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Choked out 90

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Motoronbrain, Apr 8, 2002.

  1. Motoronbrain

    Motoronbrain Registered Member

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    I just recently bought a 90 after selling my 71 blazer, guess I could not live with out one. Any ways, my question for you quys is that my blazer is running way rich as if the choke is on. It has the throttle body. I checked my codes and got the TPS code. I have replaced it and there are no more codes. Put fresh plugs in, got it to fire up, and the sme thing is going on. Black soot and fouled my plugs. What is wrong with my blazer? I need help before I go and do something stupid.

    thanks.
     
  2. TJS

    TJS 1/2 ton status

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    The TBI base gaskets usually fail. With engine running spray some carb and choke cleaner at the base of TBI. If idles picks up then replace the gasket. They are cheap too.
     
  3. Motoronbrain

    Motoronbrain Registered Member

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    Know I have changed the MAP sensor and the sensor on the TBI, can't rember what it is called the TBI gasket and new plugs. It still is getting to much fuel. I have tried everything I know. How hard is it to change over to carb, with all this computer stuff anyway. Any help is greatly appriciated.
     
  4. Might check your fuel pressure regulator on the TBI? Then check the IAC (idle air control) motor? Is it just rich when you start it up, or is it rich all the time? Make sure both fuel injectors are "spraying" fuel and not dribbling fuel in. My buddies fuel injected 350 had 1 bad injector and it was dumping too much fuel in, causing it to run super rich, bad idle, and crappy gas mileage.
     
  5. Motoronbrain

    Motoronbrain Registered Member

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    This is running rich all the time, I can't even drive it! It looks like they are spraying but don't know what they would look like if was dribbling. The idle is real high, I have checked for vacuum leaks and have found none. I am just plain frustrated with it. I don't want to dump a lot of money buying all these sensors so I thought I would ask the pros first.
     
  6. If it is running rich all the time and it idles really high, then I'd check your TBI base plate gasket. I had to change a few of them on rigs that came into the auto shop where I worked. It definitely sounds like you've got a lean condition from a vacuum leak causing the computer to tell the injectors to dump more fuel? If the spray from the fuel injectors isn't a fine spray mist, and it is just kinda dribbling into the venturi, then you have an injector problem. Let me know.

    Later.
     
  7. Motoronbrain

    Motoronbrain Registered Member

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    Well I am frustrated, lost focus and plain mad. I have chaged MAP,Fuel Pressure Regulator, Throttle Position Sensor, Base Plate Gasket, and it still looks like enough fuel flow for a Top Fueler. I need help. Ready for the things I understand, Carburetor!!
     
  8. Thunder

    Thunder 3/4 ton status

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    If yur running waty rich and not getting a code 45 (O2 sensor detecting rich exahust ) It may be the O2 sensor is bad. A bad O2 sensor can cause it to run rich. But usually the check engine light comes on. But not in every case. A non functioning 02 sensor will cause the computer to go into override mode (or limp home) It then runs on pre programed settings which are usually rich in fuel. its the computers way of telling you to get it fixed.
    If you had a good scanner it would help a lot because it gives the readings from all the various sensors and its easy to tell when one is not functioning.
     
  9. Motoronbrain

    Motoronbrain Registered Member

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    I am not getting any codes and this isnt just a rich problem,it will not run without fresh plugs in it, and you cant drive it, it is like it is always floored. That is how much fuel is going in to the motor. As soon as I get it started you have to floor it and it still fouls out plugs.
     
  10. AJMBLAZER

    AJMBLAZER Better to be lucky than good. Premium Member

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    Are you sure the MAP sensor is plugged in? When I put a 1" throttle body spacer on my TBI 350 we forgot to plug it back into the TBI and the thing ran like sh$t. Like a badly tuned big block with a drag racer lopey cam. Had to give it gas just to get it to start, blew black smoke, drove bad for the first 15 minutes or so, only got like 6mpg./forums/images/icons/tongue.gif Found the MAP sensor plug thingy hanging behind the engine, plugged it back in, and WHALLA!
     
  11. Motoronbrain

    Motoronbrain Registered Member

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    I will check it out thanks
     
  12. Motoronbrain

    Motoronbrain Registered Member

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    What plug are you talking about? the plug for the map sensor is plugged in and the vacuum line from the map to the TBI is plugged in. Is there supposed to be another line from the MAP to the TBI?
     

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