MAP Sensor

Discussion in 'Trucks and Trailers' started by JB, Apr 7, 2000.

  1. JB

    JB LawnSite Member
    from NY
    Posts: 92

    The Check Engine Light came on in my 1988 K5 Blazer. I retrieved the code, a 32 (barametric pressure / Map Sensor / EGR). The engine runs fine except for a rich exhaust/fuel smell. Could the Map Sensor really be the culpret? I hate to go out and spend money on a sensor without knowing for sure. Any answers would be appreciated. Thanks, JB
     
  2. John DiMartino

    John DiMartino LawnSite Silver Member
    Posts: 2,555

    try pulling off the vacuum line to the map sensor,make sure you have vacuum to it while its idling,you might have an imploded line or a leak in it,<p>----------<br>John D<br>
     
  3. yortengel

    yortengel LawnSite Member
    Posts: 216

    I would check for a Vacuum leak in the line (like said) also look to make sure that the gasket under the TBI is OK. they have a way of going bad after a little time. GM map sensors are not know for going bad. If you live close to Detroit I've got a new one you can try.<br>Good Luck
     
  4. JB

    JB LawnSite Member
    from NY
    Posts: 92

    Thanks for the info. I found a wire that was disconnected from the EGR crircut, maybe that was the culpret. I checked the EGR and it was working fine and the vaccum lines seem okay. I re-attached the wire and will road test it tommorow.
     
  5. John DiMartino

    John DiMartino LawnSite Silver Member
    Posts: 2,555

    JB,is it fixed?<p>----------<br>John D<br>
     
  6. JB

    JB LawnSite Member
    from NY
    Posts: 92

    John; Seems to be okay, that is, the check engine light has not come on as of yet. It still seems to be running a bit rich though. It has a new oxygen sensor and the motor only has 11,000 miles after a complete rebuild.
     
  7. yortengel

    yortengel LawnSite Member
    Posts: 216

    What makes you think its running rich?
     
  8. JB

    JB LawnSite Member
    from NY
    Posts: 92

    At idle, there is quite a smell of unburned fuel. Almost makes your eyes tear. After I connected the wire to the Map sensor I eliminated the check engine light from coming on. I did discover one thing though; the air intake thermostat flap was not opening. The cold start heat riser tube is missing so the thermostat was not opening the air flap and that seems to be why it was running rich. Now the engine is getting the air it needs to breath. JB
     
  9. yortengel

    yortengel LawnSite Member
    Posts: 216

    Great, Does it still smell funny?<br>Keep us informed.
     
  10. JB

    JB LawnSite Member
    from NY
    Posts: 92

    Problem solved! No more Check Engine Light and the smell is totally gone. Thanks to all for the info. JB
     

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