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Hyosung ignition failure

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Rider_clyde, Aug 9, 2014.

  1. Hey Guys, first post apologies for any newb things!

    So I'm trying to troubleshoot the ignition on my 2011 Hyosung GT650r EFI. Yes I know many of you don't like the brand, I'm OK with this, so any suggestions of "you shouldn't have bought it", "just ditch it", "Hyos are crap", any of that will just be straight up ignored as I do not want the thread to turn into another brand bashing exercise. I'm an engineering student, I like fixing things and that's just what I'll do, all machines are just that... machines. Unfortunately I lack the experience, detailed knowledge of all vehicle systems, and some tools to fix all things by myself, so that's where I'm hoping you guys can help me out :)

    Here's what I'm facing. The front cylinder does no longer fire. Through extensive testing and advise from several mechanics (swapping ignition coils, new spark plugs, swapping plug caps) I determined that the failed part was the front ignition coil. I've replaced the part twice in quick succession now. The first time I thought I'd received a faulty replacement coil as it burnt out again on the first ride, but the second time I began to think there is a little more going on here than I had thought. Clearly there is something that is forcing the the ignition coil to fail. I've explained this to a few friends that are mechanics and have received little in the way of what could be causing it on an EFI engine.

    When it failed:
    So on my maiden ride after replacing the coil for the second time I noticed the bike starting to miss as I got into the higher revs (>6000 rpm). As it was a long ride home I tried to pace myself as I feared getting stuck somewhere on the road. It started to get progressively worse as I rode, more and more misses, with some missing periods lasting a few seconds when I held throttle at a particular point. Once I got on the freeway I slowly accelerated up to speed. I got to the bottom of a big hill and as soon as I started climbing (which I'm associating with extra load on the engine) the front coil cut out completely and I was back to running on the single cylinder.

    Some things I've tried:
    Checked wiring harness to ECU and to battery.
    When ignition is set to ON, voltage at both coils is 11.22. A little under the 12 volt but I think that's ok when the bike is not running.

    The next thing I'm considering doing is replacing the ECU, but that's around $300 so I'd rather not replace any more parts until I've identified what exactly is wrong.

    Any thoughts or suggestions would be greatly appreciated!

  2. Often you will find members are more willing to help if they know who you are or at least a bit about you. We have a welcome lounge for such occasions should you wish to avail yourself of it.
  3. Oh ok, thanks for the suggestion.
  4. Have you measured voltage to the coils with engine running? 11.22v is low. Battery static voltage should be 12.6 to 12.8 with ignition off, and no less than 12.2 with ignition on. Battery is weak or you have a big voltage drop between battery & coils. When running, battery voltage should be between 13 - 14.5v. If battery voltage goes above 15v with engine running, coils & ECU can be damaged. Excessive voltage can be caused by faulty regulator / rectifier.

    You need a multimeter to test the failed coils to determine where they have failed. In the primary winding or secondary winding. Also need to test the plug caps. Perhaps an open circuited plug cap is causing secondary winding voltage to rise too high & burn out the secondary winding. Primary windings usually have 0-5 ohms, and secondary windings usually have 4000 - 12000 ohms. Plug caps usually have 4000 - 12000 ohms. Also check that engine is properly earthed to frame & battery.

    I'm guessing that it has a DC TCI. Which means 'battery powered Transistor Controlled Ignition'. Where battery current flows through primary winding of coil to the ECU, where it is switched on & off to earth by a transistor. With this type of ignition, there needs to be a few ohms resistance in the primary winding of the coils, otherwise there will be too much current flowing through the coil to the ECU, which may result in ECU being burned out. When you replaced the coil was it a genuine item or an aftermarket one? Did it have the correct resistance in the primary circuit? Perhaps Your ECU is damaged.
    • Like Like x 2
  5. Thanks for the information, I'll do some further measurements of voltages and resistances tomorrow and let you know. The coils I bought were genuine parts, but I can't guarantee it had the correct resistance in the primary coil as I didn't measure it.
    Another thing to note is that once I fitted the second coil after the first broke the bike still idled perfectly and didn't miss at all through the rev range whilst testing in neutral. I'm not sure what the implications of that could be however.
  6. Interesting. A couple of more things to check then. Hyosung side stand switches can wear & cause ignition problems, such as misfire, and could cause no spark to both coils but not to just one. You can bypass switch if you are not in the habit of leaving your stand down. Also the ECU may run a different map in neutral than it does in gear. Perhaps a dodgy neutral switch or wire could cause rapid map changing, inducing a misfire, but not total loss of spark.
  7. Alrighty, here comes some data. So the front coil is the one that stops working but the resistances came back as similar to the rear.
    Front Primary - 4.2 Ω
    Front Secondary - 11.80 kΩ
    Front plug cap - 9.61 kΩ
    Rear Primary - 4.5 Ω
    Rear Secondary - 11.80 kΩ
    Rear plug cap - 10.11 kΩ

