IAC/TPS

Discussion in 'VeloSyTy Chip Support for Syclone/Typhoon' started by ppress79, Nov 24, 2018.

  1. ppress79

    ppress79 Member

    Hi eric, My truck has been down for some time and am now re-tuning. The instructions call for 30-40 iac and tps .60-.90. The best I can get is 85 IAC and .51 TPS. i have followed the service manual proceedure for troubleshooting both and they work correctly. If I raise the TPS any farther to try to get the correct TPS and lower the IAC it starts to manually raise the idle. Was wondering if a large cam (.547/232@.050/114LSA) can be be the reason I cannot get the correct numbers?

    Phil
     
  2. EricM

    EricM Administrator Staff Member

    Raise the TPS (using the throttle stop) with the ignition off. Then start the engine and let it settle. See if that helps. You might even need to drive around a little bit.
     
  3. Typhoon0627

    Typhoon0627 New Member

    I have this exact problem as well.

    I tightened the throttle stop screw with the engine off, and got the TPS volts up to .6, but when I start it up, the MAP goes down to 25.6, IAC goes to 80, my TPS% is at 3.5%, which then raises the idle up to 1650, and it doesn't correct and come back down. I tried this with the truck off after I warmed it up, tried driving it around after, even pulled the ECM fuse to let the chip reset and then drove it around town for 20min so it could re-learn everything, and no change. If I back the throttle stop screw out til TPS% is at 0%, the TPS volts go down to .49, IAC is 41, and MAP is 29.5.

    A couple other issues I have are when I'm stopped (in drive or park), if I barely tap the gas like TPS 7.5%, my RPMs dip a couple hundred, AFR goes down to 10.3 and then the RPMs and AFR go back up. Like it's getting too much fuel, flooding, and then recovering.

    I'm also having a weird issue which might also be related. If I have the truck in D, and take my foot off the brake from a stop light, the truck will slowly accelerate enough for it to shift into 2nd without ever having touched the gas pedal. Yesterday I was cruising at 45mph in 4th/OD with my foot off the gas. Other times, if I take my foot off the gas as I'm decelerating to a stop sign, the RPMs will randomly go up as I'm slowing down, and then they'll eventually come down under 1000 as I come to a stop. I've adjusted the TV cable, and replaced all the vacuum lines with silicon lines, and gone through them more times than I care to mention, to make there aren't any leaks.

    Could all this related as a result of my baseline settings being off, and the manual saying it needs to see 25-30 IAC, and .6 TPS volts, and 30-40 MAP to work right?
     
  4. EricM

    EricM Administrator Staff Member

    It's not critical that the TPS is .60. In the instructions, I was simply noting that typically its in the .60-.90 range, but it's fine at .49 if everything is running ok there. It's mainly the TPS % that we're concerned with. It needs to be zero or under 1% when your foot is off the gas, or the IAC and other things may not work right.
     

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