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Thread: TPS Troubleshooting. Project intro. Vortec Head Swap on 93 Z71 4x4. Working out Bugs.

  1. #1
    Fuel Injected! MAC's Avatar
    Join Date
    May 2016

    TPS Troubleshooting. Project intro. Vortec Head Swap on 93 Z71 4x4. Working out Bugs.

    Hey guys,

    I thought I would introduce my project and ask for some help getting the bugs worked out.

    Truck is 1993 k1500 TBI 5.7 4L60E with the following upgrades:

    • Vortec 906 heads
    • Speed-Pro CS-1014R cam (2-4/214 @.050 112 LSA)
    • Innovative MTX-L Wideband
    • GM Performance Parts Vortec to TBI Intake manifold (overrated and expensive but good option for emissions)
    • AC Delco EP 381 Fuel Pump
    • Aeromotive Bypass Regulator, P/N 13301
    • Tuning myself with Moates Autoprom

    Currently running BJYL $0D on 16168625 under emulation. I ordered a HDR1 from Moates and it should be here next week. Planning to compare stock BIN to $0D and make changes in $0D as necessary. Long term I am planning to run $0D burned onto a chip that lives on the G1 header. All of this is based on recommendations from Dave at Moates and others here.

    Using A217 $0D TP5 v250 mask that I downloaded from here. I modified the ADX so that the TP dash to show the WBO2 from the MTX-L that is connected to channel 1 on the Autoprom. I made sure that my initial spark advance was set properly (zero in my case) per 93V8S10's comments. I setup the mask to datalog desired AFR instead of battery voltage (per instructions in the ADX).

    Really liking TP and learned a TON in the last few weeks. Thanks to newellshk, jim_in_dorris, and Fast355 for helping a NOOB get his feet under him with the TP software. Also thanks to guys like EagleMark and Six_Shooter who have clearly invested a lot of time and effort here.

    The first bug I am working on is about the TPS. I need help (please) on the following:
    • Throttle Position Gauge does not change on TP dash. The value is defined at loc 0x29.
      • How does this reading impact the operation of the truck, if at all?

    • Interestingly the TPS voltage at 0x10 does change when I push the gas. However it only varies from 0.5 to 3.8. I was expecting the real world to be more like 0v or 0.1 v to like 4.8 or 4.9v
    • Which of these two readings is actually used by the computer to operate the truck?

    Overall, does this mean my TPS is bad?

    Thanks everyone,


  2. #2
    Join Date
    May 2011
    Lakes Region, NH
    It's always a good idea to confirm pressing the pedal to the floor causes the throttle to open fully. With the key on / engine off, manually open the throttle fully, at the TB, and check the displayed voltage. If it's significantly different you should check the throttle cable and pedal for obstruction.

    If the TB check passes use a DVOM to check voltage across the sensor ground and signal wire. If you find low voltage at WOT further checks are needed. Check signal to engine ground, 5V reference line to engine ground for full 5V, and sensor ground to engine ground for voltage difference. If 5V = 5V, Gnd = Gnd, and signal -> engine gnd = signal -> sensor gnd then you likely have a bad sensor.

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