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leaning out tbi

Discussion in 'The Garage' started by 86chevybanshee, Apr 11, 2005.

  1. 86chevybanshee

    86chevybanshee 1/2 ton status

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    my 92 s10 is running pretty rich, its a 2.8 tbi, i was just wondering if there were some kind of adjustment to make it lean or rich

    thanks
     
  2. Wingnutt

    Wingnutt 1/2 ton status

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    If it started doing it all on it's own, I would highly suspect the O2 sensor, with a second thought going to the fuel pressure regulator. Also don't discount a clogged air filter.

    There is no external adjustment that you can make because the computer controls the A/F ratio from initial cold start to WOT. You CAN adjust it however, but that requires going into the chip and reprograming it.

    Check those things, then give it a good tune up, I'll be willing to bet that will raise the MPG up a good bit.
     
  3. dirtwarrior17

    dirtwarrior17 Banned

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    my money is on the regulator...
     
  4. 86chevybanshee

    86chevybanshee 1/2 ton status

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    well it all started when it decided not start one day. i put a new pickup coil (that was the problem) but i figured why i had the dist. out id put in a new ignition module. i also put a new cap/rotor, plugs and wires, and a coil. i also put a new fuel tank, sending unit, fuel pump and fuel filter. then the exahust after the cat rotted off. i drove it with no exahust after the cat for a day untill my new exhaust came in. and when i put the new exahust on it started running like crap, and it smelt like it was running rich, and also felt like it.

    im gona try a new o2 sensor tommoro and hope thats it, if not i gues a regulator
     
  5. 86chevybanshee

    86chevybanshee 1/2 ton status

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    i put a new o2 sensor in and that didnt help. so i tested the fuel pressure and its at a constant 15 psi, it dosnt fluctuate at all. would the regulator cause it to have that much psi, i thought it was only suppose to be around 9-13?
     
  6. Wingnutt

    Wingnutt 1/2 ton status

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    Hummmmmm, interesting. Since you indicated that after you replaced the exhaust it started running odd. That might be you problem. If it's not welded on, try removing it, put on a section of pipe the proper size out past the cab (to keep the fumes at bay) and see how it does. This sounds like a challanging problem to be sure.
     
  7. blazerguy 90

    blazerguy 90 1/2 ton status

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    Check the coolant temperature sensor (CTS), the computer uses it to set the air fuel ratio as the engine warms up, if its bad it could be telling the computer the engine is still cold even though the engine is at normal operating temperature, that would cause your engine to run rich.
     
  8. Fierospeeder

    Fierospeeder Banned

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    "many things can be wrong" :D


    i would remove that cat. Fix your rich condition first because you will be needing a new cat again.
     

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