GT250R won't start (but cranks)

[Sentox]

First of all, apologies to the mods if this is in the wrong place. Not really sure what category it belongs under at present, and I was hoping more people might see it here.

Anyway, the basics: last rode the bike (Hyosung GT250R, EFI) on Saturday. No problems; everything running fine. Go to jump on it today, and it cranks but won't start. Headlights seem nice and bright, starter motor sounds normal and keeps turning over, so I'm thinking the battery is ok. It does the usual startup process: fuel pump primes - at least I think that's the loud whirring noise, I may be mistaken on this one - and the tach needle cycles from max to zero; no warning lights or anything out of the ordinary.

I've been trying to crank it every so often, and a couple of times it has caught after 5 or 6 seconds of turning over, but idles extremely lumpy (under 1k rpm) for a few seconds then dies again. On my last attempt to start it it wouldn't catch at all, and the tech needle was going a little crazy, which was strange.

I'm hoping someone might have some idea of what might be at fault. I've thought about checking the spark on someone's advice, but it looks very difficult to get at the plugs without dismantling a lot of stuff (if anyone who knows Hyosungs has any advice in this it would be helpful as well).

Thanks guys!

[MSTRS]

Your description of symptoms makes me think that the auto choke is not actuating properly. Or you've somehow flooded the engine...is that possible with injection?

[Sentox]

One thing I didn't think of is that it has been outdoors (albeit with a bike cover) overnight. Usually it stays in the garage. Could condensation or such cause issues?

[CookMySock]

The tach needle jumping around normally means theres a fault with the ignition pickup or associated wiring. Unplug the pickup and CDI and see if theres any moisture in the connectors.

Steve

[MSTRS]

One thing I didn't think of is that it has been outdoors (albeit with a bike cover) overnight. Usually it stays in the garage. Could condensation or such cause issues?
If that's the one thing different from normal (and you don't normally have a problem starting) then there may be something in what you say re condensation. It was pretty wet yesterday...

[MSTRS]

Any luck sorting it?

[Sentox]

Any luck sorting it?

Got caught up with some work at home, unfortunately, and soon I have to go and meet someone. I'm hoping I can get home early enough this evening to get stuck into it, otherwise I'll be getting up early in the morning to have a crack at it. I'm trying to wait until I have a few hours spare before I start unscrewing stuff.

[MSTRS]

Whatever it is, it will be something very simple. Diagnosing the fault is the hard part...because so many causes can have the same symptoms.

[wanpo]

Tried push starting?
I've had problems getting mine (albeit carbureted) started on some mornings, I just keep away at it, giving it throttle when it catches, hoping I don't flood the engine, until it doesn't stall and revs up.

[imdying]

Tighten your battery leads.

[Swoop]

Check the label on the frame.
If it says "Hyosung" you will need to replace the bike with something more reliable.

[Sentox]

Checked battery leads, electrical connections, and spark this morning. Couldn't find anything loose or any moisture, and spark seemed nice and strong, so it's probably going to the workshop at this rate. Mechanic recommended I let it sit for a few days and go over the connections with CRC, so I'll do that and charge the battery, but otherwise things are going beyond my limited knowledge (and toolset). Unfortunately I don't have a way of moving the bike for the next fortnight or so. In my experience, it takes about three days for riding withdrawals to set in :laugh:

[MSTRS]

Still refusing to start?

[Sentox]

See above ^ I think we posted at virtually the same time :p But yeah, it looks like I'm going to be offroad for a little while.

[CookMySock]

It's under warranty isn't it? I'd be calling them up and telling them to get around there and sort it pronto.

Steve

[MSTRS]

Damn. Huey has turned it on as well.

[Sentox]

It's under warranty isn't it? I'd be calling them up and telling them to get around there and sort it pronto.

According to my warranty booklet, I have 12 months or 10,000km... whichever comes first. I'm at 11,000km now :bash:

[CookMySock]

Hrm I'd call them up and try it on.

