95 K75 idles but won't stay running

[caseyvr6]

The bike has miles on it, most of which were put there by myself or my father. He owned it since '99 and I purchased it from him about 8 years ago when he bough his K1200LT. The tank was shiny and clean, with minimal granular debris in the bottom which was cleaned out when the pump was replaced. The bike ran like new until this issue and has been maintained by myself on schedule.

The fuel pump had been whining for 2 seasons, at increasing decibels, and when the bike was left out in the rain by yours truly some water got into the tank because I was foolish enough to open the fuel fill cap while there was still water that had not drained from around the edges. I didn't know how much water had entered the tank, but had assumed somewhere near 1/4 cup of rainwater, so I added some fresh fuel and dry-gas and drove it. I made a 30 mile round trip when it started giving issues near home, with the fuel pump screaming at me from inside the tank. The bike would hardly maintain 30 mph and the throttle seemed more of a suggestion than a user interface. I  turned around 2 miles away and crawled home, took my truck to work that day. To this moment the repairs for this issue include a brand-new fuel pump and filter, fully drained fuel tank (removed from bike, inverted, rinsed with fresh fuel and debris cleaned with clean dry rags. With a new pump, filter, clean/clear non-ethanol gas, and the lines flushed with new fluel to the hard-line inside the tank (tomorrow it's going to be pull the line off at the back end of the injection manifold and flush the new fuel that far), there has been no improvement in the symptoms except that the pump is substantially quieter and the bike will at least idle as long as the choke does not go beyond about 35% (cannot go to mid-stop) and the throttle is not touched whatsoever.

I'm thinking the injectors were damaged from the water and aren't functioning properly, or picked up debris at some point during the diagnostic/repair.

I can hear what sounds like one of the injectors, possibly two, but with the bike running I am unable to isolate with much confidence. After flushing the line tomorrow I'm going to try to remove the injectors and turn them on the injection manifold away from the bike so that I can see the individual spray patterns. The easiest answer is that one or more will have a terrible pattern or none at all. Any further suggestions or diagnostic tips are appreciated.

*This post was started new from the "Fuel Pump" post as it's gone beyond the scope of the OP topic*

[Motorhobo]

When you say it idles now, is it a smooth idle or a choppy crappy idle? Maybe it's not a fuel issue at all, but an air issue -- you didn't mention if you checked your crankcase vent hose but that's a good place to start. They're notorious for cracking at the hose clamp and you don't see it unless you pull it off and inspect it.

Might not be a fuel issue at all. Maybe do the ol' propane gas test to see if you've got an air leak somewhere. Maybe you had two issues, fixed the one, and now the other one remains and has gotten worse.

[caseyvr6]

I'll check for air, but the timing seems oddly coincidental. It's not a horrible idle, but certainly not purring either. The reason I'm thinking fuel is I'm not getting the dark exhaust from being too rich and it's truly immediate if I twist the throttle that it kills, regardless of how slight. Plus, like I said, until the water in the fuel the bike was running perfectly.

[K1300S]

easy to check injector operation.  hold tip of long screw driver against injector body while engine is running. put your ear at other end of screw driver. you should hear a rapid clicking.  repeat for each injector.  they should all sound the same.

water does not hurt injectors that fast.  i doubt they are the problem.

propane test...i suspect you have an air leak.  have you done the COMPLETE tune up?  tb adjust, idle adjust, mixture adjust, tps adjust, fuel pressure check, etc?

[caseyvr6]

Have not done the compete tune-up, mostly because I had no problems whatsoever till the water, but that may be smart since I'm due end of season anyway.

[kennybobby]

i think you are on track to pull the injector rail and test for spray from the injectors.  i also think your injectors will be clogged, especially if you had granular debris in the tank, which is the residue of ethanol-fuel-water-aluminum polymers that form in the fuel.  i had a similar water problem and used berryman's solvent to clean and flush my injectors on the bench; they were not squirting dooddly-squat before, now they blast away like josey wales.

[Laitch]

now they blast away like josey wales.

Josey Wales, the Irish rapper?

[Wasserwolf]

Josey Wales, the Irish rapper?

No, he means "Mr. Chain Blue Lightening himself"

[Motorhobo]

Well, you may well have a fuel issue, but if this is a new-to-you bike and you don't know the condition of the crankcase ventilator hose, I really would recommend that you inspect and plan on replacing it in the course of what you're doing now. That hose is made of flimsy rubber that makes a toothpaste tube look sturdy by comparison. But don't take my word for it -- search here for crankcase ventilator hose or z-hose -- it's the weakest part on the K-bike. Fortunately, though, it's cheap.

Good luck!

[Laitch]

No, he means "Mr. Chain Blue Lightening himself"

Oh, that Josie Wales.

[caseyvr6]

Well, you may well have a fuel issue, but if this is a new-to-you bike and you don't know the condition of the crankcase ventilator hose, I really would recommend that you inspect and plan on replacing it in the course of what you're doing now.
Good luck!

