Dies on idle (after 1-3 minutes)
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Bike Model = : GV250 2012
Hi,
My GV250 has been out of commision for a few months now, I needed a new fuel pump and TPS, the fuel pump I knew I needed because if I kept priming the bike over and over I got it to run fine, if I didnt do this before the bike would lean out and die. I needed a new TPS because the bike would backfire from the exhaust and the intake before and it was idling at 2k rpms. I just replaced the TPS today, I calibrated it to .8V closed throttle, now the bike will hover 1.3k-1.5k rpms no backfiring or missfires. But now it will idle for a few minutes at most and start to go down further and further until it reaches 1k rpms and dies. Is the TPS of the 2012 supposed to be at .8V? maybe I have it set too low? On a cold start itll go to 3k for a little come down and stay no problems for awhile around 1.5k before it just starts coming down further and dying. Right now im thinking its injectors or ISC? I did replace the ISC a few months ago though so thats why im stumped, and it was functioning perfect after I replaced it. If someone could tell me if .8V closed throttle is correct and if it is, where should I check next?
Thanks any help is appreciated.
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another thing tommorow I am going to check if the ISC is getting 12v and ground if not ill try jumping whatever it is missing, also if 12v and ground is there I have my original ISC I unclogged I will test that after as well. If anyone has any other suggestions let me know please thanks.
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Check your coils for resistance and see if your HT Caps are arc-ing (loose sparks out of the plug)
This says its for 125GT but ignore the title, you want to use it as a guide to check resistance of your coils and the stator unit too.
Rectifier – How to Test Stator , Battery , Regulator – GT125R Carby
I once had to replace everything on a 2012 DAEWOO model GV250 and the customer was also stumped, it turned out, despite the stator working, it was the root cause.
How? The resistance was OK for the pulse sensor and stator was charging 70v strong around 4k revs , but as engine got hotter and hotter, it started to die down.
We replaced the stator unit , and it was fine since thenAlso the Daewoo ECU is my most frustrating ECU to work on compared to Delphi or Sentec ones , they absolutely want every single connector on the plug to be free of rust , oxidization, dirt etc. Contact Cleaner is advised.
Do not put liquids on the ECU itself = Use compressed air only. Just the ECU area you have to be extra caution, it only takes 1 wire or 1 pin to ruin the whole thing for good and it is near impossible to get a new Daewoo ECU.
I would deal with the TPS later, as its already idling at 1.5k rpm, although just a minor tweak should make her idle at 1800 rpm (Brand new GV’s idle at 1800rpm straight from the factory, it was the carb models that idle’d lower around 1.5K rpm as mandated by the Hyosung service manual)
Also it helps to get fresh plugs again (CR8E Yellow or LASER Rainbow plugs only) – They don’t like “IX Iridium” plugs.
Also if it has stock plug caps, throw them away, they always let us down , and get yourself NGK caps. Very recommended.
If not , use SV650 1999 caps (ensure your engine hole can still be covered to stop dirt or water going to your plugs!) and use SV650 1999 coils (they are bigger) but made by Mitsubish Japan (get OEM ones) , they may be big, so expect to make room inside your plastic cover under the tank for them.
However, if your HANKUK Korea coils are OK, leave them there and just focus on the HT caps. Generally when the plugs and caps go bad , it takes out the coil with it!
Check this out too:
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Thank you marcel I appreciate the comments, I will replace everything mentioned, going to start with caps and plugs. The coils themselves aren’t OEM I bought universal coils from a local motorcycle shop and they have been working for me for a few months before I ran into this issue. I know you stated you literally replaced everything, and still the bike wasn’t running and that it was the stator. When you did replace everything what were the symptoms you were running into? Was it similar to my situation where the bike starts cold no issues comes down to normal idle for a few minutes and then gradually dies?
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Cold starts where not an issue, and sometimes when its hot, it dies, then i have to continuously crank to get it going which damaged the starter motor in the end , so replaced the starter motor too and its relay.
You could check the service manual for the EFi models to check resistance levels needed for the coils and make sure your coils match (I can’t confirm what the SV650 ones are as i forgot!)
However Hyosung GV650 carby , GT650 carby & GT250 (some efi early models) did use the Mitsubishi Japan SV650 coils (It will have the Mitsubishi logo imprinted on it)
Some GV25o EFi models used GV650 smaller coils – So Hyosung has been known to interchange coils across all their models as long the specific ECU accepts it.
