Recent content by Medic0893

  1. Medic0893

    Driving '91 GM electronic speedometer from a US Shift Controller

    Tayto, can you clarify which wires got to which: The US Shift harness is Purple & Black. Which wire on the original harness goes with which? Thankx
  2. Medic0893

    Engine-Carb Swap: 4L80E Driving me Loco - Upshift Blues

    Well... I gave up! After a year of trying this and that, I took it to someone with an old OBD1 computer. Not a handheld jobber, "The Brick". Turns out the problem is coming from the PCM/TCM. It is just not giving the right commands. Good news is the transmission is working perfectly. So... I bit...
  3. Medic0893

    Driving '91 GM electronic speedometer from a US Shift Controller

    Oh.. Tayto you are correct... You are Awesome
  4. Medic0893

    Driving '91 GM electronic speedometer from a US Shift Controller

    So... For my '92 C2500 (4L80e): When I install the US Shift Quick 2, I splice the trucks original Output Speed Sensor (OSS) wires into the Quick 2 OSS harness (Purple & Black). I ignore the Tan wire that US Shift swears will give me a speedometer signal? I have to agree with Gary: For US Shift...
  5. Medic0893

    Engine-Carb Swap: 4L80E Driving me Loco - Upshift Blues

    Finally got to dial in the Holley TPS. It was off a little. Now its 0.52 to 4.53. It was initially around 0.38 at idle, so not that far off. Results: No improvement, actually seems worse in that it isn't resetting as easily with a rolling restart. Still down shifts and won't upshift without a...
  6. Medic0893

    4l80e and a carb

    What TPS are you using and what are the settings you’re using for the TPS signal?
  7. Medic0893

    4l80e and a carb

    I think I have to disagree, many people have successfully made the transition without a aftermarket TCM.
  8. Medic0893

    4l80e and a carb

    Any issues with downshifting under load at highway speeds, and not up shifting after the load is gone? I have to turn the key off and back on to get it to up shift after every hill… everything else about it works fine on surface streets, only at highway speeds. What TPS are you using? How did...
  9. Medic0893

    Engine-Carb Swap: 4L80E Driving me Loco - Upshift Blues

    Great information and I appreciate it. I did replace the input sensor. Initially I thought it solved the issue but alas no. I didn’t do the output sensor as I read it only controls the Speedo signal which is dead accurate. It’s a 92 so no OBDII port. I have to get a cable for my scan tool for OBDI.
  10. Medic0893

    Engine-Carb Swap: 4L80E Driving me Loco - Upshift Blues

    Appreciate the info. Baseline info: the trans was rebuilt about 20k prior to the carb swap. Always ran and shifted fine. I’m not a big believer in coincidence… Initially I used the HGM Acculink TPS with no luck. I recently installed the Holley TPS but didn’t get a chance to dial it in. It runs...
  11. Medic0893

    Engine-Carb Swap: 4L80E Driving me Loco - Upshift Blues

    welcome… there’s a lot of great info here and everyone is genuinely helpful. When I swapped the TBI for a carb I replaced the entire motor (original crapped out at 295K when I tried to tow something heavy, no complaints). While I was doing that I also did headers, electric cooling fans, true...
  12. Medic0893

    Engine-Carb Swap: 4L80E Driving me Loco - Upshift Blues

    Hey Nick, sorry it took so long to reply: I have no information on the trans rebuild, only that it was done. I’m not familiar with the MLPS, Any insight would be greatly appreciated. Can you give me a list of things that should be replaced? I’m still dealing with the downshifting issue...
  13. Medic0893

    4L80E to TR400 Trans swap 1995 Chevy P30 chassis motorhome

    Sorry I have to agree with the majority: if possible stick with the 4L80e. You said yourself it’s won’t be driven much. Even the high mileage isn’t reason enough to go backwards. Unless you purchased it from your grandmother a TH400 with 70k sounds like a magic bean (Jack). I’d put whatever $$...
  14. Medic0893

    Had to share

  15. Medic0893

    Engine-Carb Swap: 4L80E Driving me Loco - Upshift Blues

    Absolutely happy. Fuel mileage went up and throttle response is awesome. I did a lot more than just the carb. Headers, distributor, electric fans. I will tell you to be careful if you have an electric trans. Getting that right has been a real challenge.
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