GT250R won't start (but cranks)

**Sentox** · 23rd June 2010, 17:37

Originally Posted by DangerousBastard

Yeah bro my guess is water in the fuel tank - only will need a teaspoonfull to make it quit. Try keeping it full to the eyeballs - stops condensation forming.

So that's why the manual says to fill the tank right up when putting it into storage.

That must be 400kms on that bike!

Yeah, I make about 400kms on a tank. Quite nice to ride Hastings > Palmerston and back on $20

**CookMySock** · 23rd June 2010, 22:30

Yeah what happens is, day-to-night the air temperature changes heaps, so in the daytime the air in the tank warms up and expands, pushing some small amount of air out. Over night, the air in the tank cools and contracts, sucking in fresh moisture-laden air, which then condenses the moisture out it, onto the inside of the cold tank which runs down into the fuel and settles in a puddle underneath the fuel (water is heavier than fuel). The cycle repeats every night, and the tank slowly gathers water. If the tank is near-full, it can't do it - not anywhere near so much anyway.

Steve

**SS90** · 24th June 2010, 03:46

I'm impressed with someone going out to help like that, pretty rare these days.

I don't have a crystal ball, but I suspect the fault is not water in the tank.

Working backwards, I read that the bike (when hill started) would run on full throttle, but only about idle speed.

On a bike with a sealed airbox, that is a good sign that the airbox is flooded.

Because the guy has cranked it over and over, but it would not start (and it is injected), I would suspect that there is a fault with either the air temperature sensor, or the ECU.

Injected vehicles do not have a choke (some early injected stuff had a "fast idle" lever that simply held the butterfly open a few degrees, while the engine warmed up, but this did not actually enrichen the mixture at all.

With fuel injection, the ECU is fed any variable data it may need for correct operation (air temperature is one), and the ECU will know that 1) this is a cold start situation (because the water temp is low) and 2) the air temp is cold as well, therefore, the ECU knows it will need to enrichen the air/fuel mixture, so the engine starts.

Normally, if any of the sensors are faulty, the dash will show a fault code, but, sometimes, with a cheaper system, it will not.

I would advise that if you have a problem again like this (not starting when cold), you should contact the dealer...... 1000 KM over the warranty? They would have to be mean as hell not to sort it, as well as pick it up for you.

While history is littered with unreasonable customers, with unrealistic demands/expectations, you, on the surface seem to be a reasonable Hyosung customer who needs help.

I am sure they will look after you!

**TimeOut** · 24th June 2010, 07:10

I'd go with one of the temperature sensors as well, they can fail intermittently.

My sons 6r did the same only once but the computer couldn't find the fault

**Sentox** · 24th June 2010, 08:07

Originally Posted by SS90

I'm impressed with someone going out to help like that, pretty rare these days.

Me too: MSTRS is a fantastic guy. And if anyone is looking for mentoring, I can't recommend him enough.

Working backwards, I read that the bike (when hill started) would run on full throttle, but only about idle speed.

Not quite, I should explain slightly better (or try to, anyway). I'm at the top of quite a long hill, so I had time for several attempts. First time, once I got the engine turning over, I pulled the clutch back in, but it wouldn't run on its own. So I did it again, and just let the hill keep turning it, while holding the throttle open. Took about 15 meters or so before the engine started actually responding to the throttle and accelerating.

Because the guy has cranked it over and over, but it would not start (and it is injected), I would suspect that there is a fault with either the air temperature sensor, or the ECU.

Would either of these explain an intermittent fault where occasionally when the clutch is pulled in (mostly when coming to a stop) the engine cuts out cleanly (as if you turned the key or hit the killswitch)? It hasn't happened for some time now, and the mechanics could never track it down at servicing, but it's always bugged me.

**SS90** · 24th June 2010, 08:37

Originally Posted by Sentox

Would either of these explain an intermittent fault where occasionally when the clutch is pulled in (mostly when coming to a stop) the engine cuts out cleanly (as if you turned the key or hit the killswitch)? It hasn't happened for some time now, and the mechanics could never track it down at servicing, but it's always bugged me.

Erm, unfortunately no.

