VFR800 Low Power/Surging

Discussion in '5th Generation 1998-2001' started by carfanatic63, Jun 2, 2016.

  1. carfanatic63

    carfanatic63 New Member

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    Hello all! This is my first post and I dug everywhere trying to find help for my issue. Have a 2000 VFR800 with 52k on it and it has run flawlessly until the rectifier/regulator went out. Replaced that with a VFRness as well and while I was reinstalling everything, I accidently left the kill switch on so the fuel pump primed about 5-6 times and flooded the engine. Managed to get it started but it has been surging and been low on power to where when I take off the bike wants to stall and I have to give it a lot of throttle to even do normal take of speeds. Full throttle blasts it does good once it gets above 3k rpm but then falls on its face around 7-8k rpm. I thought the fuel filter may be clogged so I took off my tank and discovered the tank was covered in rust. I spent the last two weeks cleaning, resealing and getting a new fuel pump/filter for the tank. Got excited to have my bike running right again and reinstalled the tank and the issue still persists. This also only happens once the bike warms up. I checked the plugs and they looked fine (only 1500 miles on them) but I am replacing them anyways just in case. Any other ideas as to what might be causing all of this?
     
  2. Knight

    Knight New Member

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    Hi and welcome to the forum.

    I'm afraid to ask: You said only when warm. So it revs fine when cold? (I wouldn't do this...)

    What is the battery voltage at 5,000 RPM? Secondly, did you run the service manual voltage/impedance tests on the stator? Was the R/R original? If so how about the stator? Just wondering if they are both "end of life", versus, there was a cascade failure caused by a bad battery or a short or such.

    Given the rust issue I am concerned about the last leg of gas flow, the fuel injectors. When cold the engine runs richer which could compensate, but when it is warm and leans out, the gas flow could be insufficient. A recommended service company in the forum is https://precisionautoinjectors.com/pages/about-us.

    Check the resistance from the negative terminal to ground as one test of failed grounds.
     
  3. carfanatic63

    carfanatic63 New Member

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    Yes the bike runs much better while it is warming up to temp. I don't have to give it tons of throttle to take off like I do when it is warm. The exhaust also has a different sound to it than it used to, almost like the bangs in the engine aren't as large as they used to be. I checked the battery voltage on the bike right after I installed the r/r and vfrness and if I remember correctly, they were spot on so I don't think this is a charging issue. Is there anything else I should check besides the injectors? Those were my next step after a new set of plugs. I will mention that I did get about 200 miles of riding in on the bike after I flooded it before the surging and loss of power happened.
     
  4. Knight

    Knight New Member

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    You have to be concise here. Even though you may have done everything perfectly, you should share the spec just so everyone is on the same page. For example, is the voltage in the 14V range at 5,000 RPM when hot?

    Run it hot in the dark. See any arcing among the plug wires?

    I do not understand the flooding incident. The fuel pump can establish pressure repeatedly but it does not deliver any fuel past the injectors. Am I missing something?

    The engine sounding different sounds like a cylinder is not firing. A thermometer like a laser thermometer on each header pipe can identify a dead cylinder. That pipe will be cooler.

    See this thread:

    http://vfrworld.com/forums/showthread.php/26129-1999-VFR800-Unsolved-Misfiring-Problem
     
  5. BWeiss

    BWeiss Johnny Partseed

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    I'd check injectors, fuel pressure regulator and spark plugs. Your engine shouldn't have flooded from the pump priming, that's just building pressure in the fuel lines. If you're sure it flooded, that sounds like a faulty FPR or injector that may be slightly stuck open.

    Plugs are just a good thing to check as well, and could give you a clue to the faulty cylinder.
     
  6. John O

    John O New Member

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    I sure hope you find a better solution, but after my voltage regulator fried my battery, my ignition system got erratic. Eventually I had to replace the control modules. I found used ones, but the expense was not trivial, even then. (This is Honda VTR experience, so maybe it'll never happen on a VFR, but the electrics are probably related.)
     
  7. carfanatic63

    carfanatic63 New Member

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    Thanks everybody for the suggestions. I think after plugs if it still persists, ill do the fuel pressure regulator. I'm pretty sure it flooded since it took forever to start and started with smoke (never did that before or since).
     
