What makes your CDI go bad?

[krusty_45]

I bought this superjet with no spark. Checked everything and it was within spec, so i replaced the CDI and ran great. Built a 61x 701, same electrical out of the 650. Took it out today to break it it, ran great most of the day i was toying around and all the sudden no more spark. Got it to the beach and sure enough no spark. I tested the start stop switch and im about to go make sure all the coil outputs are correct. Im hoping its something simple i have another CDI to swap out and i will bet thats the problem.

So my question, can not the right voltage/amperage output from the coils fry the cdi? I know its possible if you dont ground when doing a compression test but what the hell would make it just die when it was running so good?

I'll be back shortly, any help is appreciated because im going to powell for a week on monday and need the ski!

 

[MADMAT]

From what I understand (and it makes total sense to me based on how many desktop/workstation motherboards I replace for the same reason) the capacitors swell due to cranking with out the plugs attached.

The energy needs to go somewhere and if caps swell then the intermittent BS starts.

 

[cosander]

dielectric capacitors have a limited shelf life. cranking with no load could very well shorten the life of the caps. I've read somewhere that a coil that is intermittently bad will cause a cdi to go bad.

 

[krusty_45]

Sure enough it was the CDI.....:rocketwhore: The CDI it fried was a used one i bought somebody here on the X. It only had two rides on it since i put it in.... today being one of them. Who are the people that do the rev limit mods and stator rebuilds? I think i would like to call them and see what they have to say about my superjet eating CDI's for lunch..... they arent that cheap.

My Charge coil was putting out 33 volts. My pulse coil was putting out 4 volts. This is all at cranking speed, not running speed of course. Im wondering if at running speed the coils are putting out too much and frying the CDI's.

matt, that is a plausible idea. You fix computers for a living i take it?

Anybody else have any ideas to why my superjet likes CDI's so much?

 

[krusty_45]

I've read somewhere that a coil that is intermittently bad will cause a cdi to go bad.

As in when i tested the coil and one crank it said nothing for an output, then the next crank it showed voltage? I did that but i assumed it was because i wasnt getting a good connection with the ground on my multimeter leader.

 

[cosander]

As in when i tested the coil and one crank it said nothing for an output, then the next crank it showed voltage? I did that but i assumed it was because i wasnt getting a good connection with the ground on my multimeter leader.

probably a weak hand on the multimeter lead (scratch your way to metal) then:








1. check the AC output of the "charge" coil. Don't get confused with the term "charge" coil......this is what Yamaha calls it, as it "charges" the cdi capacitor. This coil can generate in excess of 500 volts!!
Dis- connect the brown / white trace wire and ground wire and connect the meter leads to these wires, and while cranking the engine, observe the reading. You should have 30 to 50 volts AC depending on how good a battery and starter you have.

2. Check the pulser coil output. It's job is to tell the cdi when to fire the energy stored in the capacitor. Dis- connect the white / red trace wire and connect the meter leads to this wire and the ground wire. You should get a pulsating 4 to 5 volts AC. (ps, an analog meter is best for this test)

3. If you are having problems with the battery not recharging, then dis- connect the two green wires and read the cranking voltage produced by the "lighting" coil. This coil's name is a throw back from the old enduro bike days, when the manufacturer would add a coil to the stator to operate head, brake and turn signal lights....without a battery, and later with. Anyway, you should see 6 to 10 volts or so here, again AC. This coil puts out close to 20+ volts AC, to be recitified to DC and regulated at 13.5 or so to recharge the battery. This coil is rated to generate up to about 2amps of charging current. This in mind, beware when running two bilge pumps.....a battery going bad (high internal resistance) and two bilge pumps running for a extending time is just enough to cook a lighting coil.

4. Ignition coil. Not many folks do not have a meter capable of resolving the almost dead short of the primary on this coil. But if you do, the resistance should be .078 to .106 DON'T forget to subtract the meter leads resistance by shorting together and subtracting, or adjusting the zero ohms pot, if you have it. Also, remove and insert the leads in the sockets to clean the connection.....I often see 1 ohm or more go down to .2 or .3 by performing this task.
NEXT, check the health of your spark plug wires, or high tension wires as the Brits like to say. The only way to test them properly is to remove the boots and get to the end of the wire. You can try jamming the point of the meter probes into the end, but due to the dirt and metal dust, it often does NOT give a solid connection / reading. If you have electrical contact cleaner, by all means spray with that first. You should read 3500 to 4700 ohms, or 3.5 to 4.7K ohms STEADY....while flexing the wires from end to end. If you get any fluctuations, they are bad...IE breaking up inside, turning to a high resistance powder of metal and rubber. I have seen bad plug wires cause problems with idle and low speed only, mid range only, and high speed only, and every combination thereof. Very strange !!!

