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Discussion Starter #1
I have an 02 cbr 600 f4i. When I go to start the bike I get fuel coming out of the exhaust, a pretty steady flow, the bike will start though, but not run real good, the guys at the honda shop said it sounded like the bike needed new plugs. I was just wondering if this sounded right to anyone? I wouldn't think a fouled plug would let gas run out of the exhaust, do you guys think it would, the bike only has 3600 miles on it, so I am out of ideas.:eek
 

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contradiction incarnate
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well, if the plug's not firing/burning the fuel, it's gotta go somewhere

engine's basically an airpump, so out the exhaust it is.
 
K

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Discussion Starter #3 (Edited)
ok, did some work on the bike today, all plugs are firing, but still have some gas coming out of exhaust. The whole story is, had bad gas in tank, but bike ran, went to gas station, put new gas in bike, then it wouldn't start, got the bike home and it barely ran, then gas started coming out of exhaust. thought fuel injector was clogged get new ones, bike run but still have gas coming out of exhaust, but I do have a bolt on the bottom of the gas tank broke, and have to have it welded tomorrow, could it be sucking in air here and causing the problem the bike has 3600 miles on it and I am completely confused any and all help would be much appreciated. I don't think the timing is off, because once I got the bike started today, it ran great, but still have gas coming out of exhaust like it is getting to much fuel. It is fuel injected so I don't know what else to do, have checked for codes and I am not getting any codes.
 

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rain? whats that!
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Are you 100% sure its gas thats getting spewed out the back and not water?

If ALL 4 of your exhaust header tubes are hot to touch, I would completly drain the tank first before putting in reliable gas and trying again.

You havent given us any history on the bike, for all we know it couldve been fished out of the bottom of a lake. Way too many uncertainties.
 
K

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Discussion Starter #5 (Edited)
bought the bike brand new never wrecked or anything like that. I am positive that it is gas, I have smelled it, just went back out and the bike would not start, could it be the ecm? it wouldn't even start with starting fluid. I am really confused as one minute the bike ran, with the help of starting fluid and now it won't run at all, and I am not getting any codes out of the computer, so I have no idea what could be causing this. I have a bunch of guys at work saying it could be the computer, is there anyway to test the computer, without taking it to the shop? The manual says that the ecm could be bad, since I am not getting any codes and the bike won't start, but the bike did start but now it will not, so could this be a computer problem? The day the bike quit running I did have some spark knocking going on but I am sure it was definately the bad gas, but the way it looks it that only 1 fuel injector is pumping gas when the key is turned on, at least I can only see gas coming from one fuel injector, the #2 to be exact. Could this indicate computer problems?
 

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rain? whats that!
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Highly unlikely its the ECU unless youve done something funky to the bikes electrics. I'm assuming the bike is in stock form. If you realy must try the ecu, go to a wrecked bike dealer and ask to borrow one. It should be located under the seat somewhere, simple swap.

I could be wrong but isnt starter fluid a horrible thing to do for a fuel injected vehicle? (could be just for catalytic convertor equipped ones).

You said you pulled the plugs, did they look 'normal' as in no other fouling/deposits besides the unburnt gas?

Were there any plugs that appeared anomalous?

Have you completely rinsed, drained and refilled the tank with GOOD fuel (from a different source).
Have you checked the fuel filter?
 

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Three hour tour guide
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kevinw said:
, but the way it looks it that only 1 fuel injector is pumping gas when the key is turned on, at least I can only see gas coming from one fuel injector, the #2 to be exact.
What do you mean by this????

Did you remove all 4 injectors, let them hang and turn on the key without turning over the bike, and one of them spewed fuel??

If that is what you did that injector is faulty and "leaking"
kevinw said:
thought fuel injector was clogged get new ones,
Does this mean you replaced all 4 injectors??

If the leaking one is new, then maybe..... the ECU could be "firing" it when it is not suposed to, but that'd be .. well not my first guess.

kevinw said:
I have a bunch of guys at work saying it could be the computer, is there anyway to test the computer, without taking it to the shop?
And these "guys" are motorcycle mechanics.... not that I am either, but it is always way too easy to blame the "computer" when you don't know what you're talking about.
 

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Raw gas only comes out the back end if you have a plug or two that isn't firing. It may be that you are not getting a consistent circuit to your coils. When it's misfiring carefully test the temperature of the headers to see if one is cooler than the others. It may be firing but only intermittently. Use a coton towel to protect your fingers but only fold it thick enough to prevent burns but so you can tell the temp within a second or less.

If it was the ECU I would think that the problem would be more consistent. And I agree that it's easy for laymen to blame the computer when it's often the last thing that normally fails. Long before I would suspect the ECU I would be checking my wire harness and connectors for loose or corroded connections, pinches that may be causing shorts and corroded or loose ground connections.
 