Steve

[slofox]

According to my warranty booklet, I have 12 months or 10,000km... whichever comes first. I'm at 11,000km now :bash:

That's a pretty limited warranty n'est ce pas? My last new bike had two years and unlimited km's...

[MSTRS]

Have you tried some ether? ie Start Ya Bastard.

[Sentox]

I've read that ether combustion is too violent for small capacity engines...

My old beatup car failed its warrant this morning, so life is just getting peachier by the minute :laugh: At this point I think I would just take it to the dealer and go from there, but I'm not overly fussed on pushing it 30km. Should be able to sort something out in a week or two though.

[MSTRS]

Just talked to a mechanic. He agrees - no ether. He also agrees that the problem is fuel-related. He suggests that the plug/s are fouled, so replace with new ones and try again.

[Sentox]

Just talked to a mechanic. He agrees - no ether. He also agrees that the problem is fuel-related. He suggests that the plug/s are fouled, so replace with new ones and try again.

Hmmm... the spark plugs seemed in alright condition. Light brown, no appreciable build-up. I suppose they could still be bad, but it seems strange the bike would go from running perfectly to refusing to start. Still, not the most expensive thing to try, although getting at the front plug looks to be all kinds of fun.

[MSTRS]

Hmmm... the spark plugs seemed in alright condition. Light brown, no appreciable build-up. I suppose they could still be bad, but it seems strange the bike would go from running perfectly to refusing to start. Still, not the most expensive thing to try, although getting at the front plug looks to be all kinds of fun.

If (and that is a big 'if') the plugs are fouled, it happened on starting.

[CookMySock]

All of that plug fouling is fairly unlikely on a modern fuel-injected bike. I'd say something simple has spat the dummy.

Any fuel smell from the exhaust after trying to start?

Water down the plug holes? (theres supposed to be drains)

A big gulp of water in the fuel? (can you bleed the EFI?)


Steve

[MSTRS]

Update that isn't...
Since Sentox doesn't live toooo far away from me, I took a jaunt out there yesterday arvo.
I took some new iridium plugs and an open mind...
Old plugs possibly a bit worn (strange being only 11000kms old), but their colour was good, and gap about right, but they did smell strongly of petrol. So gave the engine a spin with them out to air the cylinders. Checked for compression puffs (ok). Put the new plugs on the leads and span again to check spark (ok). Installed them and tried again. No go. Checked the operation of the sidestand killswitch - seemed ok and there was spark happening anyway. Checked the exhaust outlet for blocked muffler. No problem with flow there. Turning over the engine doesn't seem to be taxing the battery, but used jumper cables too.
So. We have a fuel pump that whirrs and because it stops, seems to pressurise the system ok. We have fuel entering the cylinders. We have compression. We have spark. What we don't have is a going engine.
I have suggested he try crash starting down the hill he lives on, but wasn't volunteering for the push back up if still no go.
That is about the extent of direct assistance that I can provide on site.
Anyone else got some info that might help?

[CookMySock]

Pull the fuel lines off the injectors, start the fuel pump, and flush into a jar. Check for flow. Check for water.

Replace EFI fuel filter.

Temporarily close plug gaps wayyyy up (checks for weak ignition.)

Unbolt oil cooler (pull aside - do not un-pipe) pull front valve cover off - check for rotating camshaft. :shit:

Pre-heat plugs with gas flame, immediately refit and start.

um um um um... :scratch:

Steve

[Sentox]

It runs again. I've been avoiding the hill start option thus far because I'm on quite a steep hill, and had no backup in case I got stranded at the bottom. Managed to get assistance today. Once I got it rolling the engine turned over and ran, but for about 15-20 meters there was no throttle response at all. At that point I suddenly got a surge of power ("felt" like a blockage suddenly cleared, if that makes sense) and away it went. Gave it a short ride to get it up to temp, came back, and key started it a few times. All is well so far.

Thanks again to everyone for their help, and MSTRS for coming out and helping me rule out a few things. I should never have to replace those damned spark plugs again :p DB, does that sound like there might have been water getting into the engine somewhere?

