Ok I am pulling my hair out. 1988 Burb Rough idle bad MPG

Discussion in 'Performance & Fuel' started by chad1966, Jun 9, 2010.

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  1. chad1966

    chad1966 New Member

    Ok its a 1988 R20burb 350 TBI. I did a tune up (plugs fuel filter Cap Rotor O2 Sensor) thinking that it would help well it did but not enough. When I pulled the plugs all 8 were black. I knew it was running rich at idle but it must be all the time. When I pull codes they are 22, 33, 45. When I look inside the TBI the Driver injector puddles up inside but I can wiggle the linkage shaft and make that go away. Also when I pull the MAP sensor plug it seems to idle alot better but still misses it seems. Help please. Let me know if I left anything else out that you need to know..
  2. murdog94

    murdog94 New Member 1000 Posts 100 Posts

    Have you looked at the Idle air control valve???
  3. chad1966

    chad1966 New Member

    Oh yeah replaced that too.
  4. murdog94

    murdog94 New Member 1000 Posts 100 Posts

    You take a look at the EGR?? mabey a vacume leak??
  5. chad1966

    chad1966 New Member

    I sprayed some water around the tbi with no change in idle. I pulled the egr and its not plugged
  6. murdog94

    murdog94 New Member 1000 Posts 100 Posts

    OH i did forget have you tested the TPS??? and taken a look at what the codes mean???
  7. chad1966

    chad1966 New Member

    22 Throttle position sensor error (signal low)
    33 MAP sensor circuit error (signal high indicating low vacuum)
    45 Oxygen sensor error (rich condition indicated)

    45 i can see, is 33 because it is idling so low and making low vaccuum
  8. murdog94

    murdog94 New Member 1000 Posts 100 Posts

    Yeah i would run a sweep test on the TPS.. That could be causing 99% of the problem since the TPS is what controls basically everything for fuel etc..
  9. chad1966

    chad1966 New Member

    How do you do that?
  10. murdog94

    murdog94 New Member 1000 Posts 100 Posts

    Take an OHM meter and you put it on i believe points A&B and you will have a resistance reading as you open the throttle.. The resistance should build nice and smooth any jumps or spots where the resitance isnt able to be read by the ohm meter your then your TPS is bad.

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