ARCO TP001 Throttle Position Sensor — MerCruiser, Volvo Penta & OMC Stern Drive

ARCO TP001 — Throttle Position Sensor

The throttle position sensor (TPS) is a precision input device for your engine's electronic control module (ECM). It reports throttle plate angle in real time, enabling the ECM to calculate accurate fuel delivery, manage idle speed, and coordinate smooth acceleration. A failing TPS typically causes rough idle, hesitation on acceleration, erratic RPM at cruise, or an active fault code — symptoms that can be difficult to trace without isolating this sensor first.

ARCO's TP001 is a direct OEM-replacement unit built to factory specifications for GM-based MPI inboard engines. It fits the factory mounting location with no modification, uses the stock wiring harness connector, and restores accurate ECM signaling from first start.

Part Identification

• Part Number: TP001 | Store SKU: 57-TP001
• Brand: ARCO Marine
• Official Product Type: Throttle Position Sensor (TPS)
• Supersedes / Cross-Reference:
  • MerCruiser OEM: 803148
  • OMC Stern Drive / Volvo Penta OEM: 3855296
  • Sierra Marine: 18-7757
  • CDI Electronics: E13-0008
• Replaced By: No known supersession — TP001 is current production

Compatible Applications

• MerCruiser — GM 5.7L MPI (1997 and up)
• MerCruiser — GM 6.2L MPI (1997 and up)
• Volvo Penta — GI series, GM-based MPI (1997 and up)
• OMC Stern Drive — GM 5.7L & 6.2L MPI (1997 and up)

Verify serial number and model year against your engine's service manual before ordering. MPI (Multi-Point Injection) engines only — not for carburetor or TBI applications.

Engine Family & System

• Engine Family: GM V8 — 5.7L (350 CID) & 6.2L MPI
• System: Electronic Fuel Management / Throttle Body Assembly
• Diagram Position: Mounted on the throttle body assembly, typically at the port (left) side of the intake. Refer to your engine's exploded parts diagram — throttle body section.

Dimensions & Weight

• Weight: Approx. 120 g (estimated — consistent with OEM unit)
• Mounts via two-screw flange to throttle body; no modification to housing required

What's Included

• 1× ARCO TP001 Throttle Position Sensor
• OEM-style wiring harness connector (plug-and-play)

Related Parts

• Arco IG001 Ignition Sensor — MerCruiser Thunderbolt IV & V
• Arco IG008 Ignition Coil — MerCruiser V8 Delco HEI
• Sierra Marine Distributor Cap 18-5362

Service Interval

The TPS is not a scheduled-replacement item. Replace on failure or when diagnostic scanning confirms TPS voltage is out of specification (typically <0.2V or >4.8V at rest, or erratic signal under throttle sweep). Inspect at each annual tune-up as part of sensor harness and connector review.

Technical FAQ

Q: How do I know my TPS has failed?
A: Common indicators include rough or hunting idle, flat spots during acceleration, sudden RPM surges at cruise, or a stored fault code pointing to throttle position input. Confirm with a scan tool — TPS voltage should sweep smoothly from ~0.5V at idle to ~4.5V at wide-open throttle.

Q: Do I need to reset the ECM after installation?
A: Clear any stored fault codes after installation. Most GM-based MPI systems will relearn idle and throttle position automatically after a short drive cycle. Refer to your engine service manual for the specific relearn procedure.

Q: Can I install this without removing the throttle body?
A: Yes. The TP001 mounts externally on the throttle body with two screws. Set the throttle plate to the fully closed position before tightening to ensure correct baseline calibration.

Parts Desk Insights

Best Use Case: Reach for the TP001 when a customer describes hesitation, rough idle, or RPM instability on a GM-based MPI inboard and a scan tool points to a TPS fault code or erratic signal voltage. This is a clean, direct swap — most customers can handle it with basic hand tools. Verify the engine is MPI (not TBI or carbureted) before confirming fitment.

Common Issues: Customers sometimes order this for non-MPI (carbureted or TBI) GM engine variants — confirm the engine designation includes "MPI" before purchase. Post-install rough idle is almost always resolved by clearing fault codes and completing a throttle relearn cycle. If symptoms persist, advise inspecting the throttle body bore for carbon buildup before further diagnosis.