I've had the bike for almost 10 years, and my father had it 5 before that, so I'm somewhat comfortable with the history of the bike. That being said, I know I haven't replace the ventilator hose so I'll include that in the fall service since it's been a repeat suggestion. Hopefully I'll have some more details or the "I fixed it" post by tomorrow.

[Laitch]

That being said, I know I haven't replace the ventilator hose so I'll include that in the fall service since it's been a repeat suggestion.

If that crankcase ventilator hose hasn't been replaced in the last few years and isn't faulty, you should convert that bike to a mobile shrine—like a motoLourdes—where riders can bring their ailing bikes to touch yours for healing.

[caseyvr6]

 :hehehe That's funny. Will update, now I'm really crossing fingers

[Laitch]

Will update, now I'm really crossing fingers

Our bikes are the same model year. The only difference really is that yours is located a lot nearer to the Irish Arts Week venue. It just might need a few more days to recover from the vibe.

[caseyvr6]

So... it's not the injectors. I pulled them and had all 3 spraying into a stainless container, and all 3 were nice and even spray patterns just from the pressure the starter can turn to build. I also checked the ventilator hose and, apart from a split just below the hose clamp on the bottom of the air filter housing, it's pliable and seems okay. That being said I'm still going to replace it, but now I'm on to separate diagnostics. I pulled the air filter, housing, and intake pipes thinking maybe a mouse had built a nest or something and all appear clean and in good operating condition. Considering returning to the full service as a means of diagnostics. A suggestion had been made that the airflow sensor could cause similar symptoms, but how's diagnostic possible apart from replacement?

[kennybobby]

What do the spark plugs look like--are they dark and sooty from a rich mixture, or white and ashy from a lean mixture, on the electrode insulator?

Try cranking over with the injectors off and wide open the throttle--does the amount of fuel sprayed seem to increase or not?

The fuel pressure regulator may be stuck open such that the fuel pressure is too low to sustain running above idle speed or when the motor has a load on it.  There is a vacuum line that controls the pressure that is probably cracked if it hasn't been changed recently, it would cause the mixture to run rich.

The jetronic unit could have a cracked solder joint on the injection transistor--swap with a known-to-be-good unit for a quick check, it is very expensive new, but reasonable used ones are available on ebait.

[caseyvr6]

Plugs look good, I'll pull the injectors again to try to adjust throttle. At idle, the exhaust looks/smells normal leading me to believe the mix is at least close to where it belongs.

[Laitch]

Check your fuel filter to be sure you installed it in the correct direction and were not distracted by some erotic reverie during the process. Check your tank vent hose for clogs or kinks. Be sure your ECU plug is on tightly Be sure your throttle body vacuum caps are in place.

[caseyvr6]

Working back; caps are in place (2 of 3 have splits, will replace), ECU plug appears secure, vent hose was blown out when tank was off for cleaning and pump install, filter installed in correct direction (I purchased 2 filters because they were so cheap, both new as well as OE filter all function the same).

[kennybobby]

so it idles, but with the slightest addition of air it stalls => not getting enough fuel to go with that air.

The air flow meter is looking suspect.  The WOT cranking test will give you some insight of whether it is working, since the jetronic adjusts the injection period based upon the AFM signal.

Exercise the flapper valve with a wooden dowel or something to make it move and ensure it is free to move, not stuck for some reason.  Is the AFM an unmolested version, or has it been opened up to horse around with the spring?  Maybe check the connector pins for corrosion and plugged in good.  There is a way to measure the output voltage of the AFM, probably in the lieberry section of this site.

[Laitch]

There is a way to measure the output voltage of the AFM, probably in the lieberry section of this site.

Here's one method from there.

[caseyvr6]

Not sure if it's too soon, but I like you guys. I mean, like like, not just like...  :2thumbup:

[caseyvr6]

so it idles, but with the slightest addition of air it stalls => not getting enough fuel to go with that air.

The air flow meter is looking suspect.  The WOT cranking test will give you some insight of whether it is working, since the jetronic adjusts the injection period based upon the AFM signal.

Exercise the flapper valve with a wooden dowel or something to make it move and ensure it is free to move, not stuck for some reason.  Is the AFM an unmolested version, or has it been opened up to horse around with the spring?  Maybe check the connector pins for corrosion and plugged in good.  There is a way to measure the output voltage of the AFM, probably in the lieberry section of this site.

Actually, it seems that the slightest CHANGE in air the bike stalls. Choking causes stall, as does opening the throttle.


Also, the AFM voltage sounds like a great start except that the pins aren't numbered in any way I've been able to find so unless there's a diagram to show which pin is No. 7, the output numbers are only moderately helpful.

[Laitch]

Also, the AFM voltage sounds like a great start except that the pins aren't numbered in any way I've been able to find so unless there's a diagram to show which pin is No. 7, the output numbers are only moderately helpful.

The whole business is found in this document. Scroll down to it. I'd give you the exact page number but it doesn't have any page numbers.

[caseyvr6]

Nice, thanks.