Fuel Ignition Problem - flooding? - K-Bikes.com - Excellence in Motion
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post #1 of 8 (permalink) Old Aug 8th, 2010, 8:55 pm Thread Starter
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Location: Bellingham, WA, United States
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Fuel Ignition Problem - flooding?

Hello K-Bike Community -

My 1987 k100 RS is out of commission as of this morning. I am out of ideas and wondering if anyone here has any suggestions. Here's my situation.

Its been rainy the last few days, but this morning its finally starting to dry up. I decide to take the bike to run some errands so i wipe the drizzle off the seat (it was uncovered last night) put the choke on, start the engine -- all is as normal. I back the bike up out of my parking spot, rev the engine ----- and it stalls. weird. ok, try to start again -- no go. Starter turns over but engine won't catch.

Throughout a day of troubleshooting, i have not been able to get the bike to start again. Here's what i've noticed.

Gasoline is pooling in my exhaust; it drips from the joints where the exhaust headers meet the mufflers at a good rate upon trying to start the engine. This is not normal.

My fuel pump is "whirring" like it should. My next thought is plugs.

Upon removing the spark plugs, they're soaked (no surprise). I bake them dry, try again. no start. Gasoline pool is back.

I bake the plugs again and test them for sparks -- i notice that two (forget which two) are not sparking correctly, so i buy 4 new plugs and install.

Engine still won't catch -- perhaps it's the coils, i think. I test the new plugs for sparks, and get consistant sparks on both the 1,4 and 2,3 cylinders, proving both of my coils to be operating correctly.

What do you guys think? The bike ran fine yesterday, but today, my gasoline is not igniting. I have a 3/4 full tank of gas, and I doubt enough water could have entered the system to dilute the gas enough to cause this, but who knows? Could my electical system be comprimised?

Please help -- its always appreciated more than i can express here.

Thanks for reading
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post #2 of 8 (permalink) Old Aug 9th, 2010, 1:49 pm
PsyKotic Waterfowl
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Location: Seattle, WA,
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I doubt it's water but if you get enough in there water is heavier than gas and will sink to the bottom.

Pull the spark plugs to see if/which ones are wet from flooding.

Check all connections.

It's not uncommon for the coils to go bad.
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post #3 of 8 (permalink) Old Aug 9th, 2010, 2:15 pm
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I would try popping out the harness that plugs into the computer under the seat and re-set it. I know if it isn't secure the engine will just turn and turn but never catch. I left my bike on the side of the road back when I first got it and didn't know too much about it. A mechanic familiar with the bike told me to press it back in and presto it started up.

I've also heard more than a few stories of the coils going bad. Also, check the connection to the coils. A guy that just did a trip up to alaska and back had a loose coil connection on ADV recently.

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post #4 of 8 (permalink) Old Aug 11th, 2010, 10:58 pm Thread Starter
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Location: Bellingham, WA, United States
Posts: 21

Lukeman -- Good call on the EFI box connection. I too have had that problem before and it was one of the first things i checked. My symptoms are very similar to a disconnected EFI computer.

Heres the update: Yesterday was sunny, so i let the bike dry out while I continued some work on fabricating my coolant temp. gauge cup/ wiring harness. Having let the bike sit over night, i tried starting her up ... with the choke on, i was able to *finally* get the engine to turn over, but it would not idle well without throttle. I kept it running for as long as i could, about a minute, before it stalled for good and wouldn't catch again. I haven't been able to get it started again.

I decided to check out the state of my EFI computer and found some sitting water on top of it. I unplugged my connector, removed the box and shook it -- water droplets came out.

Natually, i opened it up -- i found the insides to be damp, but not saturated. There was some water pooled in the casing and the computer chip was wet, especially where rubber bumpers supported it.

I'm worried about it. I let it dry this afternoon in the sun (still havent reassembled it yet) and examined it more thoroughly. I can't find any noticeable burn marks or oxidization where it an electrical connection could have fried something. I guess that doesn't mean its out of the question though. Here's my one remaining hope:

The bike started yesterday, and ran for a minute. If the EFI computer were truly toasted, this may not have been possible. Maybe having dried out, upon re-installation, my EFI computer will still be operational.

Anyone have experience with this kind of situation? I've always been told not to get electronics wet (which i've always avoided as best i could -- it just makes sense) but i've never had anything like this happen. Maybe its happened to someone else out there. I'll keep this thread updated with results as i find solutions.

Flyingduck - i don't think my coils are bad -- i was able to observe a spark on all my spark plugs. Wouldn't a bad coil mean no spark?

I've also ruled out water in my fuel -- there was half a liter of HEET in my fuel this morning with (still) no luck.
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post #5 of 8 (permalink) Old Aug 12th, 2010, 9:02 am
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An injector could be clogged, and it's allowing free flow of fuel into the cylinders and it's being pumped out the exhaust valve. Try starting the bike with no choke, and hold the throttle wide open. If it starts it will run rough for a while, then smooth out as the excess fuel is burned away. If this is what happens try a can of techron followed by a brisk ride at highway speeds to clean the injectors. Could just be that simple, I hope it is.

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post #6 of 8 (permalink) Old Aug 12th, 2010, 2:50 pm
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I'm surprised you got water inside the ECU, they are usually pretty well sealed up with a ring of silicone around the lid making it a pig to remove. ECU's are very expensive so read on.

What you should have realised is water inside electronics will be contaminated with salts and will conduct, potentially causing more faults when power is applied.

What you should have done is washed out the whole box with methylated spirit or clean de-ionised water, blow dry with an air line, then popped it in mommas fan oven set to a low temperature of about 100 deg. Fahrenheight for an hour.

Then you have to find out why water got inside in the first place and make sure it never happens again.

The ECU contains the drivers that directly control the fuel injectors. Therefore I'm not surprised there was gas pooling if the injectors were permanently held open!

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post #7 of 8 (permalink) Old Aug 13th, 2010, 12:32 am Thread Starter
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Thanks Voxmagna.. very good info. Is de-ionized water a common hardware store product?
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post #8 of 8 (permalink) Old Aug 13th, 2010, 8:45 am
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Originally Posted by jlambert
Thanks Voxmagna.. very good info. Is de-ionized water a common hardware store product?
I`d say....Freddie Meyer! In Canada most drugstores have it, used to be recommended for steam irons to prevent mineral build ups.

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