Help DC CDI
#1
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Thanks,
Dan
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Last edited by dknuckles; 06-23-2011 at 08:47 AM. Reason: add picture
#2
Join Date: Dec 2008
Location: Tracy, California, USA
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Thanks,
Dan
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I posted a part of your private email below. I will embed my comments inside in blue...
Just an update i figured i would save you some typing i went off the post where you helped joe16066 so here are my readings.
1. Stator trigger (Green/White) ACV while cranking .330 cdi disconnected, .144 with it connected, .8 ohms connected to cdi, and disconnected 35 m ohms and progressively drops?
There is a conflict here... Measuring into the wiring harness with the CDI disconnected you should be seeing about 150 ohms or so (the resistance of the trigger pickup coil). You report "35 mOhms". What does that mean? Is it 35 MegaOhms (35,000,000 ohms), or 35 milliOhms (0.035 Ohms). Either way it is wrong. If it was 35 milliohms then it is shorted to ground and you couldn't have measured 330 millivots AC. And if it is 35 MegaOhms then you shouldn't measure 330 millivolts either since the pickup coil wiring is open.
These measurement need to be revisited because they don't add up.
On DC powered CDI it is common for one or more of the kill switches to be wired into the trigger circutry - shorting this line to ground to kill the engine. It is also common for some quads to put a switch in series with the trigger line, opening it up to kill the engine (by removing the trigger signal).
2. CDI is grounded .6 ohms.
This seems a little high, but probably OK
3. I have been leaving the kill switch wire disconnected but that has 323 K ohms. (red/blue)
323K ohms is the same as being open
4. The coil output wire has 3.1 ohms thats more than the spec you gave wich was .3 ohms this coil is an upgraded coil because the other two coils shorted and let the smoke out.
I've never seen a coil primary resistance that high, but recently there was another thread where the coil has 1.9 ohms and the quad eventually got running without changing the coil. Let's get the trigger signal discrepancies sorted out first, then come back to this if needed.
I measured the output to the coil from the cdi while cranking on ac volts and i have .001 vac. I am thinking i have yet another bad cdi and i am hoping that the coil i have will work being its the last one i have...
No voltage here could be due to a lack of a trigger signal, a bad CDI, and/or a bad coil. Your trigger signal measurements are definately bad, so let's start there...
1. Stator trigger (Green/White) ACV while cranking .330 cdi disconnected, .144 with it connected, .8 ohms connected to cdi, and disconnected 35 m ohms and progressively drops?
There is a conflict here... Measuring into the wiring harness with the CDI disconnected you should be seeing about 150 ohms or so (the resistance of the trigger pickup coil). You report "35 mOhms". What does that mean? Is it 35 MegaOhms (35,000,000 ohms), or 35 milliOhms (0.035 Ohms). Either way it is wrong. If it was 35 milliohms then it is shorted to ground and you couldn't have measured 330 millivots AC. And if it is 35 MegaOhms then you shouldn't measure 330 millivolts either since the pickup coil wiring is open.
These measurement need to be revisited because they don't add up.
On DC powered CDI it is common for one or more of the kill switches to be wired into the trigger circutry - shorting this line to ground to kill the engine. It is also common for some quads to put a switch in series with the trigger line, opening it up to kill the engine (by removing the trigger signal).
2. CDI is grounded .6 ohms.
This seems a little high, but probably OK
3. I have been leaving the kill switch wire disconnected but that has 323 K ohms. (red/blue)
323K ohms is the same as being open
4. The coil output wire has 3.1 ohms thats more than the spec you gave wich was .3 ohms this coil is an upgraded coil because the other two coils shorted and let the smoke out.
I've never seen a coil primary resistance that high, but recently there was another thread where the coil has 1.9 ohms and the quad eventually got running without changing the coil. Let's get the trigger signal discrepancies sorted out first, then come back to this if needed.
I measured the output to the coil from the cdi while cranking on ac volts and i have .001 vac. I am thinking i have yet another bad cdi and i am hoping that the coil i have will work being its the last one i have...
No voltage here could be due to a lack of a trigger signal, a bad CDI, and/or a bad coil. Your trigger signal measurements are definately bad, so let's start there...
I'm on vacation, and on the road. Whether or not I can post depends on the availability of internet access in the hotel room. If I don't respond in a timely manner it is because I can't
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#3
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Thank you for your reply especially on vacation i really do appreciate it! ok i went back through and found that the reading on the trigger wire was due to a bare slice contacting the frame slightly so now when i ohm it out it is reading as open OL but when i do an ac voltage reading disconnected i am getting .2-.3 vac? so if the reading is correct in ac how can that be possible that the trigger can read as open? i cut the harness all the way up to where it connects to the stator connectors and nothing is spliced in just runs straight from stator to cdi. i will see if i can find another coil for this model but from what i have been told the manufacturer stopped making parts for this model already and it is a 2010... maybe i will order a stator to if i am lucky enough to find one compatible. Again thank you so much for your help and dedication you have been the only one in over a month to actually try to help me. I hope you enjoy your vacation!
Dan
Dan
#4
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...i went back through and found that the reading on the trigger wire was due to a bare slice contacting the frame slightly so now when i ohm it out it is reading as open OL but when i do an ac voltage reading disconnected i am getting .2-.3 vac? so if the reading is correct in ac how can that be possible that the trigger can read as i went back through and found that the reading on the trigger wire was due to a bare slice contacting the frame slightly so now when i ohm it out open?.....
It may be that the AC signal that you're measuring is caused by just capacitive pickup from signals from adjacent wires in the wiring harness. This is further supported by the fact that you get a reduced voltage for the trigger signal with the CDI hooked up. Normally the output voltage of the trigger pickup coil is the same whether it is loaded by the 5K ohm input impedance to the CDI or not. But this wouldn't be true for pickup from adjacent wires.
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#5
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You should be at a five star! I figured it out! The pickup was reading open because it wasn't grounded:-) oddly enough it works opposite the way most others work? The kill switch is actually wired straight the the other lead off the coil and controls the ground for that? Before all this happend I actually had the kill switch disconnected and it ran fine? Although it was wired differently before... still not sure how it worked with the coil and trigger wire spliced together? Lynn I owe you a case of beer you saved the day! Actually the month! Thank you so much for all your help! Enjoy your vacation you deserve it!
Dan
Dan