hey guys!


the quads, bikes, boats, cars, have all had a great season until 2 weeks ago.
the KQ had a real weird mishap.


brother was riding and she up and quit......
I started looking and it and got code c24. ignition coil circuit fault.


found the ignition coil ground that goes back to the ECM to be melted about 6 inches back. totally fried like it got real hot!!


unwrapped wiring harness until it wasn't messed up anymore and soldered new wire and crimped new terminal on end to ground it at the coil.


I checked all the wiring and it all ohms out fine. and doesn't appear to be shorted to ground anywhere... still has the C24 code when cranking over.






what would cause that wire to get hot??


we have a new coil to bolt on this weekend but my question is: are we barking up the right tree here? the coil resistance tests were also fine, but I have power and ground to the coil but no spark...... gotta be the coil right?


we also plan to check all other grounds in the bike. Dad is a mechanic of 30 years and myself an apprentice electrician so we can figure this out we just hope the whole wiring harness or ecm aren't trashed.....


thanks for the help folks..


cheers

 

I had one do this, same fried wire, couldn't find anywhere else where the frame is earthed, so stuck in a thick earth wire from battery to frame. Code went out for me, and bike was working again once I had sorted the earth. Shortly afterwards the bike fried it's alternator plug, and the wires shorted onto the frame. Maybe this had something to do with the earth wire problem, maybe not.

 

new coil changed absolutely nothing for me.


coil is getting power and ground. the wiring ohms out clean as can be. all grounds are in good shape. I only measure 4.6 V on my power wire though........? is it that fussy on 5.0 V or more?


am I crazy to think I need a new ECM?? if I really need that 5.0 and my ECM is only sending 4.6....... right?


the only thing I can think of now is to really thoroughly check the pins of the ECM connector.... to ensure it is getting it's full 12 V through a good clean connection and outputting all 5V outputs properly....


this is a shame, this machine has been pretty good and a blast to ride...

 

I find electronic parts can read wildly different to what the book says they should, and still work fine. Never had an ECU go wrong on a 450 to 750 model. The 700 ECU takes more power than most when the bike is switched off, so those who don't use them much, found they had a flat battery, and Suzuki did produce a modified ECU which used less power.

Has the code gone out now you have fixed the earth to frame? On the one I did, the coil was not the reason the earth wire melted, never did work out why the wire melted, unless that faulty alternator plug (which I found about 2 weeks later) was feeding high current into the frame and the feeble earth wire couldn't cope. Are you getting a spark at the spark plug?

 

I had not tried yet to add a new frame ground.... I figured that it used to run and I shouldn't have to modify my wiring, will try this weekend or tomorrow night with booster cables or a chunk of wire from work. and I forgot about that idea as I was up at the cottage without internet connection.


your replies on this thread are the only place online I can find someone saying they had a KQ do this. I will be checking my alternator plug as well before I fry mine.


everything else works fine so I can't imagine a bad ECU, then again, feeding high current into the frame could cause one...

 

sorry have been busy and not had much of a chance to play with this bike.


-adding a ground did nothing for me.
-alternator/ stator plug is fine as is every other connection in the machine. would swear the machine never saw dirt and moisture in its life just by looking at the connections. now they are dielectric greased.
- crank sensor tests fine
- stator ohms fine but not able to test voltage as the spec in my book if for 5000 rpm and the engine doesn't run
- regulator/rectifier diode tests are fine.
- 5 volts at the coil when key is on but doesn't go up when cranking, which I assume means the ECM is not trying to fire it.
- every single other function of this machine works perfectly.


what else could possibly have caused this wire to melt?? there was obviously quite some current on it as the way it looked can be compared to residential wiring after a minor fire or the wiring in a really old light fixture from the heat of the bulbs.....
-

 

You still haven't said if you have a spark, though it should fault code if "the coil has not fired after 11 revolutions." On the one I had the earth wire had melted almost all the way back to the battery, are you sure it didn't melt another wire in the loom and short or burn it out?

 

I found another bad spot in the wire but it hasn't appeared to have gotten hot enough to melt any other wires to earth anywhere. will be surely double checking this as I am about stumped but not sure enough of myself to buy an ECM.


my bad, no spark whatsoever. the ECM is not firing the coil.

 

so I took my ecm to the local dealer and they happened to have a compatible bike in the shop. they plugged her in and that bike acted the same. this ecm is TOAST!!


now I just have to try and find one used and quadruple check all the wiring before I plug her in......


thanks for the help

 

thought i'd finally post back.


ended up replacing the ECM and wiring harness. the Ecm plug was faulty and caused the ecm to die. the new ecm fired the bike right up but it didn't run right. it now runs fine with the exception of idling a little rough on startup, but I think that's a separate issue. starts right up and has all the ***** she ever did. can't wait for spring, will just enjoy my 86 Phazer for now


thanks again for the advice. happy riding