Speaking of temperature, test your ET sensor , here is a similar topic about it:
If the bike had brand new parts (or used parts from a verified working donor) – you should not have problems. This means now, you will spend some time with your multi-meter to test every single sensor on the bike and verify that it is still spec according to the manual.
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Ok will do, ill test the ET (IAT im assuming you are referring to on the GV250), I need to check if its getting 5v cause I tested all the sensors but couldn’t read 5v from the IAT sensor. Ill have to test while cranking as well cause that might be the culprit, but honestly my fuel lines while dont have any kinks or cracks they still are old and a little spotty, some spots have like rubber particles around them. For the majority it doesn’t look bad but could be that, but i’m also heavily leaning towards injectors right now too. Ill have to figure out a way to test fuel pressure, because I know there is no Schrader valve, Hyosung’s while nice bikes they sure suck when you have to work on them 😕 especially the early efi models… thanks for the replies marcel hopefully its something simple but honestly my harness has seen better days so really at my wits end with it. Wish me luck, lord knows I need it.
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No IAT on the GV250 is on the airbox and ET on the physical front engine cylinder.
IAT = Ohms text.
ET= Ohms test.Don’t put IAT in water.
If there is continued issues with the ECU, there is a new upgrade system below: (I sell the fuel pump separate if needed) , i “may” still have older sensors like ET etc… I can always dig them out and see and included them in the bundle.
I have fuel pipes for the GV , eBay does not allow me to export them. So best to do the deal via email instead , or otherwise look for Delphi systems at your local wreckers , now you bike has a 2018 overhaul and yes I also sell the 2018 stator & regulator as they are entirely different now.
Harness & ECU = https://www.ebay.co.uk/itm/257182139648
2018 plugs for injectors & ET sensor etc = https://www.ebay.co.uk/itm/257148903272
Fuel pump wire = https://www.ebay.co.uk/itm/256602588520
Fuel Pump (Delphi ECU uses Blue Pump and has different pessure rating) https://www.ebay.co.uk/itm/257147094683
Main fuel hose = https://www.ebay.co.uk/itm/257155594594
Injectors = Hoses are OK , but i would get braided ones (can be supplied if needed) https://www.ebay.co.uk/itm/257150820566
IAT Sensor (untested) = https://www.ebay.co.uk/itm/257147129279
ET Sensor (untested but i am suspicious it works) = https://www.ebay.co.uk/itm/257134793489 (for future spare!)
TPS = https://www.ebay.co.uk/itm/257150787245
MAF = https://www.ebay.co.uk/itm/257150806030
IAC = https://www.ebay.co.uk/itm/257152400938
Stator/Reg combo = Needed for 2018 harness! = https://www.ebay.co.uk/itm/257148968953
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Thanks for the links Marcel, I actually just fixed the bike a couple hours ago. The sparks were completely fouled and the tips on both were white, this is from when the fuel pump was dying, and eventually it fully went and the bike was stuttering before the pump died. Also I put like 8000 miles on them too, one thing I seem to still have though is a hunting idle, the ISC and TPS and fuel pump are new so are the coils and the sparks. Only thing left I can think of is the caps themselves or maybe something to do with charging? Though I will say the bike does charge and stay at a constant 13.4v idle and it gets up to 14v under load. Maybe some new caps and rectifier will make it run better than factory though and the hunting will subside 🙄 Thanks for your help Marcel!
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Go for a small ride and come back, let it cool down quickly , report back on how it ran on the road ? And then remove your plugs , check again.
NGK is a safe call for caps. And test the resistance of coils and report back the figures.
Check the manual and test your Lambda Sensor (O2 sensor) in the exhaust pipe too. These report back burnt (or unburnt) mixture back to the ECU. Sometimes they just crap out needing a replacement.
Although, the only way to be sure about any part is to use the manual and actually write down the figures reported , then you know if a cerrtain part needs replacing. It could take 1 random sensor or part to throw whole bike out of balance.
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Check your coils for resistance and see if your HT Caps are arc-ing (loose sparks out of the plug) This says its for 125GT but ignore the title, you want to use it as a guide to check resistance of your coils and the stator unit too.
