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No intake air temp sensor? where could it be?

Discussion in 'The Garage' started by dynoram, Jun 12, 2004.

  1. dynoram

    dynoram Registered Member

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    Well i been working all the bugs out of my recently aquired 88 K5 and the sensor usually located in the intake tube is gone. Wheres the harness for this usually located? I searched and couldnt find anything.Truck idles high and all the other sensors seem to be running fine . I left my haynes manual at work wich doesnt bother me too much because its got some pretty crappy info when it comes to tbi setups. /forums/images/graemlins/1zhelp.gif I tell ya the guy that owned this before me shouldnt be allowed around wire cutters /forums/images/graemlins/doah.gif
     
  2. 4xcrazy

    4xcrazy 3/4 ton status

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    My '89 doesn't have one.
     
  3. dynoram

    dynoram Registered Member

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    Really??
    Well upon further inspection of the snorkel of the aircleaner theres a big hole in the bottom with some kind of shaft broken off inside it. Theres a plastic housing rivited to the snorkel that the broken shaft is attached too. Am i confusing this with something else that was broken off? I read somewhere when changing to an open element air cleaner theres a sensor ya need to relocate so im assuming it should have one?

    /forums/images/graemlins/k5.gif + missing sensor = /forums/images/graemlins/angryfire.gif
     
  4. fortcollinsram

    fortcollinsram 1/2 ton status

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    I ahve NEVER heard of a intake temps sensor on a TBI 350. Only in the Vortec's and stuff. the thing located oin the snorkel that you are talking of is probably the heat riser that helps the motor reach temperature more quickly.

    Chris
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Don't know about the TBI stuff, but it does sound like THERMAC to me too.

    Big flapper valve in the metal part of the snorkel on the air cleaner? Should have a vacuum fitting on it. If so, the temp switch is what you are talking about in the air cleaner housing, and it is strictly vacuum operated, at least in carb applications, don't see why TBI would be any different.
     
  6. k20

    k20 3/4 ton status

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    Earlier trucks have a thermac w/ a vacuum line. The tbi's have a heat riser, its a flexible tube that goes down to the manifold or the header. There is a flap inside of the snorkle (may have been removed if tube is gone) and there is a little thing(dont know term lol) that opens and closes it depending on its temperature. Neither of the tbi's ive dealt with had a vacuum fitting there, or a sensor. Also, how long does it idle high, and what is considered high? I mean a 1500rpm idle or just a little above what it should be? The tbi's idle is controlled up for the first warmup run so it runs cleaner by heating up faster.
     
  7. dynoram

    dynoram Registered Member

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    Yea im a dummy it is the heat riser thats missing . I assumed it was like the tbi found on camaros. Im gonna change the coolant temp sensor hopefully that will cure it.
    Thanks much! As for the heat riser i just dropped an old open element air cleaner i had laying around on it problem solved! /forums/images/graemlins/woot.gif
     
  8. HarryH3

    HarryH3 1 ton status Author

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    I've only seen intake air temp sensors on vehicles that use Mass Airflow Sensors. The temp of the incoming air affects the reading from the hot wire, so the ECM needs to know the air temp to compensate properly. TBI uses a Manifold Air Pressure Sensor, so the incoming air temp isn't as critical.

    First place to start looking to cure a high idle is for any vacuum leaks. Cracked or missing vacuum lines, leak under the throttle body or around the throttle shaft, etc... /forums/images/graemlins/cool.gif
     

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