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TBI question

Discussion in 'The Garage' started by nemesis_pyros, Oct 3, 2005.

  1. nemesis_pyros

    nemesis_pyros 1/2 ton status

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    So I've spent a bunch of time on thirdgen.org learning about my winaldl readings and I have a few Truck related questions.

    I'm idling at 1300rpm when the motor is warm. i've tried turning the idle screw down and got it to 1100 or so but this still seems high. I would like to know what kind of idle rpms you guys are getting with your '88 tbi 350's.

    Its also runnning very rich at idle. My blms are pegged at 108. My int value is at 127. The motor is freshly rebuilt with flat tops and a cam thats about 1 step up from an rv cam other thatn that its completly stock. oh and no air pump or cat.

    Thanks for your input.


    Brent
     
  2. HarryH3

    HarryH3 1 ton status Author

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    Pig rich and high idle both point to a possible coolant temp sensor problem. Do you have a scanner that you can attach and see what's going on?
     
  3. dogdaysunrise

    dogdaysunrise 1/2 ton status

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    coolant was at 188.5 and it was in closed loop
     
  4. beater_k20

    beater_k20 Banned

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    wow, dogday, i need to get ahold of you next time i'm working on my junk and run into a problem. how the heck do you know the coolant temp? :confused:
     
  5. nemesis_pyros

    nemesis_pyros 1/2 ton status

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    lol dogdaysunrise and I are working on this thing. He's coming down tonight and we are gonna see what kind of tweaking we can do. Also gonna hook up the laptop to his truck as he was having some issues too. I found a proceedure on thirdgen for resetting the IAC we are gonna try that first see if we can get the rpms down. I also thought I'd note that we didn't find any vacum leaks anywhere.
     
  6. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    I've set my min idle to 600 rpm and let the ECU handle it from there. I did mess with the ECU coolant temp/target idle settings but ended liking stock best.
    I've got flat tops and Edelbrock performer tbi cam and intake.
    One prob I did have was the injectors leaking past the seals and dumping extra fuel in there. Gasket set sorted it out.
    Apart from this age related dodgey gasket prob the truck ran great from the outset with this rebuilt motor. I'm going to do a bit of chip burning for the hell of it but it runs so nice as it is that I don't think I'll get much improvement.
     

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