If all these check out good, then I would swap the cdi with a known good unit....and known good means just what it says.....you have had it running in your boat, you removed it, and you put it away..The only other known good is a new unit. I have heard many a sad tale of days of trouble shooting with no luck, only to find out that the "known good" cdi your buddy gave or loaned you was not good after all.

Another interesting point is the "sparks when you let off the start button" syndrome. This always means on of two things......the cdi is bad, or the pulser coil is bad, or the wire from it to the e box is open.

Another good point to keep in mind: it is very possible to have two problems going on at once. One, like bad plug wires may have going on for a while, but no creating any major problems....the performance degrades so slowly you really don't notice it. Then, the charge coil insulation starts breaking down, or the connection from the winding to the terminal posts goes bad and starts arcing over. The two combined creat havoc, and can make diagnosis difficult.

After seeing so many stator coils have a good resistance, but test bad....I strongly advise against using resistance readings alone a gauge of health. Perform the cranking voltage output test!! Resistance readings are still useful for some work, so here they are for 61X and 62T:

61X: charge coil, brown / white trace to ground / black: 365 +- 10%

Pulser coil, white / red trace to ground / black: 12.6 to 15.4

62T: Charge coil, brown / white trace to ground / black: 497 to 608

Pulser coil, same as above

Lighting coil, green / green wires: 1.14 to 1.40 Since this coil is not grounded in any way to the stator frame, you can check this coil for leakage to ground (indicating bad insulation) by measuring between either green wire and ground with your meter set on the highest ohms scale, usually 20 to 40 meg ohms. If you get any reading, the coil is going bad.

There are other tests we perform to positively verify a coil's health, but the equipment is specialized and the proceedure is beyond the scope of this posting.

A note about the ignition coil: CDI ignition coils are much different than the coils in many cars, especially older cars. Those coils operate on the "collapsing magnetic field" principle to creat the high voltage. CDI ignition coils are in essence "step up transformers" simular to any any plug in wall transformer to operate various devices. The output is directly proportional to the input.

Another interesting proceedure you can do to gain more information about your coil's health.......hook your meter up to any coil, set it on the highest scale, and observe the reading. Leaving it there for an hour or more and come back and see what it reads. A lower reading or higher reading, or a reading that will not stabilize indicates a bad, or going bad coil. This may only work with better quality meters.

Some of this applies to Kawasaki too. If you want more info on Kawasaki, as well as Polaris, please contact me via e mail, NOT pm.

As most of you know, we can restore any stator and ignition coil to better than new condition. Please check our web site, or give us a call if you need more information.

cosander View Public Profile Send a private message to cosander Send email to cosander Find More Posts by cosander Add cosander to Your Contacts

 

[krusty_45]

My Charge coil was putting out 33 volts. My pulse coil was putting out 4 volts. QUOTE]

Yes i tested my coils already as stated above. I appreciate the voltage specs that you posted up, it helps alot.

BUT, i was reffering to my coil being bad/intermittent. What i ment to say is that i assumed it was a bad connection with my leads when i cranked it the first time and there was no voltage output. Then i scratched my ground for a good connection, cranked again and had voltage. Tried again just to be sure and had no voltage again. Assumed is was the ground again, scratched, cranked, and had voltage. It was an on and off thing.

Im going to take the ebox apart, again, and test the charge coil mulitple times in a row to make sure its not being intermittent.

Where did you read that a intermittent coil can make the CDI go bad?

 

[Crab]

If all these check out good, then I would swap the cdi with a known good unit....and known good means just what it says.....you have had it running in your boat, you removed it, and you put it away..The only other known good is a new unit. I have heard many a sad tale of days of trouble shooting with no luck, only to find out that the "known good" cdi your buddy gave or loaned you was not good after all.

Best info I have read in a while, my thoughts exactly.

 

[krusty_45]

I found the problem and fixed it already, IT WAS THE CDI. I want to know what makes them go bad. Like i said already my superjet has FRIED 2 OF THEM SINCE I BOUGHT IT ON ONLY THREE RIDES.

THE TITLE OF THE POST SHOULD BE THE SUBJECT!

So WHAT MAKES A CDI GO BAD?

 

[Chadillac]

probably a weak hand on the multimeter lead (scratch your way to metal) then:








1. check the AC output of the "charge" coil. Don't get confused with the term "charge" coil......this is what Yamaha calls it, as it "charges" the cdi capacitor. This coil can generate in excess of 500 volts!!
Dis- connect the brown / white trace wire and ground wire and connect the meter leads to these wires, and while cranking the engine, observe the reading. You should have 30 to 50 volts AC depending on how good a battery and starter you have.

