FI Light on Solid - Engine Running, difficult to start after throttle body removal

Discussion in '5th Generation 1998-2001' started by daeven, Sep 26, 2021.

  1. daeven

    daeven New Member

    Country:
    United States
    Joined:
    Sep 16, 2009
    Messages:
    25
    Likes Received:
    1
    Trophy Points:
    1
    Location:
    Atlanta
    Map
    Is there anyone around here who is knowledgeable about the fuel injection system and throttle bodies on the gen 5 (1999)? I took the throttle bodies out to replace the thermostat and cooling system hoses. Now that it's all back together, the bike is difficult to start and struggles to maintain idle. After 10 seconds, it smoothes out a bit but the FI light comes on solid. According to the service manual that means the engine isn't running. I've accounted for every tube and connector except for a short tube on the bottom of the throttle bodies. It's too short to get anywhere on top, and the manual doesn't mention it. I assume it is some kind of vent to atmosphere, and I've tried it open and blocked with no difference.

    Does anyone have any experience with similar symptoms or suggestions for things to check?
     
  2. Grum

    Grum New Member

    Country:
    Australia
    Joined:
    Dec 14, 2020
    Messages:
    304
    Likes Received:
    110
    Trophy Points:
    43
    Hi Daeven.
    Guess it's safe to assume that whatever work you've done has accidentally caused the issue so a bit of back tracking might be necessary.

    Firstly the Fi Light being ON - With the side stand Down, the Kill Switch to RUN and Ignition to ON - Does the Fi light flash a code? OR are you saying no matter what the conditions, the Fi Light is Fully ON all the time?

    By what your saying about the engine running perhaps you have either the Vacumm Hose or the electrical connector not on the MAP Sensor. Also the ECT sensor is vitally important for cold engine fuel enrichment making it difficult to start and causing rough idle, so check its electrical connector.

    Bottom line is to check for Fault Codes and that all the Sensors ECT, MAP, IAT have their electrical plugs properly connected and ALL vaccume lines are exactly where they need to be and there are NO vaccume leaks. Another issue is to make absolutely sure that the clamps for the four rubber throttle body joiner boots are tight and not leaking.

    Good Luck and get back to us.
     
    Last edited: Sep 27, 2021
    daeven likes this.
  3. daeven

    daeven New Member

    Country:
    United States
    Joined:
    Sep 16, 2009
    Messages:
    25
    Likes Received:
    1
    Trophy Points:
    1
    Location:
    Atlanta
    Map
    The FI light behaved normally when switching to ON, then would be out when the bike first started. After running (badly) for about 10 seconds the light come on solid while the engine kept running. After reading you post, I tried putting the side stand down and ignition ON. The result is no FI light codes, and then the bike started and ran fine. Several seconds later with the engine running, I get the FI light blinking twice - MAP sensor. I would not have imagined the side stand down makes a difference, but you got me moving in the right direction! I'll get back in there and check it out. I wonder if that extra tube to nowhere is supposed to go on the MAP sensor.
     
  4. daeven

    daeven New Member

    Country:
    United States
    Joined:
    Sep 16, 2009
    Messages:
    25
    Likes Received:
    1
    Trophy Points:
    1
    Location:
    Atlanta
    Map
    Yeah, this is absolutely my problem. More specifically the manual states for two FI blinks "loose or poor connection of MAP sensor vacuum tube." I looked through the service manual and it says nothing about connecting or detaching that tube, but on the diagram on page 5-65, there is a tiny little stub representation of a tube right next to the MAP sensor. There is just enough length in the mystery hose I mentioned that it will reach the MAP sensor. The only question is whether I can manage to get that hose attached with minimal disassembly. I'm pretty sure I got the tank, air cleaner housing and throttle bodies off in 30 minutes last time, but I'd rather not do it again if it can be avoided.
     
  5. Grum

    Grum New Member

    Country:
    Australia
    Joined:
    Dec 14, 2020
    Messages:
    304
    Likes Received:
    110
    Trophy Points:
    43
    There is a very good reason why Honda want the Side Stand Down before Fi Codes are displayed. If the ECM picks up an Active Fault while you are riding it just turns the light to On to alert you, you don't want a light flashing strange codes distracting you while riding. Having the Side Stand down is a known safe, stationary, condition to be at when viewing the flashing codes.

    So with an Fi Code of 2, you may now have an easy fix in making sure the MAP sensor is properly both electrically and vaccume hose wise connected.

    Good Luck. Let's know how you get on.
     
    Last edited: Sep 27, 2021
    daeven likes this.
  6. daeven

    daeven New Member

    Country:
    United States
    Joined:
    Sep 16, 2009
    Messages:
    25
    Likes Received:
    1
    Trophy Points:
    1
    Location:
    Atlanta
    Map
    It's working great now. That vacuum line to the MAP sensor is way to short to connect easily. I extended it a bit with a connector and made my life simpler. Idle was low for a bit, but it cleared up with time. I let the engine warm up in order to verify the new thermostat and hoses and everything works perfectly.
     
Related Topics

Share This Page