    Here comes a shocker, I connected everything back to together to get the bike running to measure the running battery voltage and both cylinders were firing! A guy I was talking to today (also mechanic) mentioned he had difficulties once with an ignition coil causing misses only once it was warm and the heat had caused the coils to expand... maybe the same thing?
    Running battery voltage was 13.16 v, and then 12.25 v when I re-checked after I'd stopped the engine.
    The same friend as mentioned before suggested that a weak battery could be affecting the fuel pump and or something else could be slightly obstructing the line (suggested a new filter) and that this could be increasing the dwell time to a point were it burnt out... or something along those lines it was a little hard to follow.
    Side stand switch seems ok, the switch cuts both cylinders completely when triggered so I think it's unlikely to be that, I had a small issue with it once and it would just kill the engine, turned out just to need a clean and some anti rust.
  8. Battery voltage sounds Ok provided the running voltage was measured at idle. When reving the engine up to cruise revs you should be getting a battery float charge of 14 - 14.5 volts.

    Re heat and ingnition coils, yes they can break down when they get hot.The high voltage can flash to ground through micro cracks or winding insulation can flash over at higher temperatures.

    Fuel I am less convinced, it would affect both cylinders equally.
  9. Ok, I guess you next need to induce the fault, and test the coils again when it has no spark.
  10. Hey guys,

    Sorry I've been so long replying, what a crazy busy month!
    Update: I haven't gotten around to testing the coils one they're hot and seeing if I can induce the failure just yet, but hopefully I cant spare some time soon. another thing I'm considering doing is taking the ECU to a shop to get tested (a few of my mechanic friends suggested this was a good thing to try)
  11. Another thing to check. I have come across a few ignition coils where the high tension lead is not properly secured to the coil. It is just pushed into the coil and then the joint & lead is covered with heat shrink. Sometimes the High tension lead will pull out of the coil a bit, but you cant see it because it is covered with heat shrink. Try pulling or pushing the lead to see if it slips in & out of the heat shrink/coil. If so then try pushing the lead back into coil, and secure with zip ties clamped around the heat shrink.
    • Informative Informative x 1
  12. Missing problem under load? Worked when you bolted the bike back together? Before you spend any more money you need to eliminate fuel starvation. Hyosungs do have an issue with tank ventilation, I would check to see if your fuel tank is not breathing properly and creating a vacuum under heavy fuel load conditions.
  13. I don't know if you are still haveing the same problem, but here is a simple solution. My brother has a GV650 (2011 model), which is the same engine in a cruiser. Also this engine is the same as in oldeer Suzuki bikes. Hyosung built the engines for the SV650 Suzuki before they started building their own complete bikes. The GV650 had the same problem with the Ignition pack failing. They were replaced under warranty, failed again, then with authorisation from Hyosung, replaced under warranty with Suzuki ignition packs. That was early 2012. And since replacing the ignition packs with the Suziki parts, there hasn't been a problem with the bike since. Also I have heard this problem with a few other Hyosungs. When I last had my Kwaka serviced at Bike Biz in Parramatta, they had two Hyosungs in with the same problem.
  14. I would be looking for some thing that is connected to only the coil that is failing,ie: if it was a battery should it not kill both coils ( not the same one all the time ?) the same as fuel. just a place that I would be starting...............
  15. It wasn't my problem, I was just trying to help someone else, but thanks so much for the info, it has been duly noted, hopefully the chap with the issue will read your post.