kerrzog
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I burned out 2 brand new cdi units on my 06 nytro almost right away. I replaced the stator,voltage regulator,checked all the wires for shorts and opens. It runs for a short period ,and as soon as you hit the throttle it cooks the cdi. First i thought it was voltage regular was going to an over volt (so did the local yamaha dealer) but it charges correctly and still burned the cdi for the second time. I have the factory manual,and the only thing it shows as a part of the ignition system is the TPS,but it also checks out .Anyone have this or heard of a problem like this,or any ideas. thanks kerrzog
Len Todd
TY 4 Stroke God
When you say CDI, I think are you referring to the Engine Control Unit (ECU). You are right. The old Tech Manuals used to call the ECUs CDIs. I just want to make sure we are on the same page.
If there is a short downstream of the ECU, the short could cause it to fail. Unfortunately, there are many circuits down stream of the ECU. I suspect chaffed wiring someplace is causing this. Typically chaffing occurs in the nose of the sled down by the ECU or around the steering post. But other locations on the sled have caused chaffing.
You could disconnect the connector from the ECU. Then measure each output contact for a very low resistance between the contact and ground. When you find one of these suspect conductors, trace it out and disconnect the component on the other end. If you still have a direct path to ground (i.e. very low path of resistance), then the wire must be shorting. By the way, there is one wire in the connector that should be ground. However, the rest of them should be open when the components on the other ends are disconnected.
Also, I have this nagging feeling that the wires from the stator could be shorting on the engine, where they come out of or inside the engine. We had several of these occurrences late last year on Nytros. The Stator output is a direct input to the ECU. Any problems there could cause intermittent potentially high current/low voltage spikes to the ECU. However, you would see this as a voltage drop (i.e. ~ 13.8+ VDC down to battery voltage 12VDC across the battery.) you would have to prepped and quick to see this as you went from Idle to Rev. But, this won't happen casue we do not want to fry another ECU. So, ...
It is time to inspect your wiring. Also, this assumes that you have verified that the ECU connector's contacts are not damaged and/or bent.
If there is a short downstream of the ECU, the short could cause it to fail. Unfortunately, there are many circuits down stream of the ECU. I suspect chaffed wiring someplace is causing this. Typically chaffing occurs in the nose of the sled down by the ECU or around the steering post. But other locations on the sled have caused chaffing.
You could disconnect the connector from the ECU. Then measure each output contact for a very low resistance between the contact and ground. When you find one of these suspect conductors, trace it out and disconnect the component on the other end. If you still have a direct path to ground (i.e. very low path of resistance), then the wire must be shorting. By the way, there is one wire in the connector that should be ground. However, the rest of them should be open when the components on the other ends are disconnected.
Also, I have this nagging feeling that the wires from the stator could be shorting on the engine, where they come out of or inside the engine. We had several of these occurrences late last year on Nytros. The Stator output is a direct input to the ECU. Any problems there could cause intermittent potentially high current/low voltage spikes to the ECU. However, you would see this as a voltage drop (i.e. ~ 13.8+ VDC down to battery voltage 12VDC across the battery.) you would have to prepped and quick to see this as you went from Idle to Rev. But, this won't happen casue we do not want to fry another ECU. So, ...
It is time to inspect your wiring. Also, this assumes that you have verified that the ECU connector's contacts are not damaged and/or bent.
kerrzog
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No its realy a ignitor unit (thats what the manual is calling it) 06 nytro with carburators. The only thing it is controling is spark,but the hand warmers,and signal (speedo cluster)only goes through. Dont know the voltage that runs through the speedo into the cdi unit,but typically is 5 volts on onboard computers. most input signals are resistend ground signals,and output signals are positive signals. did not know if there were any (tsb's) techinal service bultins on the ignition systems. tks kerrzog
Len Todd
TY 4 Stroke God
The ECU/CDI/Igniter controls more than Spark. It also controls the Hand Warmers, several relays, and provides several outputs to the gage and gage signal lamps, etc.. Any one of these wires could be chaffed and causing a short.
I am also wondering what voltage you had at idle, across the battery. Maybe the voltage regulator is not providing 12 - 14.2 VDC? Maybe it is passing the 24+ Volts on through to the ECU/CDI/Igniter.
But. I would still look for chaffed wires, first.
I am also wondering what voltage you had at idle, across the battery. Maybe the voltage regulator is not providing 12 - 14.2 VDC? Maybe it is passing the 24+ Volts on through to the ECU/CDI/Igniter.
But. I would still look for chaffed wires, first.
kerrzog
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I checked all the wiring Agian going into and out of the ECU for shorts and opens,and they all passed. like i said first, the stator assy,voltage regulator were all replaced,and still burned the ECU.The voltage at the battery, before the last melt down was 14.3 volts.This last time it ran for 20 min or so ,i thought i had it fixed ,but not. I am the second one trying to fix this sled,just tring to come up with what the previous owner/mechanic could have done ?? or if there is a common problem to this series of sleds. kerrzog 
Len Todd
TY 4 Stroke God
Not a common problem for ECUs to fry. But, if there is an intermittent short downstream of the ECU, you could have this problem. If the charging voltage is 14 VDC, it seems that the short would have to be after the ECU and before any fuses. Now, ...
Wire chaffing is a common cause of shorts. Chaffing is often intermittent. The most common places for chaffing is in the nose of the sled and at the handle bars. However, the crank position sensor wire chaffing has also been a problem from time to time on the 3-holers.
Wire chaffing is a common cause of shorts. Chaffing is often intermittent. The most common places for chaffing is in the nose of the sled and at the handle bars. However, the crank position sensor wire chaffing has also been a problem from time to time on the 3-holers.
kerrzog
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Took out the harness,cut it open and found no opens or shorts. Checked all input and outputs agian,and replaced the cdi,started and charged at 14.3 Volts. Ran for 2 min,shut off, burned up another one. I work in the auto industry,never had one like this EVER.The only thing it could be is a bad feed or something from the speedo? They fixed the problem today, they traded it in on a Ski Doo. Tks
Len Todd
TY 4 Stroke God
If it was charging O.K. and the harness was not shorting, then a component or connector must have been shorting to ground. Well anyway, the sled is no longer in your hands. Good luck with the Poo. Can't say that I blame 'em.
