Forums 🚥 PiT STOP 🔧 Hyosung Technical Help 08 gt250 8k idle Reply To: 08 gt250 8k idle
Have you got any Fi light warnings ? (2008 model, so I assume it is the SENTEC EFi model) (also 2009 is the last year we saw carb models changing to EFi)
If possible, did you follow service manual to get error code from the ECU ?
If this was a carb bike = high revs usually means extra air is coming inside the bike (intake system leak)
As its an EFi model = I understand that ISCV was changed , could there be any chance it is failing again ? Have you tried your old ISCV unit if you did not throw it away by now.
Otherwise, using the service manual (which has the readings) get a meter and test these parts:
- MAP sensor (it will be on the throttle body or airbox as you have an early model EFi likely (that’s if the previous owners didn’t upgrade it to newer injection parts)
- Lambda Sensor ? (Oyxgen sensor in the exhaust) => Suppose the ECU thinks the mixture is off (wrong signals by the oxgen sensor) => injection system raises more revs.
- Engine Temp Sensor at the front cylinder ==> If it thinks its still cold , the ECU revs up to warm it up? Test that sensor.
- AIT sensor = Air intake temperature sensor (sometimes its called pressure sensor as weird as that sounds) it will be sitting on the airbox (if Hyosung put it there)
- EGR unit = It’s a big electronic box that has 2 pipes => going to front and rear engine ==> block the air feed or disconnect it and see if it changes anything (since the lambda sensor will be in the exhaust pipe)
This is my guess as annoyingly Sentec & Daewoo ECU’s can be troublesome to diagnose.
If Simon on this forum doesn’t say it , I will say that strip the harness out of the bike & clean every connector you can find. You’ll be surprised how much a little resistance in the wires can skew readings to the ECU.
Keep us updated!
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