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does tbi use IAT or CTS?

Discussion in 'The Garage' started by big83chevy4x4, Jan 5, 2006.

  1. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    88 s10 blazer originally with a 4.3, we put a 350 in it and its running rough when warm. i just got the thinking and i may have put the IAT in a collant passage. i can't remember which this uses. anyone know?
     
  2. loafer

    loafer 1/2 ton status

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    All the TBI systems I've owned have used a coolant temp sensor. Never seen an intake temp. sensor on one.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    The cars (Camaro for instance) used an IAT, our trucks didn't.

    Can't say for certain on the S10's, probably dependent on emissions classification. If present, should be in the air inlet track (air cleaner, hose leading to it) or perhaps intake exposed to the incoming air if it exists.
     
  4. JIM88K5

    JIM88K5 1/2 ton status

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    If you used the 4.3 tbi the injectors are not flowing enough fuel...
     
  5. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    not using 4.3 injectors. were actually using 305 injectors. the junkyard we went to get some 350 injectors gave us a tbi unit. just before we went to install it i noticed it said 305 right on it. we went back there and they said they were the same, they just didn't want to give us our money back. we can't find any 350 tbi units around here for a halfway decent price either.
    305 injectors should be enough to run it to atleast 3000 rpm i would think. the problem we have is everywhere once its warm.
     
  6. sled_dog

    sled_dog 1 ton status

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    305 and 350 injectors ARE NOT the same. Different flow rates. Need more fuel.

    All TBI systems(hell all fuel injection systems to my knowledge) use a CTS. I know none of my TBI trucks had an IAT, all the IAT setups I've seen, there is no way you COULD put it in the coolant passage, they usually just push into an intake tube not thread in.

    What about O2 sensors? have headers on it? My Suburban idled rough and broke up a bit through the RPMs when I had long tubes and a single wire O2 on it. Installed a Three wire, it ran like a champ and idled like a dream.

    Lack of fuel will be a factor from idle to high rpms, though I'd expect it to idle decent.
     
  7. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    i know they are different, thats why we went back. but we are forced to run what we have.

    o2 sensor is new, in close to the factory spot with the shorty headers and a modified factroy y pipe.

    it runs great when its cold, lots of power. when you get up into the rpm you can tell its lacking fuel. once it warms up the check engine pops on (code 43 or 44 don't remember, its a lean exhaust anyway) then about a mile later it runs like total crap, acts like its starving for fuel you get on it and it goes somewhat. it doesn't even idle the same when it does this. it quit on us twice while running this way.
     
  8. sled_dog

    sled_dog 1 ton status

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    well when cold it is running in open loop. Not taking any inputs, just running on ECM presets. When it warms up it kicks into Closed loop and takes in inputs(ECT, TPS, O2, Knock, etc). Sounds like one of your inputs is sending a bad signal to the ECM, throwing off fuel. ECTs usually fail cold, they send a false cold signal and never let the car get out of Open loop. My 95 Saturn got 23mpg when I got it because it dumped fuel because the car thought it was cold all the time. I'd look towards the O2 sensor. Have a spare one to swap in? Sounds like it should be getting plenty warm enough. I don't know why the ECM wouldn't try and dump fuel to the rig if it thought it was running lean... I can't see the fuel supply difference being THAT bad. Enough that maybe it would breakup at part throttle and WOT. I don't know.
     
  9. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    the O2 sensor is brand new, we put it in because we thought that was the problem. we also got a TPS low voltage code once we started it up. we replaced it with the one off the 4.3 (same part number) and it went away for a little while, but it still did it and now we are getting the code again. we got a MAP sensor low voltage code on an old but never used MAP sensor. we can't find the old one to put back on it.

    the last time i was there when we ran codes, they were 22, 34, 42, 44 or 43. 22 is the TPS, 34 is the MAP, 42 (forgot to clear the codes after setting the timing) and 43 or 44 lean exhaust code.
     

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