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setting TPS on a 2004 Vmax HPDI 250

S

Solar306

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band new TPS from japan PT# 61A-85885-00-00. the butterflys only turn 20degrees or so, we set the voltage to .5v at idle, but it wont go to 4.5v WOT, at most 2.

So it idles fine but will only go up to half speed.

can set it so it at idle its at 2v and goes up to 4.5V WOT... it idles rough and low end is rough but goes full speed.

Back story was the boat was running rough, bogged bad mid throttle, would die shifting to drive.

replaced the VST filter, the fuel pumps, the injectors, now the TPS.

seems to run fine now and not die shifting but cant seem to dial in the TPS to be .5 idle and ~4.5V WOT.
 
Solar306 said:
band new TPS from japan PT# 61A-85885-00-00. the butterflys only turn 20degrees or so, we set the voltage to .5v at idle, but it wont go to 4.5v WOT, at most 2.

So it idles fine but will only go up to half speed.

can set it so it at idle its at 2v and goes up to 4.5V WOT... it idles rough and low end is rough but goes full speed.

Back story was the boat was running rough, bogged bad mid throttle, would die shifting to drive.

replaced the VST filter, the fuel pumps, the injectors, now the TPS.

seems to run fine now and not die shifting but cant seem to dial in the TPS to be .5 idle and ~4.5V WOT.
Click to expand...
1. Check Mechanical Linkage & Stop Screws (Primary Cause)

  • Disconnect the throttle cable link rod from the throttle body.
  • Manually rotate the throttle valve shaft by hand from hard idle stop to wide-open stop.
  • Target: The butterfly plates should open completely horizontal (~90° from closed). If they still stop at ~20°, inspect the intake sync linkages, roller guides, or stop screws for binding or incorrect adjustments.
2. Verify Remote Control & Cable Sweep

  • If the butterfly valves open fully by hand but NOT via the throttle handle, the remote control cable has insufficient throw, loose plastic trunnion bushings, or incorrect mounting holes on the engine linkage arm.
3. Reset TPS Calibration

  • Re-set the idle voltage precisely to factory spec (0.48V – 0.52V with the throttle plates fully resting against the idle stop).
  • Adjusting the idle baseline up to 2.0V tricks the ECM at high RPM but floods/confuses the fuel map at idle, causing the rough low-end performance you experienced.
4. Inspect the TPS Lever / Shaft Engagement

  • Ensure the internal D-shaft or slotted arm on the throttle body is cleanly engaging the rotor inside the TPS. If the mounting adapter plate or plastic lever arm is bent, misaligned, or installed backward, it will restrict physical rotation.
 
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