250cc buggy no spark
#3
06-13-2012, 11:30 PM
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The 2 plug 6 wire CDIs come in two different designs. One is powered off 12 volts DC, and the other is powered off a moderately high voltage AC which comes from the stator. Unfortunately there is no reliable way to tell the difference between the two by just looking at them. To be sure you need to use a meter to find out which you have:
1) Unplug the CDI, and turn on the ignition. Do not crank the starter motor. Use a meter to measure the *DC* voltage on the pin labeled "AC ignition power" in the wiring harness to both ground pins in the 4 pin CDI connector. If you measure 12 volts DC then you have a DC powered CDI.
2) If you don't measure 12 volts DC on the ignition power pin, then switch the meter over to measure AC volts on the 200 volt scale. While cranking the starter motor, measure the AC voltage on the "AC Ignition Power" pin to the the Ground pin. You should see 40 to 80 volts AC. If you measure AC voltage when the starter is turning then you have an AC powered CDI.
Using a meter is the only 100% reliable way to figure out if your CDI is AC or DC powered. But there are some clues you can use that are usually (but not always) correct:
A) DC CDIs tend to be a little larger than their AC powered counterpart. This is because the DC powered CDI needs a bunch more circuitry to convert the 12 volts DC to the moderately high voltage supply that all CDIs must have.
B) Most (but not all) DC powered quad ignition systems do not use the kill switch input pin. The CDI connector pin usually has no wire tied to it. AC powered quad ignition systems usually do use the kill switch input pin.
1) Unplug the CDI, and turn on the ignition. Do not crank the starter motor. Use a meter to measure the *DC* voltage on the pin labeled "AC ignition power" in the wiring harness to both ground pins in the 4 pin CDI connector. If you measure 12 volts DC then you have a DC powered CDI.
2) If you don't measure 12 volts DC on the ignition power pin, then switch the meter over to measure AC volts on the 200 volt scale. While cranking the starter motor, measure the AC voltage on the "AC Ignition Power" pin to the the Ground pin. You should see 40 to 80 volts AC. If you measure AC voltage when the starter is turning then you have an AC powered CDI.
Using a meter is the only 100% reliable way to figure out if your CDI is AC or DC powered. But there are some clues you can use that are usually (but not always) correct:
A) DC CDIs tend to be a little larger than their AC powered counterpart. This is because the DC powered CDI needs a bunch more circuitry to convert the 12 volts DC to the moderately high voltage supply that all CDIs must have.
B) Most (but not all) DC powered quad ignition systems do not use the kill switch input pin. The CDI connector pin usually has no wire tied to it. AC powered quad ignition systems usually do use the kill switch input pin.
#5
06-14-2012, 11:26 PM
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Here is the generic procedure for DC powered 6 pin CDIs:
To troubleshoot no spark problems on a 6 pin DC powered CDI it makes sense to start in the middle (the CDI), measure as much as we can and branch out from there. For the CDI to do its thing it needs power, a trigger pulse, and it must not be inhibited via the kill switch input pin.
1) Unplug the CDI. Turn the ignition switch on. Set all kill switches the the "run" position. In the wiring harness, look to see if you have a wire on the kill switch pin. If you do, measure the resistance of the kill switch pin to the ground pin on the 20K ohm scale. It should read infinite ohms (same as when the meter leads are hanging free and not touching anything). It should not read zero ohms (shorted).
2) Leave the CDI unplugged. Turn off the ignition switch. Set your meter to the lowest resistance scale you have (like 2 ohms or 20 ohms full scale). Measure the resistance of the "Ignition Coil" pin in the wiring harness to the ground pin. You should read something around 0.7 ohms (but not zero ohms). What do your measure?
3) Leave the CDI unplugged and the ignition switch off. Set your meter to the lowest resistance scale you have (like 2 ohms or 20 ohms full scale). Measure the resistance of the "Ground" pin in the wiring harness to the the negative battery terminal. You should read zero ohms. What do your measure?
4) Leave the CDI unplugged, and turn the ignition switch into the "on" position. Use a meter to measure the DC voltage on the pin labeled "AC ignition power" in the wiring harness to the ground wire on the 20 volt DC scale. You should read battery voltage (12 volts). What do you measure?
5) Leave the CDI unplugged. Use a meter to measure the resistance of the "Ignition Trigger Pulse" pin in the wiring harness to the ground wire on the 2K ohm scale. You should read approximately 150 ohms. What do you measure?
6) Set your meter down to the lowest scale you have for measuring AC volts. 2 volts would be ideal, but some meters don't go that low. In that case use the lowest scale you have. While cranking the engine, measure the voltage on the Ignition Trigger Pulse pin in the wiring harness to the ground pin. You should measure 0.2 to 0.5 volts AC. What do you measure?