2. Check the pulser coil output. It's job is to tell the cdi when to fire the energy stored in the capacitor. Dis- connect the white / red trace wire and connect the meter leads to this wire and the ground wire. You should get a pulsating 4 to 5 volts AC. (ps, an analog meter is best for this test)

3. If you are having problems with the battery not recharging, then dis- connect the two green wires and read the cranking voltage produced by the "lighting" coil. This coil's name is a throw back from the old enduro bike days, when the manufacturer would add a coil to the stator to operate head, brake and turn signal lights....without a battery, and later with. Anyway, you should see 6 to 10 volts or so here, again AC. This coil puts out close to 20+ volts AC, to be recitified to DC and regulated at 13.5 or so to recharge the battery. This coil is rated to generate up to about 2amps of charging current. This in mind, beware when running two bilge pumps.....a battery going bad (high internal resistance) and two bilge pumps running for a extending time is just enough to cook a lighting coil.

4. Ignition coil. Not many folks do not have a meter capable of resolving the almost dead short of the primary on this coil. But if you do, the resistance should be .078 to .106 DON'T forget to subtract the meter leads resistance by shorting together and subtracting, or adjusting the zero ohms pot, if you have it. Also, remove and insert the leads in the sockets to clean the connection.....I often see 1 ohm or more go down to .2 or .3 by performing this task.
NEXT, check the health of your spark plug wires, or high tension wires as the Brits like to say. The only way to test them properly is to remove the boots and get to the end of the wire. You can try jamming the point of the meter probes into the end, but due to the dirt and metal dust, it often does NOT give a solid connection / reading. If you have electrical contact cleaner, by all means spray with that first. You should read 3500 to 4700 ohms, or 3.5 to 4.7K ohms STEADY....while flexing the wires from end to end. If you get any fluctuations, they are bad...IE breaking up inside, turning to a high resistance powder of metal and rubber. I have seen bad plug wires cause problems with idle and low speed only, mid range only, and high speed only, and every combination thereof. Very strange !!!

If all these check out good, then I would swap the cdi with a known good unit....and known good means just what it says.....you have had it running in your boat, you removed it, and you put it away..The only other known good is a new unit. I have heard many a sad tale of days of trouble shooting with no luck, only to find out that the "known good" cdi your buddy gave or loaned you was not good after all.

Another interesting point is the "sparks when you let off the start button" syndrome. This always means on of two things......the cdi is bad, or the pulser coil is bad, or the wire from it to the e box is open.

Another good point to keep in mind: it is very possible to have two problems going on at once. One, like bad plug wires may have going on for a while, but no creating any major problems....the performance degrades so slowly you really don't notice it. Then, the charge coil insulation starts breaking down, or the connection from the winding to the terminal posts goes bad and starts arcing over. The two combined creat havoc, and can make diagnosis difficult.

After seeing so many stator coils have a good resistance, but test bad....I strongly advise against using resistance readings alone a gauge of health. Perform the cranking voltage output test!! Resistance readings are still useful for some work, so here they are for 61X and 62T:

61X: charge coil, brown / white trace to ground / black: 365 +- 10%

Pulser coil, white / red trace to ground / black: 12.6 to 15.4

62T: Charge coil, brown / white trace to ground / black: 497 to 608

Pulser coil, same as above

Lighting coil, green / green wires: 1.14 to 1.40 Since this coil is not grounded in any way to the stator frame, you can check this coil for leakage to ground (indicating bad insulation) by measuring between either green wire and ground with your meter set on the highest ohms scale, usually 20 to 40 meg ohms. If you get any reading, the coil is going bad.

There are other tests we perform to positively verify a coil's health, but the equipment is specialized and the proceedure is beyond the scope of this posting.

A note about the ignition coil: CDI ignition coils are much different than the coils in many cars, especially older cars. Those coils operate on the "collapsing magnetic field" principle to creat the high voltage. CDI ignition coils are in essence "step up transformers" simular to any any plug in wall transformer to operate various devices. The output is directly proportional to the input.

Another interesting proceedure you can do to gain more information about your coil's health.......hook your meter up to any coil, set it on the highest scale, and observe the reading. Leaving it there for an hour or more and come back and see what it reads. A lower reading or higher reading, or a reading that will not stabilize indicates a bad, or going bad coil. This may only work with better quality meters.

Some of this applies to Kawasaki too. If you want more info on Kawasaki, as well as Polaris, please contact me via e mail, NOT pm.

As most of you know, we can restore any stator and ignition coil to better than new condition. Please check our web site, or give us a call if you need more information.

cosander View Public Profile Send a private message to cosander Send email to cosander Find More Posts by cosander Add cosander to Your Contacts
I have the sparks when you let off the start button syndrom. Can you elaborate on how to tell what is causing this. It is a msd enhancer.

Chad

 

[Quinc]

"I have the sparks when you let off the start button syndrom. Can you elaborate on how to tell what is causing this. It is a msd enhancer."

Unhook your black and white stop wires and see if it sparks. check your ground wires to make sure they are clean and not corroded. If it still does it your msd enhancer is bad.