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TBI help...?

Discussion in 'The Garage' started by wforicv, May 27, 2005.

  1. wforicv

    wforicv 1/2 ton status

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    OK guys don't shoot me for this, but my '01 ski boat with a 320HP Chevy 5.7 Indmar TBI (just like our trucks) is giving me fits. I have posted on boat forums but those guys only talk about polishing thier teak ski platforms and crap like that. At the end of last summer, it began running very rich (black, sooty smoke) and started fouling plugs badly. It would run OK (minus the smoke and the bad gas milage) for 1/2 of the day. Then the plugs would get all fouled up and it would become hard or impossible to start. Someone recommended replacing the temp. sensor. I did this and it did not help. I got pissed at the end of the year and put it up with the intent getting it to the dealer over the winter. Well, you guys know the story, summer is here and my boat is still sitting there untouched. Any advise on this? I hate to take it in now, it will be winter again before those idots at the dealership get it fixed (not the mention that boat dealers rip you off 5 times more than the car shops)! If it helps, I have the complete TBI system off my '87 K5 with almost all new sensors (MAP, TPS, etc.). Where should I start?
     
  2. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    Does it have an ALDL like your truck? Can you read trouble codes from it? It could be an injector gone bad (start it cold and watch the spray pattern, it will noticeably reduce as it warms up after 30 secs or so), fuel pressure reg gone bad (easy to put a gauge in line), blocked/crimped return line (check with gauge). Good luck!
     
  3. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    Also check the 02 sensor, MAP sensor, etc :)
     
  4. Thunder

    Thunder 3/4 ton status

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    My guess is 02 sensor. A bad one will put the ECM is bypass mode where it usually runs rich.
    You really should find your ALDL port and scan for trouble codes before spending any money replacing anything.
     
  5. mountain4x4

    mountain4x4 Registered Member

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    o2 sensor won't make it run that badly, MAP, or excess fuel pressure will. My vote is fuel pressure. All we can really do is guess, so thats mine. :D
     
  6. wforicv

    wforicv 1/2 ton status

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    Thanks for the help guys. I am going to mess around with it tomorrow. The good thing is I have a lot of spares to trouble-shoot with.
     
  7. 87GMCJimmy

    87GMCJimmy 1/2 ton status

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    Of the boat FI systems I've seen, none of them run an o2 sensor.

    Mike
     
  8. ryoken

    ryoken Puppy Fabricator Premium Member GMOTM Winner

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    the latest models are running them now... the elbows come with a provision for it...

    that being said, i would doubt it has one.. my guess would be an IAC issue or MAP problem...
     

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