[MSTRS]

Water shouldn't have got in by itself. It is possible that your last fill contained some, or ...
Water does not go through jets or injectors very well. It might help to just throw a bit of meths in your tank anyway. Google for an appropriate amount.

[CookMySock]

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.

Go the big hill trick! :clap: The 250 is not too hard to run-start. Just key on, select 2nd, run harrrd, land on seat and ditch the clutch, and then run alongside it with the engine turning over. That will get you fit.

How full is the fuel tank? Maybe time to fill the bugger completely and then go ride it all off! That must be 400kms on that bike! :niceone:

Steve

[Sentox]

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! :niceone:

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

[CookMySock]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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 :laugh:

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]

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]

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]

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?

[MSTRS]

Modern stuff has done away with this basic stuff.

Hyosungs? Modern?
As I said, I'm floundering a bit. A pumper carb is state of the art where my 'skills' lie...

[CookMySock]

OK. So injectors don't have degrees of open?They do, but not the way you are describing it.

The ECU changes the ratio of the amount of time they are open. So, for small amounts of fuel admitted, they open them for 1% of the time and shut them for 99% of the time. Contrast this to a large throttle opening and high revs, where they will be open for more like 75% of the time.

There are a wide range of fuel and air control strategies, but they measure the incoming air charge by either sampling the manifold pressure or by using a mass-aiir-flow sensor in the inlet. They use the throttle position sensor to augment their readings, and for additional tricks like acceleration enrichment (the old throttle pump.)

Consider also, that these days the ECU is going to be loaded with lots of modern software tricks that either just make life easier for the engine, or else run it leaner but safer.

There is lots and lots of home-made EFI stuff around now, and quite a few forums dedicated to learning about it, so there is no shortage of reading material for those so inclined. Search for megasquirt.

Steve

[MSTRS]

Search for megasquirt.
I will never be able to clear that image...:shit:

[CookMySock]

See, here is a 3-D fuel table (or "fuel map") which has Intake Manifold Pressure (Y-axis), RPM (X-axis), and Fuel Values instead of spark Advance (Z-axis).

Don't panic when you first look at it. The colour is "how much fuel to add at this advance, manifold pressure, and revs. Red is more, blue is less."

<img src="http://www.team-integra.net/images/BAEC1978-D3A7-4405-AB2D-2761DC15A96D/articles/tuan/ECU3bar3dignmap.gif">

Steve

[MSTRS]

So...with a faulty temperature sensor, the injectors would not open for the 'correct' length of time? Therefore, letting fuel in, but insufficient for a cold engine?
Pray tell then...why did crash starting get a result?
I'm sorry, but I'm still convinced that there was some sort of physical blockage that cleared as a result of the greater pressures from a rolling start. The engine would be turning over quicker than a starter motor was capable of.

[bogan]

So...with a faulty temperature sensor, the injectors would not open for the 'correct' length of time? Therefore, letting fuel in, but insufficient for a cold engine?
Pray tell then...why did crash starting get a result?
I'm sorry, but I'm still convinced that there was some sort of physical blockage that cleared as a result of the greater pressures from a rolling start. The engine would be turning over quicker than a starter motor was capable of.

Yeh that about sums it up. My guess is crash starting results in a higher rpm, which went to a part on the map which made the mix a lot more palatable. Or as you say it unblocked something somewhere.

[MSTRS]

In some ways, I'm sorry that crash starting worked. Because now all we're left with is guesses. Perhaps we'll never know what the problem was?

[CookMySock]

So...with a faulty temperature sensor, the injectors would not open for the 'correct' length of time? Therefore, letting fuel in, but insufficient for a cold engine?Correct, but it is not clear whether a faulty sensor would falsely indicate "high" or "low" - that could only be determined by experience (sensors usually all fail the same way) or by the technician at the time.


Pray tell then...why did crash starting get a result?
I'm sorry, but I'm still convinced that there was some sort of physical blockage that cleared as a result of the greater pressures from a rolling start. The engine would be turning over quicker than a starter motor was capable of.All of that is only predictable from a statistical point of view - what is more likely or not. I submit, it is unlikely that anything was physically blocked, as this area is very very well filtered indeed. If there was a non-flammable liquid in there it would have acted like it was blocked.