The EFI "fast idle" programmes have always been a contentious point for owners (the really modern stuff is fine, but stuff even 5 or 6 years ago was always a compromise, where they tries to use "one setting for all" markets, meaning that they would have the "fast idle" speed really quite high (something like 1500 RPM), and this would operate until way after it was at N.O.T (normal operating temperature)
, meaning that the bikes would only ever really have a nice low idle after it was at it's normal operating temp, and if you just pootled around to work and back, it never really got to the correct temperature, therefore the "fast idle" circuit never switched off.

Many customers used to complain of this a few years ago "my choke doesn't switch off" (etc), when in reality, it was not actually a problem.

It would seem the opposite is true of your bike, where by (perhaps), since your bike is a mass produced machine, and produced for the world market, and NZ has quite a cold climate, there is a chance that Hyosung have chosen a temperature quite low to switch off the fast idle circuit, and simply, in some situations, the idle is too low on your bike (maybe it is only when you are doing some commuting, and the bike is quite cold?

You would need to discuss it with your mechanic, but I would test this theory by simply reducing the area of your radiator (duct tape is the trick, perhaps by 1/8th to start with), and see if this raises the temp of your bike (during winter), not so much that it runs hotter, but more so that it warms up faster, and it may help with the stalling (the fast idle will stay on longer)

While a VT250 is carbed, 10 years ago, I taped up a portion of my girlfriends VT250 radiator (because it never got anything like warm on the 5k ride to work), and it heated up nicely for the journey all year round.

I simply removed the tape when she went on a long journey.

of course, this is nothing to do with the cold starting circuit, that is different (with EFI, don't get confused with "fast idle" and "cold start", while the two are the same process on a carbed bike, EFI they only really share two common sensory (air temperature, and water temperature), it would be safe to assume that the sensor that measures and displays your water temp is the same unit that supplies the data to the control unit, and if the temp displays correctly, then it may well be that the air temp sensor is faulty (although it is fair to assume that there would be a trouble code for that!)

Hope this helps!

**MSTRS:Me** · 24th June 2010, 08:48

Sentox's bike is aircooled. It has a smallish oilcooler.
I'm still of 2 minds as to what the problem was (is?), but the fact that the engine had all 3 of the required components to run, yet wouldn't even hint at firing...leaves me thinking sufficient fuel was being denied. IE some sort of blockage in the injectors. There was some getting through because the plugs had a strong petrol smell, but were not wet with the stuff.

**CookMySock** · 24th June 2010, 08:56

I bet there are plenty of modern vehicles on the road with a faulty temperature transducer. Engine doesn't warm up well, uses a bit more fuel than the others, pipe runs a bit black, smells a bit of unburned fuel, etc.

Fortunately, temp sensors are perfectly trivial to test if you can get a cal sheet for them - it's just the time involved for the EFI technician of pulling them off and running a cal test on them. It's probably cheaper to just replace them, but now the price starts to get up.

The service manual for the 2010 EFI bike is freely available, so I would be tempted to read up further and form an educated opinion. EFI isn't difficult - it's just resistive sensors talking to the ECU, so don't be afraid of it.

Steve

**SS90** · 24th June 2010, 09:03

Originally Posted by MSTRS

Sentox's bike is aircooled. It has a smallish oilcooler.
I'm still of 2 minds as to what the problem was (is?), but the fact that the engine had all 3 of the required components to run, yet wouldn't even hint at firing...leaves me thinking sufficient fuel was being denied. IE some sort of blockage in the injectors. There was some getting through because the plugs had a strong petrol smell, but were not wet with the stuff.

Oh, I don't realise that the EFI Hyosung's where still air cooled!

I SHOULD NEVER ASSUME!

Wow, that is really a surprise.

In that case, while I Realise that everyone is suspecting fuel problems, I still have a feeling that there sensor required for measuring the temperature of the engine is suspect.

My only experience with air cooled EFI bikes that have an automatic fast idle circuit, is the first 2 series of Harley Davidson (EFI).

They had an engine temperature sensor located on the rear cylinder head, and I remember 2 being faulty and needed replacing.

