mini quad no spark and no power to coil
Jul 14, 2010 | 12:13 AM
#1
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Weekend Warrior
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mini quad no spark and no power to coil
I have measured the timing trigger and AC power pins and got .3 VAC and 56VAC. NO kill switches are set. I have not measured the coil resistance yet. I am suspecting bad cdi as there is no voltage going to coil. Any thoughts?
Jul 15, 2010 | 12:02 AM
#2
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From: Tracy, California, USA
Ike,
Both these voltages (AC power and Timing Trigger) are OK.
You also need a ground to the CDI which you can verify with an ohm meter.
The ignition coil output in the CDI wiring harness connector should measure less than 1 ohm (but not zero ohms) to ground. In your PM to me you said you got 0.13 ohms at the coil, but the best place to measure it is at the CDI connector. That way you measure the coil prmary winding and all the wiring to and from the coil at the same time.
8000 ohms on the secondary is OK for a coil with a resistor cap. Sometimes these are removable - mine is not.
Your measurement of 14.7 volts DC on the coil primary pin is just plain wrong. I suspect measurement error since I cannot imagine any scenario that would put this sort of voltage on the coil. The voltage on this pin is very narrow AC voltage pulses peaking at a couple hundred volts with a damped ringing back and forth at 30,000 times per second, followed by comparitively long periods of nothing (zero volts) in between. You need an oscilloscope to measure this. If you put a typical meter on this pin (CDI is hooked up for this, and measured with the starter cranking the engine), you should see mostly zero readings with random numbers interspersed when the meter just happens to capture part (or all) of a high voltage pulse. This also depends a lot on the meter, but hopefully you have a generic meter that responds to weird waveforms like most other meters.
You said (via PM) that you had all your kill switches off. This isn't the same thing as measuring your kill switch pin on the CDI. If you have a bad kill switch or bad wiring you won't get spark. Measure your kill switch pin resistance to ground with all your kill switches off, and the ignition switch on. What do you measure? Then turn on a kill switch and do the same measurement. What do you get now? I can't tell you what you are supposed to get because you still haven't told me what kind of quad, engine size, etc.
. This is important info.
Lynn
Both these voltages (AC power and Timing Trigger) are OK.
You also need a ground to the CDI which you can verify with an ohm meter.
The ignition coil output in the CDI wiring harness connector should measure less than 1 ohm (but not zero ohms) to ground. In your PM to me you said you got 0.13 ohms at the coil, but the best place to measure it is at the CDI connector. That way you measure the coil prmary winding and all the wiring to and from the coil at the same time.
8000 ohms on the secondary is OK for a coil with a resistor cap. Sometimes these are removable - mine is not.
Your measurement of 14.7 volts DC on the coil primary pin is just plain wrong. I suspect measurement error since I cannot imagine any scenario that would put this sort of voltage on the coil. The voltage on this pin is very narrow AC voltage pulses peaking at a couple hundred volts with a damped ringing back and forth at 30,000 times per second, followed by comparitively long periods of nothing (zero volts) in between. You need an oscilloscope to measure this. If you put a typical meter on this pin (CDI is hooked up for this, and measured with the starter cranking the engine), you should see mostly zero readings with random numbers interspersed when the meter just happens to capture part (or all) of a high voltage pulse. This also depends a lot on the meter, but hopefully you have a generic meter that responds to weird waveforms like most other meters.
You said (via PM) that you had all your kill switches off. This isn't the same thing as measuring your kill switch pin on the CDI. If you have a bad kill switch or bad wiring you won't get spark. Measure your kill switch pin resistance to ground with all your kill switches off, and the ignition switch on. What do you measure? Then turn on a kill switch and do the same measurement. What do you get now? I can't tell you what you are supposed to get because you still haven't told me what kind of quad, engine size, etc.
. This is important info.Lynn
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