  8. carfanatic63

    carfanatic63 New Member

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    Just an update guys, I checked voltage of the battery at idle and 5k and it ran 14.2 volts on both so I don't think that is the issue. I am working on changing the plugs currently (did rear two, doing front tomorrow) but the bike still seems to be hesitant to rev below 3k. Once I get passed 3k it revs fine but then falls flat again on the high end.
     
  9. slowbird

    slowbird Member

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    I'm interested to know if it runs better with the fresh plugs.

    I think we should go back to where you said you "flooded the engine" How do you know it was flooded?

    After you installed the VFRness what happen? Did you try starting the bike and it kept cranking and wouldn't start?
     
  10. BWeiss

    BWeiss Johnny Partseed

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    The flooded engine makes me think he has an injector or 2 out of whack. Even tho the fuel pump primes, nothing should be getting to the cylinder until it's turning over.

    My bet is that an injector is faulty, which floods the engine, but gets enough fuel through to run at mid range, and not enough at high revs.

    If thats the case, 1 spark plug will likely be wet with fuel...
     
  11. carfanatic63

    carfanatic63 New Member

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    Yes that is what happened. Bike would crank but wouldn't turn over and when it did smoke came out of the pipe(not white smoke like oil). I'm cahning the front plugs this afternoon then I will post a picture of the plugs to show what they look like after only 1500 miles of use. One of them was already black and another one looked fine.
     
  12. carfanatic63

    carfanatic63 New Member

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    Alright, changed the front plugs and both were wet and smelled like gasoline. I'm guessing that I have bad injectors on the front. I went to the website mentioned previously for the injectors but didn't see any for the vfr. Does anyone know what would have caused the leaky injectors? The bike has 53k on it and has been old man owned since day one so it is still in great shape (never been down). Also, would yall recommend rebuilding my existing injectors or ordering brand new ones and from where would I do that?
     
  13. BWeiss

    BWeiss Johnny Partseed

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    You're looking for part # 06164-PCA-000

    These look to be the injectors for 99-01 CR-V's as well. New, looks like you'll be shelling out $145-$165 depending on where you look.

    I saw a few used sets of 4 for about $125-$145, claim cleaned and tested and some mentioned a 5 year warranty.

    I saw some refurbed for about $50 each. Just google the part number and look in the shopping section or search the part # in ebay.

    I have no clue how much cleaning and refurb of your injectors run.
     
  14. Knight

    Knight New Member

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    An option is to send injectors out for cleaning.

    Since multiple injectors are are a problem I am concerned that there is no spark up front. Have you run it in the dark yet? You need to run service manual tests on the ignition.

    FYI you could as an intermediary step swap good injectors with bad. If the problem follows the injectors you know that they are the problem.
     
    Last edited: Jul 6, 2016
  15. carfanatic63

    carfanatic63 New Member

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    Hey guys. I have run it in the dark and I didn't see or hear any arching up at the front plugs. And while I was changing them I inspected the boots for tears and they still looked in great shape. What could be causing possible weak spark on the front if that is the case?
     
  16. Knight

    Knight New Member

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  17. slowbird

    slowbird Member

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    Maybe try swapping the places of the injectors to see if the problem follows them?
     
  18. carfanatic63

    carfanatic63 New Member

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    Alright update time. Checked the spark plugs and made sure they were firing only to find out that wasn't the problem so I know it is injectors. (btw, incase anyone is wondering, the vfr800 runs on 3 cylinders). Removed the airbox and looked into the cylinders that had smelled like gas and there was a pool of gas on the valves in one of the cylinders so I know that the injectors have definitely failed. Anyone have a tutorial video or guide with pictures showing how to remove the injectors? The 5th gens are different and much more difficult to do than the 6th gens and I can't find any guides. Any help would be appreciated.
     
  19. Knight

    Knight New Member

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    Do you have the Factory Service Manual which has testing routines? Try vfrdiscussion.com, in the downloads section. (Note that it is currently offline or I would have provided a url to the manual.)

    Two, which cylinder number did you see the gas pooling? And were there multiple? A bad fuel pressure regulator ends up dumping into one of the cylinders (#4 right guys?) that is why I ask. It does make sense that one or more fuel injectors could have been fouled by that rust, but this is one additional item to inspect.
     
  20. carfanatic63

    carfanatic63 New Member

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    I still need to download the service manual. The front left cylinder is the one with the gas in it and the front right cylinder has a little bit as well but not as much. Is it possible that this could just be the fuel pressure regulator? Also, does anyone know where to buy new throttle body boots? I don't see any new ones on ebay.
     
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