My experience with EFI stuff is if there is water in the fuel, (EFI have water traps in the filters remember) the problem will not suddenly appear (fine one day, not starting the next), but rather surging, rough running, loosing power etc, for weeks before something stops working altogether.

The fact that he seems to have stalling occasionally, and then one day (suddenly) it won't start from cold.

If I was servicing the bike, I would suspect the temp sensor (normally located on the cylinder head), which can easily be tested with an OHM meter, and compared against the specs in the book, which normally requires a cold test, and a "normal operating temp" test....... 2 different resistances, 1) cold start 2)fast idle off

**MSTRS:Me** · 24th June 2010, 09:17

I'm floundering here, just a little, so bear with me...
'Modern' EFI utilises a choke function by opening the injectors a little more to provide a richer mix? Not the fast idle that was used previously?
The EFI opens the injectors, based on cam timing and throttle position. Right? So when an injector is not 'open', it is sealed completely? Nothing can pass through it?
So, if bad fuel is not the cause, then there is a fault between the EFI and injectors. Yet some fuel was getting through (smelly plugs).
I had a faulty TPS on the gixxer, but the bike still idled. It just didn't respond to the throttle being twisted. Doesn't seem to be the case here.

**bogan** · 24th June 2010, 09:24

time for my 2c

I've had the slow to run properly hill start thing many a time, usually after trying to start it other ways and flooding the engine, just takes a little bit for the mix to even out, so I wouldn't worry bout that part of it; starting cowboyz's TT took bout 50m to get it responding to throttle

could be a faulty temperature sensor as SS90 said, may be a bastard to track down as sound like an intermittent rather than permanent fault though. Fuel problem don't explain the occasional cutting out , so I'd still give the temperature sensors a once over.

I got multimeters and shit if you want some help checking out any of the electricals.

**bogan** · 24th June 2010, 09:29

Originally Posted by MSTRS

I'm floundering here, just a little, so bear with me...
'Modern' EFI utilises a choke function by opening the injectors a little more to provide a richer mix? Not the fast idle that was used previously?
The EFI opens the injectors, based on cam timing and throttle position. Right? So when an injector is not 'open', it is sealed completely? Nothing can pass through it?
So, if bad fuel is not the cause, then there is a fault between the EFI and injectors. Yet some fuel was getting through (smelly plugs).
I had a faulty TPS on the gixxer, but the bike still idled. It just didn't respond to the throttle being twisted. Doesn't seem to be the case here.

EFI opens injectors based on the amount of air flowing into the engine, more throttle=more air, colder temp=more air. It opens (yeh, always open or closed) the injectors when the engine is at right angle but this doesn't change the amount of fuel injected at all. Some engines have exhaust sensors which provide feedback on the mix, but I doubt this is the case on a 250?

edit, some car EFI still use the fast idle technique, donor engine for my van is sposed to, but the actuator wouldn't fit, it still runs fine without it.

**SS90** · 24th June 2010, 09:39

Originally Posted by MSTRS

I'm floundering here, just a little, so bear with me...
'Modern' EFI utilises a choke function by opening the injectors a little more to provide a richer mix? Not the fast idle that was used previously?
The EFI opens the injectors, based on cam timing and throttle position. Right? So when an injector is not 'open', it is sealed completely? Nothing can pass through it?
So, if bad fuel is not the cause, then there is a fault between the EFI and injectors. Yet some fuel was getting through (smelly plugs).
I had a faulty TPS on the gixxer, but the bike still idled. It just didn't respond to the throttle being twisted. Doesn't seem to be the case here.

The important thing is that the old EFI "fast idle" lever (that was simply the enrichiner lever you would normally see on a carbed bike), was connected to the throttle cable, and simply pulled the throttle cable up a few degrees (the same as holding the throttle open with your hand.

This in no way assisted starting..... the enrichening of the mixture was controlled by the ECU.

the only reason you needed a fast idle lever was because the engine was cold, and even with a rich mixture (via the ECU), the standard idle speed was too low for a cold engine.

Modern stuff has done away with this basic stuff.

**MSTRS:Me** · 24th June 2010, 09:42

OK. So injectors don't have degrees of open? Obviously they were opening in this case. So if the plugs were smelly, but not wet, what would this mean?