In the end, inside tiny little spaces with no windows no one really knows what happened, and we roll around opinions until we find one that doesn't easily fall over when subject to logic, and that answer's good enough for now. Sooner or later another fault will come along which either adds weight to the hypothesis or blows it out of the water. :wait:

Steve

[MSTRS]

Sooner or later another fault will come along ...

Statistical evidence, plus physical evidence of it's being a Hyosung, suggests you are right.

[CookMySock]

Statistical evidence, plus physical evidence of it's being a Hyosung, suggests you are right.I was meaning, if there really was something broken here, it will resurface shortly.

Steve

[MSTRS]

I knew what you meant. The chance of a dig at Hyosung's reputation was just too good...
That is what worries me when a reason for failure has not been identified. Next time it happens may be somewhere distinctly inconvenient (not in his own driveway) or possibly even dangerous.

[neels]

That is what worries me when a reason for failure has not been identified. Next time it happens may be somewhere distinctly inconvenient (not in his own driveway) or possibly even dangerous.
That's what always worries me when things 'fix' themselves.

It sounds like this could just be a case of a flooded engine though, crash starting shifts a much larger volume of air through the cylinders than turning on the starter motor, and no throttle response for a short time is not unusual until everything sorts itself out.

[MSTRS]

Yea, but this happened over a period of 2 days. You can't tell me that with no further tries, and new plugs, that a flooded engine is still flooded 24 hours later.

[neels]

Maybe?

The injectors will still be pumping fuel into the inlet manifold, if it's cold starting then more than usual. If that extra fuel hasn't cleared trying to start it just adds more to it, even with new plugs.

Anyway, I don't really know, just adding another theory

[bogan]

first step would be to see exactly how the cold starting circuit works, which sensors it uses, how much extra fuel is added etc, hyosungs have been around a while now, should be on the net somewhere.

[Racey Rider]

.... , and the tech needle was going a little crazy, which was strange.


We have had a problem with our carb'ed GT250r race bike like that.
Turned out there is a problem in the Dash unit, which the wiring diagram shows links directly to the front coil.
So the problem for us was not coils. We removed the electronic dash and ran the bike on the open road for 20 minutes without any fault re-ocurring.
Will test at the track in a couple of weeks to be sure.

Racey

[CookMySock]

Yea, but this happened over a period of 2 days. You can't tell me that with no further tries, and new plugs, that a flooded engine is still flooded 24 hours later.This is why I am thinking "water". It would only need a teaspoon full to hiccup it, and there was the comment of a lot of water about in the preceding days. What it would need to clear it is just sustained flow to flush the water though.


first step would be to see exactly how the cold starting circuit works, which sensors it uses, how much extra fuel is added etc, hyosungs have been around a while now, should be on the net somewhere.There is a service manual which extensively details the EFI system including its' service and repair requirements, but it does not extend to describing the prime/enrichen/run engine cycle.

Briefly ;

ENGINE TEMPERATURE
When engine temperature is low, injection time (volume) is increased.

INTAKE AIR TEMPERATURE SENSOR
When intake air temperature is low, injection time (volume) is increased.

BATTERY VOLTAGE SIGNAL
ECU operates on the battery voltage and at the same time, it monitors the voltage signal for compensation of the fuel injection time (volume). A longer injection time is needed to adjust injection volume in the case of low voltage.

ENGINE RPM SIGNAL
At high speed, the injection time (volume) is increased.

STARTING SIGNAL
When starting engine, additional fuel is injected during cranking engine. During acceleration, the fuel injection time (volume) is increased in accordance with the throttle opening speed and engine rpm.

ACCELERATION SIGNAL/DECELERATION SIGNAL
During deceleration, the fuel injection time (volume) is decreased.

TIP OVER SENSOR SIGNAL
When the motorcycle tips over, the tip over sensor sends a signal to the ECU. Then, this signal cuts OFF current supplied to the fuel pump, fuel injector and ignition coil.

