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Discussion Starter #1
My bike has been running really rich I talked to some one who told the 02 sensor was probely bad, well I replace it and that was not the problem. so I was running the bike and the second cyclinder was not getting hot like the rest of them ,so I pulled the spark plug and the plug it was soaked I am getting spark. So can the injector be stuck open? or is the computer telling it to stay open. Just installed a new battery and did the throttle two times to reset it.
 

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When you say soaked I presume you mean with gasoline? Certainly that would indicate a failure of that specific injector OR an overall condition causing an extra rich mixture and that cylinder simply flooded out. All the injectors receive the same pulse signal from the computer. They do not individually adjust. On automobiles with a V6 or V8 there are two O2 sensors and each bank is individually adjusted for mixture but this is not the case on the inline four cylinder. The O2 sensor provides the feedback signal which adjusts all four of the injectors at the same time.

As a suggestion, turn the cycle ignition to on and you can hear the fuel pump charge the fuel rail system for about 1 to 2 seconds. With the suspect plug removed and a small LED penlight you could look through the spark plug hole and have someone turn the ignition to the on position. If the injector is stuck you may be able to see fuel squirt into the cylinder. I can't be certain but I would think that the fuel pump may also cycle back on if this were the case so if you turn the ignition to the on position and the fuel pump cycles off and on or runs constantly without the cycle being started then that (leaky or stuck injector) should be the problem.

If that's not the issue then you are likely looking at an issue with the ambient air temperature sensor, engine temperature sensor, or one of the other inputs which vary the fuel mixture as the engine operating conditions fluctuate.
 

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Sorry, the short answer is no. The computer cannot tell the injector to stay open. It can only vary the pulse width which is a short electrical burst sent to the coil in the injector. The computer has operational parameters programmed in and the time each injector is open is microscopic. If it's stuck open it is broken or partially clogged.
 

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There may be one more possibility: I'd have to check the wiring diagrams, but on 99% of fuel injection systems, the control unit grounds the injector(s) to turn them on. If the wire between the injector and the control unit shorts to ground, the injector will stay on and flow fuel as long as the fuel pump is running.
How is the oil? Is the level high? If so, the fuel is probably washing down the cylinder and contaminating the oil. Check to see if the injector is mechanically or electrically staying open, change the oil and filter, remove the plug and give the cylinder a shot of oil before installing the new spark plug and starting the bike.
 

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Discussion Starter #6 (Edited)
The oil was just changed last week when I brought the bike out of hibernation the levels so far are fine. I have only ridden the bike 60-70 miles and when I stopped It was smoking (really rich gas) I thought that maybe it was the stabil I put in the gas. I will try checking to see if the gas is dripping in as recommended. Also if the gas is not dripping or spraying is it possible that it can not get enough air when it is running and cause the problem? I put a new air filter in also. by the way it is a 01 K1200lt I really want to thank you all for the help!!
 

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All the grounds of the injectors are tied together and go back up to the Motronic for thier "open" signal.


I would just install new plugs and have another go at it.
 

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Discussion Starter #9
OK I just hooked up a 1/4 inch poly air line with a barbed fitting held it with my hand against the injector put 15LBS of air pressure to it and air went through the injector. Am I correct in thinking and I am pretty sure I am that there should be no air going through the injector with no electric going to it. Just so you know
 

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Unfortunately. If replacing the spark plug doesn't help. I'll have to disagree with some of the opinions placed here.


Yes a fuel injector can stick open..It's a mechanical device and some crud can cause it to stick open. Or Age. They can warp with excessive heat.

Yes the computer can cause the injector to stay on all the time.
When the computer fails the transistor that controls the injector shorts to ground.
Injector is on all the time. I could pull the lead off the injector and when the cylinder cleared enough it would fire a few times then start missing again. Then plugging the injector back in caused the cylinder to run until it flooded out.

I'd say pull the plug, turn the ignition on and look for fuel. Then unplug the injector and see if it stops. This should tell you if it's the injector or the computer. Or none of the above and you just need a new plug...

Good Luck

John
 

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JPSpen, you had a single injector stick open from a controller fault on a multiple cylinder engine? I'm just curious. The ground fault makes sense to me but I'm curious if someone has seen that where it only affected a single injector.
 

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muddawg said:
OK I just hooked up a 1/4 inch poly air line with a barbed fitting held it with my hand against the injector put 15LBS of air pressure to it and air went through the injector. Am I correct in thinking and I am pretty sure I am that there should be no air going through the injector with no electric going to it. Just so you know
You should get no flow at all with the injector off. They seal against fuel flow at around 50-60 PSI so that absolutely NO fuel leaks by. If you can get air flow, then the injector is definitely stuck.

A quick test would be to swap that injector with one of the others and do a short engine run to see if the problem changes cylinders with it.
 

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grifscoots said:
If the injector stayed on, wouldn't you get a hydro lock and a rather nasty stop?
grif is correct. a leaking inj. can easily "lock" a cylinder or worse bend a rod, doesn't take much. the safest thing to do is pull the plugs before you try to start it again and crank it over to clear the cylinder. it won't lock when it is running or when shut off for short periods of time but over night enough fuel can leak in to do some damage.
john
 

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Welcome to the site :wave

If you can't figure it out, Mathia's Cycle in Dover can probably do it for you. They are way cheaper than any other dealer around here.
 

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Discussion Starter #15
Got-er-done!! it was a leaking fuel injector filled the oil with gas replace the injector and changed oil runs great, weekend will not be here fast enough. Thanks for your input from everyone. One little story to tell I called all seasons BMW in Wooster Ohio they told me that they could not get me just one injector they wanted to sell me all four with the fuel rail $940.00 I thought that was B.S so I called Mathis BMW in Dover Ohio, they said they did not have one in stock but could have me one the next day $125.00. Moral of the story well I am sure you know. Good day to everyone.
 
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