GT250R won't start (but cranks)

[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:Me]

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.

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:Me]

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

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:Me]

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 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:Me]

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

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

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 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

[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?