OVER-REV. LIMITER SIGNAL
The fuel injectors stop operation when engine rpm reaches rev.

The manual goes on to explain that the sensor voltages should be in the range 0.1-4.6V.

It also comments that there is an idle air stepper motor that controls idle rpm.

I'd better stop pasting stuff out of the manual, as I could go all evening. ;)


Steve

[bogan]

interesting, looking at that (and pulling some thoughts outa my ass) I reckon a faulty air intake sensor could cause both the non-starting and idle-cut problems.

[MSTRS]

interesting, looking at that (and pulling some thoughts outa my ass) I reckon a faulty air intake sensor could cause both the non-starting and idle-cut problems.

See, this is the problem, exactly. There are a number of components (or other events) that can give the same symptoms. If it is a faulty unit somewhere, one expects that it will shit itself again, at a more inconvenient time/place. If it was, say, water that somehow got through the filter traps, then it could also be re-introduced in the future.
One cannot fix what is working, and one cannot prevent a suspicion of foreign influence from recurring.

[CookMySock]

If a temp sensor craps out, usually the engine will still run perfectly ok, just a bit shitty and rich. My guess is, manufacturers wouldn't be brave enough to have a sensor failure lean an engine wayyyyy out. :weird:

But as for it quitting completely, (usually) only an ignition pickup, fuel pump, or wiring (connector) fault or the like will provoke that.


Steve

[bogan]

See, this is the problem, exactly. There are a number of components (or other events) that can give the same symptoms. If it is a faulty unit somewhere, one expects that it will shit itself again, at a more inconvenient time/place. If it was, say, water that somehow got through the filter traps, then it could also be re-introduced in the future.
One cannot fix what is working, and one cannot prevent a suspicion of foreign influence from recurring.

indeed, but you can still test/inspect the components now to get a baseline, and then ensure you have the tools to check/fix if it does happen in an inconvenient time/place

[MSTRS]

indeed, but you can still test/inspect the components now to get a baseline, and then ensure you have the tools to check/fix if it does happen in an inconvenient time/place

If you can get readings of the various electronic components, then carry those readings and the test meter at all times, then sure you can. Would you?
And if the problem was caused by water, where's the evidence? Where did it get in? Was there a particular set of conditions that are unlikely to be repeated just so?

[bogan]

yeh they make some pretty compact multimeters now, I assume hyosungs come with a place to put some tools? just chuck it in there. As for the water thing, I'd just start taking shit apart so I knew where it was likely to end up, then take tools to check or flush that part out if it goes wrong again.

[Sentox]

yeh they make some pretty compact multimeters now, I assume hyosungs come with a place to put some tools? just chuck it in there. As for the water thing, I'd just start taking shit apart so I knew where it was likely to end up, then take tools to check or flush that part out if it goes wrong again.

Or make sure I'm always at the top of a hill :p

I might take you up on your offer to check over some of the electrics when I get back to Palmy, if it's all good with you. I figure the bogan-ness won't be infectious in short doses, right? ;)

[MSTRS]

yeh they make some pretty compact multimeters now, I assume hyosungs come with a place to put some tools? just chuck it in there. As for the water thing, I'd just start taking shit apart so I knew where it was likely to end up, then take tools to check or flush that part out if it goes wrong again.

Better to just get rid of the trouble by selling, and get a different make that you 'know' will be reliable...
I'm not saying this seriously, but who wants to go through life trying to cover all eventualities? It's a tricky one for Sentox, or anyone in that sort of position.

[Sentox]

Better to just get rid of the trouble by selling, and get a different make that you 'know' will be reliable...
I'm not saying this seriously, but who wants to go through life trying to cover all eventualities? It's a tricky one for Sentox, or anyone in that sort of position.

If it weren't for license restrictions, I would probably up and sell it. But until I pass my full, I'd just be losing too much money in the long run. Anyway, between my car, bike, and computers, I'm getting pretty used to stuff breaking by now :laugh: I built a PC once where, I kid you not, every single component crapped itself sequentially. Literally I had to keep replacing parts one at a time until the case was the only original piece left.

