[yaron112]

Hi,
My K4 started to choke and loose power in the middle of a ride without any earlier symptoms.
I tried to ride it to the garage but after 3 KM it choked completely and stalled.
I towed it to the garage and when we removed the airbox, we saw that the front cylinder manifold was full of fuel.
We cleaned it and the engine started and idled fine but when we revved it up we saw that the manifold is getting overflooded again.

Checking the injector, it looked like it is not constantly opened and it seems to function ok.
We also switched the two injectors but the problem remained on the front cylinder.

Our next ideas is that something is off with the ECU or any of the sensors but in dealer mode there is no error code.

Since I live in Israel and SV1000 is a very rare bike here, so we don't have anyone that is familiar with this bike mechanics plus there are almost no spare parts here

I would appreciate any ideas/suggestion as to how I can find the problem.

Yaron

 

[realshelby]

First thing that concerns me....is that there should be NO way the front intake port is full of fuel! The intake valves would have to stay closed to allow that?
Was it full of fuel or just very wet?
You can test an injector with a test light. That will let you know if the ecu is signaling the injector to pulse....or if it is in a "constant on" state.

 

[yaron112]

First thing that concerns me....is that there should be NO way the front intake port is full of fuel! The intake valves would have to stay closed to allow that?
Was it full of fuel or just very wet?
You can test an injector with a test light. That will let you know if the ecu is signaling the injector to pulse....or if it is in a "constant on" state.

Full of fuel......
Since on idle the bike runs OK, we guess the intake valve is opening.

We tested the injector out of the manifold and it was working in pulses.

 

[Missing Link]

I would agree with realshelby, the intake valves would need to be shut, everytime the engine stopped, unlikely, and for the intake ports to be full of fuel, even to the
bottom of the throttle body, that would take about 200cc of fuel at a guess, and another 150cc or more to get to the butterfly,and by now, your crankcase would
be seriously polluted with fuel as well. So approximately 15km's worth of fuel just sitting there.

Does the bike have a Power Commander or some other mapping device installed ? If so, maybe bypass it temporarily.

 

[yaron112]

Yes there is a lot of fuel there. It is reaching the lower butterfly.

No power commander installed. Only oem ecu.
No tre or any other mod.
In general it is in stock condition only 3/4 Yoshimura installed.

So if i understand you correctly, you are saying we should check the injector again to make sure it is not constantly on.
I will recheck but this was one of our first tests.

 

[realshelby]

There is fuel pressure in the system after you shut off the engine. A bad injector can "leak" or bypass fuel until the pressure is gone. But I cannot see the system holding that much fuel. That engine should hydrolock dumping that much fuel into it after sitting.....
The only thing I can think of is the injector is staying on wide open. Switching the injectors ( stated earlier ) and getting the same result tells me the "signal" to the injector is the path to the problem. My guess would be the ECU. But that is just a guess......

 

[yaron112]

ECU was our next step also even though it seemed really strange that the ecu will have a bad output only for one injector all of a sudden.

The ignition map is a set of ITTT (if I'm not mistaken) so it sounds unlikely (to a computer developer like me) that something will be able to mess with only one chip output that why.

Then again, i never debugged a FI....

Is there any specific sensor for each cylinder? Maybe it got messed up and is sending wring inputs to the ECU.

Anyway, i will start looking for a new/used ECU on eBay.

 

[flashslburg]

I had a broken timing chain, the motorcycle could ride on the rear cylinder, but since the intake valves of the first cylinder did not open, the injector was filled with fuel. I was lucky and the valves didn't bend.

 

[schmidt314]

I have repaired several bikes that have rubbed through an injector wire that caused the injector to just dump fuel into engine.

I have had bikes with ECU failures in the injector circuits, and they all they all kept injectors closed, not open.
-ms

 

[GDCobra]

Maybe I'm misunderstanding the description but

"we removed the airbox, we saw that the front cylinder manifold was full of fuel. "
Sounds like the inlet tract was full of fuel up to the top of the inlet of the throttle body. Is that correct?
Even if the injector was being held open (stuck or triggered) the inlet should drain as soon as the inlet valve opens, Even held constantly open I can't see the injector flowing enough fuel to fill up the inlet tract between inlet valve opening events. And if it did I think the resulting cylinder full of fuel at the next compression stroke would see an engine lock-up and minimum of a bent conrod.

You say
"We cleaned it and the engine started and idled fine but when we revved it up we saw that the manifold is getting overflooded again. "
But did it idle fine on two cylinders or was it simply one cylinder keeping the engine going so it sounded OK?

In short it sounds to me more like the problem is fuel being unable to get out of the inlet tract rather than too much going in. I think @flashslburg may have been onto something with

I had a broken timing chain, the motorcycle could ride on the rear cylinder, but since the intake valves of the first cylinder did not open, the injector was filled with fuel. I was lucky and the valves didn't bend.

I'd at least be investigating this before ripping out wiring or ECU. When the tract is full simply turn over the engine and see it it drains, if not then the valves cannot be opening.
Do it carfully to prevent breaking anything if it does hydraulic lock but it's a simple test which could prevent you going down a complex blind alley.

I know this sounds inprobable but it's not impossible so it could be the solution. And sometimes complex problems have simple solutions

 

[yaron112]

On idle the engine sounds fine and stable so it seems strange to think it is running on 1 cylinder.

Also the exhaust pipe of both cylinders was getting hot so it seems like both are running.

 

[GDCobra]

On idle the engine sounds fine and stable so it seems strange to think it is running on 1 cylinder.

Also the exhaust pipe of both cylinders was getting hot so it seems like both are running.

Well perhaps I'm misunderstanding your description but it seems strange that the inlet tract could be full of fuel (if that is what you are saying) and it is not getting drawn into the cylinder on the induction stroke if the valves are opening. Every time the valves open and the piston drops down the bore it will pull in 500cc of whatever is outside the valves and then try and compress it. If that was only fuel it would empty the tract and you'd have bigger problems than you apear to have. Maybe a photo' would help.
Also seems a simple/cheap thing to check and eliminate.

 

[Missing Link]

On idle the engine sounds fine and stable so it seems strange to think it is running on 1 cylinder.

Also the exhaust pipe of both cylinders was getting hot so it seems like both are running.

Have a look into the service manual (link below)

It is the K3 book , but that covers the K4.... K5 also uses the same book, but there is a supplemental manual with that

SV1000S K3 Manual