Rectifier – How to Test Stator , Battery , Regulator – GT125R Carby
https://hyoriders.club/forums/topic/rectifier/embed/#?secret=XRZVPeFVeD#?secret=NKSVOrwuC3 I once had to replace everything on a 2012 DAEWOO model GV250 and the customer was also stumped, it turned out, despite the stator working, it was the root cause. How? The resistance was OK for the pulse sensor and stator was charging 70v strong around 4k revs , but as engine got hotter and hotter, it started to die down. We replaced the stator unit , and it was fine since then Also the Daewoo ECU is my most frustrating ECU to work on compared to Delphi or Sentec ones , they absolutely want every single connector on the plug to be free of rust , oxidization, dirt etc. Contact Cleaner is advised. Do not put liquids on the ECU itself = Use compressed air only. Just the ECU area you have to be extra caution, it only takes 1 wire or 1 pin to ruin the whole thing for good and it is near impossible to get a new Daewoo ECU. I would deal with the TPS later, as its already idling at 1.5k rpm, although just a minor tweak should make her idle at 1800 rpm (Brand new GV’s idle at 1800rpm straight from the factory, it was the carb models that idle’d lower around 1.5K rpm as mandated by the Hyosung service manual) Also it helps to get fresh plugs again (CR8E Yellow or LASER Rainbow plugs only) – They don’t like “IX Iridium” plugs. Also if it has stock plug caps, throw them away, they always let us down , and get yourself NGK caps. Very recommended. If not , use SV650 1999 caps (ensure your engine hole can still be covered to stop dirt or water going to your plugs!) and use SV650 1999 coils (they are bigger) but made by Mitsubish Japan (get OEM ones) , they may be big, so expect to make room inside your plastic cover under the tank for them. However, if your HANKUK Korea coils are OK, leave them there and just focus on the HT caps. Generally when the plugs and caps go bad , it takes out the coil with it! Check this out too:
Hey good morning!
What NGK caps were you referring to? Do you have a link to these?
That would greatly help me out, tysm!
'12 GV250 EFI
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Check your coils for resistance and see if your HT Caps are arc-ing (loose sparks out of the plug) This says its for 125GT but ignore the title, you want to use it as a guide to check resistance of your coils and the stator unit too.
Rectifier – How to Test Stator , Battery , Regulator – GT125R Carby
https://hyoriders.club/forums/topic/rectifier/embed/#?secret=XRZVPeFVeD#?secret=NKSVOrwuC3 I once had to replace everything on a 2012 DAEWOO model GV250 and the customer was also stumped, it turned out, despite the stator working, it was the root cause. How? The resistance was OK for the pulse sensor and stator was charging 70v strong around 4k revs , but as engine got hotter and hotter, it started to die down. We replaced the stator unit , and it was fine since then Also the Daewoo ECU is my most frustrating ECU to work on compared to Delphi or Sentec ones , they absolutely want every single connector on the plug to be free of rust , oxidization, dirt etc. Contact Cleaner is advised. Do not put liquids on the ECU itself = Use compressed air only. Just the ECU area you have to be extra caution, it only takes 1 wire or 1 pin to ruin the whole thing for good and it is near impossible to get a new Daewoo ECU. I would deal with the TPS later, as its already idling at 1.5k rpm, although just a minor tweak should make her idle at 1800 rpm (Brand new GV’s idle at 1800rpm straight from the factory, it was the carb models that idle’d lower around 1.5K rpm as mandated by the Hyosung service manual) Also it helps to get fresh plugs again (CR8E Yellow or LASER Rainbow plugs only) – They don’t like “IX Iridium” plugs. Also if it has stock plug caps, throw them away, they always let us down , and get yourself NGK caps. Very recommended. If not , use SV650 1999 caps (ensure your engine hole can still be covered to stop dirt or water going to your plugs!) and use SV650 1999 coils (they are bigger) but made by Mitsubish Japan (get OEM ones) , they may be big, so expect to make room inside your plastic cover under the tank for them. However, if your HANKUK Korea coils are OK, leave them there and just focus on the HT caps. Generally when the plugs and caps go bad , it takes out the coil with it! Check this out too:
Hey good morning! What NGK caps were you referring to? Do you have a link to these? That would greatly help me out, tysm!
They are on this store, so you can see what they look like, and you also tend to find them on most bike garages locally if it is urgent, just screenshot the ones you see as they fit the Hyosung GV
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