7) Now plug the CDI back in. Measure the AC voltage on the Ignition Coil pin to the ground pin using the 200 volt scale. If you have to, use a sewing pin to poke through the wire insulation and then put the meter probe on the sewing pin. But don't hold your fingers on the connection during the next test - there may be high voltage here when the engine is turning. With the ignition on and all kill switches set to the "run" position, crank the starter motor. You should see voltages bouncing around at random values and the meter captures all or part of a spark event. What do you see?
1) Unplug the CDI. Turn the ignition switch on. Set all kill switches the the "run" position. In the wiring harness, look to see if you have a wire on the kill switch pin. If you do, measure the resistance of the kill switch pin to the ground pin on the 20K ohm scale. It should read infinite ohms (same as when the meter leads are hanging free and not touching anything). It should not read zero ohms (shorted).
2) Leave the CDI unplugged. Turn off the ignition switch. Set your meter to the lowest resistance scale you have (like 2 ohms or 20 ohms full scale). Measure the resistance of the "Ignition Coil" pin in the wiring harness to the ground pin. You should read something around 0.7 ohms (but not zero ohms). What do your measure?
3) Leave the CDI unplugged and the ignition switch off. Set your meter to the lowest resistance scale you have (like 2 ohms or 20 ohms full scale). Measure the resistance of the "Ground" pin in the wiring harness to the the negative battery terminal. You should read zero ohms. What do your measure?
4) Leave the CDI unplugged, and turn the ignition switch into the "on" position. Use a meter to measure the DC voltage on the pin labeled "AC ignition power" in the wiring harness to the ground wire on the 20 volt DC scale. You should read battery voltage (12 volts). What do you measure?
5) Leave the CDI unplugged. Use a meter to measure the resistance of the "Ignition Trigger Pulse" pin in the wiring harness to the ground wire on the 2K ohm scale. You should read approximately 150 ohms. What do you measure?
6) Set your meter down to the lowest scale you have for measuring AC volts. 2 volts would be ideal, but some meters don't go that low. In that case use the lowest scale you have. While cranking the engine, measure the voltage on the Ignition Trigger Pulse pin in the wiring harness to the ground pin. You should measure 0.2 to 0.5 volts AC. What do you measure?
7) Now plug the CDI back in. Measure the AC voltage on the Ignition Coil pin to the ground pin using the 200 volt scale. If you have to, use a sewing pin to poke through the wire insulation and then put the meter probe on the sewing pin. But don't hold your fingers on the connection during the next test - there may be high voltage here when the engine is turning. With the ignition on and all kill switches set to the "run" position, crank the starter motor. You should see voltages bouncing around at random values and the meter captures all or part of a spark event. What do you see?
#7
06-16-2012, 11:21 PM
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When I put together the generic test routine I put in a several redundant tests where I measure the same thing in two completely separate ways. I then compare the results to see if they match up. If they match I tend to believe the answers more. If they don't match then all the measured data falls into question. I do because very often people are new to this and make mistakes when measuring electronics. I need some way to separate simple measurement error from bonafide electrical problems.
Your data doesn't match at all and falls into the questionable area
.
First of all your data seems to be rounded to whole numbers. Why? Most meters have 4 digits of resolution. Thus on the 200 ohm scale you should have resolution down to 0.1 ohms, yet all your resistance readings are 10 times more crude. Data is king here. Always report readings with as much accuracy as you can.
On #2 you measured the resistance of the ignition coil to the ground pin at "0" ohms. Then on #3 you measured ground resistance to engine at "1" ohms. The ignition coil path from the CDI goes to the ignition coil to engine ground, and then from engne ground back to the CDI ground connector. But you measured the whole path having less resistance the part of the path. This is simply not possible. You did something wrong.
On #4 you reported 12 volts. I know your meter has better resolution than that. Yet you truncated the results. It is one thing to say that the extra resolution doesn't matter in this particular case, but I suspect you don't know that. Report all the digits in your readings, and be sure to use the right scale that gives you the best resolution possible.
The reading on #5 is wrong. If all your results up till now were credible this would be a big red flag. But your results are questionable to say the least, so I don't know what to think here. #6 is also wrong, and would follow if #5 is truely wrong - but I don't know at this point.
#7 is not making any sense either. Remember you reported that the ignition coil resistance from the CDI ignition coil pin to the ground pin to be zero ohms. But now you say that there is 2.7 or so volts across zero ohms. That would require the current through the coil (Ohm's law). Again this is simply not possible.
Please redo the tests again with a mindset to get the best resolution possible, and take the utmost care to get accurate and repeatable results.
Your data doesn't match at all and falls into the questionable area
. First of all your data seems to be rounded to whole numbers. Why? Most meters have 4 digits of resolution. Thus on the 200 ohm scale you should have resolution down to 0.1 ohms, yet all your resistance readings are 10 times more crude. Data is king here. Always report readings with as much accuracy as you can.