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Discussion Starter #9
no i didn't pulll the injectors off, but when the airbox is removed you can see all the way down to the valves and see the gas coming out of the fuel injector, yes the bike is all stock. The plugs all looked the same, nothing real differen't in appearance. And no starting fluid is bad for a fuel injected vehicle, they use the same stuff at the honda place here. Anyway, I am not blaming the computer, as the bike did start and run for a few minutes, but even when it was running I was having gas come out of the exhaust. This is also the same fuel injector that was leaking before i changed the fuel injectors. The spark from the plugs looks pretty good, althought it is more orange than blue, could this be the problem, maybe the spark is not strong enough, or the plugs could be fouled, although I have never seen a fouled plug fire, not saying that it can't happen. and yes I have used all new fuel rinsed the tank and fuel filter seems to be fine. But yet still have gas coming out of the exhaust. Maybe, it is the plugs, too weak of fire not burning off the fuel out the exhaust it comes????? I am out of ideas
 
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Discussion Starter #10
getting ready to for work decided to try to start the bike one more time, with starting fluid. Bike started and ran but had some starting fluid coming out of exhaust, dangerous huh? Anyway, felt all 4 header pipes all 4 are warm, same tempature, so all cylinders are firing, but what could be causing the gas to come out of exhaust, have checked all vacum connections, seems ok. Maybe the fuel pressure regulator??? Once again, I am clueless to what could be causing this, I hate to take it to the shop here because, well let's just say the mechanics here don't always but it back together with all the bolts and nuts they took off.. So any ideas or help will be used, tried and greatly appreciated.
 
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Discussion Starter #11
ok, one last thing, the idle screw was way way out, could this be causing the excessive fuel. I know the idle help control the starter valves, so maybe this is the problem as when the bike started to run for a few it looked like the gas coming out may have slowed down a bit. could this be the problem?
 

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rain? whats that!
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Is it possible that you got a hose mixed up somewhere after you reinstalled the tank?

For my VTR, there were many hoses easy to mix up, I did this at least once.

The idle mixture screw is normally preset at the factory and should not be touched. If somehting has disturbed it, your problems might start from there.
 

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Fuel injected bikes don't have idle mixture screws. Just an idle speed screw.

Kev, have you tried a new set of plugs yet? Orange sparks indicates a problem. The spark should be blue. They are likely fouled. New plugs are cheap in comparison to what you're considering. Try a set before you mess around with anything else.
 
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Discussion Starter #14
No, I haven't tried new plugs yet, but I am going to as soon as the local shop gets them in they say they will have them by Friday, which is ok since the weather here turned off cold. I cannot believe these plugs are $16.60 a piece. The idle screw is kinda what I meant yesterday, They screw was backed way way out, and I didn't know if that could be causing the gas problems????
 
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Discussion Starter #15
at $16.60 US each, you are in the range of iridium plugs. look for a cross reference on iridium plug makers, and go aftermarket for cheap, campared to oem for an arm and a leg.
 
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Discussion Starter #16
checked the old plugs, just to be sure, 3 are firing a blue flame and one is kinda orange, the accidently dropped it, and then tried again started firing blue flame, it so happens that the one firing orange was the one that seems to be letting all the gas in the cylinder when i turn on the key. But I won't know anything for a couple of days, as I will not have the gas tank back until thursday, maybe tomorrow evening, that will be when i know if the bike is still dumping too much gas into the number 2 cylinder as that is what is was doing before. When i turn on the key that cylinder fills up with gas and it doesn't seem like the rest get much gas. But when I get the tank back and on I will get back on here and let eveyone know what happens. I am now positive that it is not the computer as I can pour a little gas into each cylinder and the bike will run, with no codes coming up. but until i get the tank back who knows?
 
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Discussion Starter #17
hmm. Replace your wires, and plugs maybe? If gas is leaking everywhere, perhaps your intake, and or exhaust valves are not sealing properly. you'll wanna do a leak-down test on it as well..
 

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Ridin hard n dirty
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OK...you say you are getting raw fuel out the exhaust but the pipes are warm once you get the bike running???? the amount of fuel that a bike needs to run at idle is so little i find it hard to belive that when it runs it is fuel...the only way you can get enough fuel in the exhaust to spew is when you shut off the bike an injector is still pumping/leaking fuel into the cylinders...if thats the case the plug would come out wet and the cylinder won't run.....when you run the bike how cold is it out side? if you can see your breath the bike will do the same thing once it gets warm and it would start making condensation and it would spew gas smelling water out the exhaust....the fact that you haven't said that it spewed fire leads me to belive that it isn;t fuel filling your exhaust.....check the fuel pressure at the rack and compare it to the shop manual...if the fuel got contaminated it may have plugged up the fuel system....I have seen bikes sit for a year and start just like it was put away yesterday....you must be leaving some information out that would help us help you...think....was the tank full when you parked the bike....did you short anything out if you jump started it....look in the tank with a flashlite is there rust in it.....did you cross your plug wires or injectors....so many other places to check....find a good shop and get them to do a check
 

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back on the street
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why not collect some of the liquid that comes out the exhaust...if it is raw fuel it will burn.....so collect it in a cup, walk out to the road or some other safe place, pour it on the ground and light it on fire.....if it burns it's fuel if not it's water condensation.....
 
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