for at least a day indicating it is "full" charged. DO THIS with at least one cable unhooked from the car, or out of the car
2...If you have an accessible battery and a hydrometer, check the cells for gravity, and "equal" between cells. If not, take it somewhere and have it tested. If it comes back "bad" I would get "a second opinion." In this case, as you described, the battery may well be "bad" such as 1 dead cell
3...AFTER you do 1, 2 above, put back in the car run it and warm it up. Check battery charging voltage, right at the battery with a good meter. give the engine some RPM to simulate "low to medium cruise" IE 35--40MPH. Exact not important. If it runs near 14 (warm should be 13.8--14.2) double check by turning on loads, headlights, heater blower, AC, whatever you have. It should be at least 13.5, the closer to 14 the better.
If you have a known good spare battery, you can temporarily bypass 1 and 2 and perform step 3 using your spare battery. Make sure, however, that it is "up."
4...If "3" is OK, measure "running" coil + voltage right at the coil. This will vary, but if you are using a factory type ECU setup and you should be running a ballast, this will run from 9--10 on up to maybe 12V with the battery at 14V. If you are running a heavier coil, follow manufacturer's instructions CAREFULLY. Some of the Accel and old Mallory coils actually used TWO ballasts in SERIES
2...If you have an accessible battery and a hydrometer, check the cells for gravity, and "equal" between cells. If not, take it somewhere and have it tested. If it comes back "bad" I would get "a second opinion." In this case, as you described, the battery may well be "bad" such as 1 dead cell
3...AFTER you do 1, 2 above, put back in the car run it and warm it up. Check battery charging voltage, right at the battery with a good meter. give the engine some RPM to simulate "low to medium cruise" IE 35--40MPH. Exact not important. If it runs near 14 (warm should be 13.8--14.2) double check by turning on loads, headlights, heater blower, AC, whatever you have. It should be at least 13.5, the closer to 14 the better.
If you have a known good spare battery, you can temporarily bypass 1 and 2 and perform step 3 using your spare battery. Make sure, however, that it is "up."
4...If "3" is OK, measure "running" coil + voltage right at the coil. This will vary, but if you are using a factory type ECU setup and you should be running a ballast, this will run from 9--10 on up to maybe 12V with the battery at 14V. If you are running a heavier coil, follow manufacturer's instructions CAREFULLY. Some of the Accel and old Mallory coils actually used TWO ballasts in SERIES
rustycowll69
Well-Known Member
I'm surprised you didn't see smoke. I'm thinking maybe you have a grounded field wire. Look between alt. and firewall. Examine wiring closely, maybe it melted going over the exhaust crossover in the intake manifold, and it is grounding out there.
pishta
I know I'm right....
If you got an old alternator, you may have a grounded field connector (but that would kick voltage up to 16+) but to draw those amps, you need almost a dead short through a high resistance device. Start unplugging fuses.
KitCarlson
Well-Known Member
Chasing wrong problem, based on voltage 13.5V to 14V, alternator, and regulator fine. However could be bad battery, short or other large load.
Hot coil and no start is likely ignition problem.
Possible problems with ignition:
Hot coil and no start is likely ignition problem.
Possible problems with ignition:
- Pick up to reluctor gap too large, often fails to trigger cranking when hot.
- Short to ground at coil (-), shorted tach wire?
- Ballast resistor wiring shorted together.
- My guess, both 1 and 3.
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They put a engine harness connector in these models. Its while plastic and near the rear of the right valve cover. Meltdowns resulting in variety of short circuits have occurred here. Full fielded alternator would provide too much power to everything, including the coil.
KitCarlson
Well-Known Member
I agree about shorts, but a full fielded alternator would put out more than 14V.
Something that can REALLY throw a guy for a loop is cross shorted wiring. This is when a heavy draw from a ground short, etc, heats up wire in the harness and welds two or more wires together. This can cause ....."interesting" results
Robj
Well-Known Member
I installed a reman alternator on my 70 Dart. I turned the key and saw smoke. Turns out both field spades were internally grounded. I'm thinking it was remanufactured to be used on a pre 70 car. I have a buddy with a 69 Valiant and he has a newer style case with the field spades grounded so it's not impossible. At any rate, my blue field wire melted all the way up to the ignition switch and the engine didn't start. Small wonder. You'll know if it's grounded trust me.
VERY common to see at least one grounded by the crap rebuilders. FIRST time I ran into this was middle seventies, we had sold a young man a reman for about a 72 Dodge pu. He came back "it was boiling the battery." Took me about 30 seconds to confirm HOW LUCKY HE HAD BEEN. One spade was grounded, he just happened to get the blue on the other one
So while it ran very high charging voltage, at least it did not burn down the wiring harness!!!!
Robj
Well-Known Member
It was my mistake for not checking. You can bet I will never make that mistake again.
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