[MSTRS]

Basically, this bike has caused you no more grief than any other make might. They all have the capacity to give good or poor service. Stay with what you know. But in order to have full confidence, you need to identify/repair the apparent fault. How, I don't know. unless it faults again.

[bogan]

Or make sure I'm always at the top of a hill :p

I might take you up on your offer to check over some of the electrics when I get back to Palmy, if it's all good with you. I figure the bogan-ness won't be infectious in short doses, right? ;)

or going sufficinet speed to roll to top of next hill?

all good, gimme a pm whenever. The bogan-ness is indeed infectious, but only cos its so awesome :D


Better to just get rid of the trouble by selling, and get a different make that you 'know' will be reliable...
I'm not saying this seriously, but who wants to go through life trying to cover all eventualities? It's a tricky one for Sentox, or anyone in that sort of position.

yeh, good point, I had to do heaps of work on my van and my 250, so for ages I would avoid going far and take heaps of tool if I did, not at all ideal.


If it weren't for license restrictions, I would probably up and sell it. But until I pass my full, I'd just be losing too much money in the long run. Anyway, between my car, bike, and computers, I'm getting pretty used to stuff breaking by now :laugh: I built a PC once where, I kid you not, every single component crapped itself sequentially. Literally I had to keep replacing parts one at a time until the case was the only original piece left.

haha, yeh, best you get a second opinion on electronics diagnostics then :laugh:

[breakaway]

I'm still concerned that his tach needle (a stepper gauge) was bouncing around when trying to start the bike. Shouldn't those systems be isolated of the starter circuit?

I've owned a few EFI bikes, and none of them had any of the problems described in this thread. My first EFI bike was a 2001 GSXR, which was one of the first fuel injected sport bikes (I think they started going EFI in 1999) it had a 'choke', which just pulled on the throttle cable as mentioned. My 2003 GSXR runs at about 1500RPM for about 30 or sec on 1500RPM when fully cold. My 2009 Z750 did the same thinh.

[CookMySock]

who wants to go through life trying to cover all eventualities?Well it would be nice if life was so certain.

Steve

[nosebleed]

Better to just get rid of the trouble by selling, and get a different make that you 'know' will be reliable...
I'm not saying this seriously, but who wants to go through life trying to cover all eventualities? It's a tricky one for Sentox, or anyone in that sort of position.

I guess there won't be an italian bike in his future then? :)

[KIPS powervalve]

Don't by any means try to push start it. My brother did this with his and ruined his CDI. somewhere in the region of $500 for a new one.:facepalm: It will surge it and blow it up. Try starting with the side stand up and lights off. I have a carbed 07 GT250 which has trouble starting if lights are on and/or the stand is down. Something to do with the safety switch which will stall the bike if you try to ride off with stand down.
Hope this helps!

[kmishra]

I know this is an old post but was a solution found to this? I'm having exactly the same issue, bump starting wont start it, voltage / amp / ohms seem fine.
I even tested the ECU with another one and realised that the ECU is showing that the voltage being passed to it is lower than expected :weep: and the bike i was using the ECU from turned on with my ECU on it.

Please help!

[ducatilover]

I know this is an old post but was a solution found to this? I'm having exactly the same issue, bump starting wont start it, voltage / amp / ohms seem fine.
I even tested the ECU with another one and realised that the ECU is showing that the voltage being passed to it is lower than expected :weep: and the bike i was using the ECU from turned on with my ECU on it.

Please help!

How did the ECU tell you this?
If it's true you have a simple issue of voltage drop and can measure for it with a multimeter

[kmishra]

How did the ECU tell you this?
If it's true you have a simple issue of voltage drop and can measure for it with a multimeter

This is what the guys at Peter Stevens geelong told me. I called them today and asked for an update and they said they're going to have to strip the wire spool and cut the wire to find the issue. They're very sure that its either the connector to the ECU or one of the wires going into the ECU.

I'm not sure if its better for me to replace the wiring harness or find the issue at this stage :confused:

[ducatilover]

Find the issue. If it is a harness issue another may do the same thing