On #2 you measured the resistance of the ignition coil to the ground pin at "0" ohms. Then on #3 you measured ground resistance to engine at "1" ohms. The ignition coil path from the CDI goes to the ignition coil to engine ground, and then from engne ground back to the CDI ground connector. But you measured the whole path having less resistance the part of the path. This is simply not possible. You did something wrong.
On #4 you reported 12 volts. I know your meter has better resolution than that. Yet you truncated the results. It is one thing to say that the extra resolution doesn't matter in this particular case, but I suspect you don't know that. Report all the digits in your readings, and be sure to use the right scale that gives you the best resolution possible.
The reading on #5 is wrong. If all your results up till now were credible this would be a big red flag. But your results are questionable to say the least, so I don't know what to think here. #6 is also wrong, and would follow if #5 is truely wrong - but I don't know at this point.
#7 is not making any sense either. Remember you reported that the ignition coil resistance from the CDI ignition coil pin to the ground pin to be zero ohms. But now you say that there is 2.7 or so volts across zero ohms. That would require the current through the coil (Ohm's law). Again this is simply not possible.
Please redo the tests again with a mindset to get the best resolution possible, and take the utmost care to get accurate and repeatable results.
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#9
06-17-2012, 10:59 PM
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My comments in blue:
I'm wondering if you have two problems.
First things first: You have "no reading" for #5. "No resistance" could mean zero ohms, or it could mean infinite ohms depending on your viewpoint. Let's clear that up, but either way it is wrong. Look at the wire color that connects to this pin. Then go down to the stator connector between the stator and the wiring harness. Find the same color wire there (in the harness). Then disconnect the stator and measure the resistance of that same pin looking into the stator to the ground pin at the CDI.
When you were measuring the pin at the CDI in step #5 above you were measuring the trigger coil resistance (located inside the stator) to ground through the wiring harness. The next step is to bypass the wiring harness and measure it directly at stator. That way the problem can be localized to the wiring harness or the stator.
If you can't find the same color wire for the pin for test #5 down at the stator connectot then we have some more work to do... But most quads do connect directly.
The other thing I wonder is if your ignition coil is wired backwards. Do you have two small wires that connect up to the ignition coil, or just one? Ignore the high tension lead that goes off to the spark plug.
1. infinite [This is OK]
2. no reading [When you're using a meter there is no such thing as "no reading". Your meter is displaying something, correct? What does your meter say in the display, and what scale are you on?]
3. 2.3 [This is really high]
4. 12.95 with charger on, battery was low [This OK]
5. no reading [Again what does you meter read, and what scale are you on?]
6. no reading [Same as #5]
7. 3.2 not cranking 4.4 cranking [This still doesn't make any sense yet]
2. no reading [When you're using a meter there is no such thing as "no reading". Your meter is displaying something, correct? What does your meter say in the display, and what scale are you on?]
3. 2.3 [This is really high]
4. 12.95 with charger on, battery was low [This OK]
5. no reading [Again what does you meter read, and what scale are you on?]
6. no reading [Same as #5]
7. 3.2 not cranking 4.4 cranking [This still doesn't make any sense yet]
First things first: You have "no reading" for #5. "No resistance" could mean zero ohms, or it could mean infinite ohms depending on your viewpoint. Let's clear that up, but either way it is wrong. Look at the wire color that connects to this pin. Then go down to the stator connector between the stator and the wiring harness. Find the same color wire there (in the harness). Then disconnect the stator and measure the resistance of that same pin looking into the stator to the ground pin at the CDI.
When you were measuring the pin at the CDI in step #5 above you were measuring the trigger coil resistance (located inside the stator) to ground through the wiring harness. The next step is to bypass the wiring harness and measure it directly at stator. That way the problem can be localized to the wiring harness or the stator.
If you can't find the same color wire for the pin for test #5 down at the stator connectot then we have some more work to do... But most quads do connect directly.
The other thing I wonder is if your ignition coil is wired backwards. Do you have two small wires that connect up to the ignition coil, or just one? Ignore the high tension lead that goes off to the spark plug.
#10
06-18-2012, 05:53 PM
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no reading means its the same as if its not hooked up to anything so it reads 1 . on 200ohm scale
Tested ignition trigger pulse (step 5) at the stator harness and theres no reading.
I dont think the coil is wired backwards because i was driving it in the woods when it stopped running.
So because theres no reading from the stator does that mean its bad?
Tested ignition trigger pulse (step 5) at the stator harness and theres no reading.
I dont think the coil is wired backwards because i was driving it in the woods when it stopped running.
So because theres no reading from the stator does that mean its bad?