Product Overview
The COGENG 716/D2727 is an inductive engine speed sensor (crank speed pickup) engineered as a direct aftermarket replacement for a wide range of JCB construction machinery. It monitors rotational movement of the engine's flywheel ring gear or timing gear, sending accurate pulse signals to the tachometer, ECU, or engine hour meter. It is cross-referenced with OEM part number D2727 and other associated codes.
COGENG Part Code: GG716 / D2727
Sensor Technology: Passive magnetic induction (no external power needed for signal generation)
Electrical Specs: Designed to match JCB original resistance and output voltage parameters
Build Quality: Oil-resistant potting compound, reinforced cable exit, and corrosion-resistant metal body
Equipment Compatibility
This sensor is built to fit popular JCB machines, particularly those across the 3CX, 4CX, Loadall, and JS excavator lines. Compatible series and models include:
Backhoe Loaders: JCB 3CX, 4CX (various generations – verify vintage)
Telehandlers: JCB Loadall series (multiple engine variants)
Tracked Excavators: JCB JS series (e.g. JS130, JS160, JS200, JS220, and other JS models sharing this pickup design)
Additional Fitment: Also suits certain JCB wheel loaders, skid steers, and diesel generators using the same engine sensor architecture
Always confirm the OEM part number stamped on your original sensor or listed in your machine’s parts catalog before purchase.
Decompose pictures
| Reference Number | Part Name | Description & Function |
|---|---|---|
| 1 | Sensor Body (Iron Housing) | High-strength iron/steel cylindrical main body with precision-machined mounting flange. Provides robust physical protection and accurate alignment with the flywheel ring gear. |
| 2 | Magnetic Pickup Sensing Element | Sealed electromagnetic inductive coil at the sensor tip. Detects passing flywheel ring gear teeth and generates an AC voltage pulse signal proportional to engine RPM. |
| 3 | Rubber O-Ring / Sealing Gasket | Oil and temperature-resistant Viton/Nitrile rubber seal integrated on the mounting flange. Prevents oil leakage from the flywheel housing. |
| 4 | Electrical Connector Socket | Industry-standard sealed 2-pin or 3-pin connector interface. Accepts the Komatsu wiring harness plug for speed signal transmission to the engine controller or tachometer. |
| 5 | Terminal Pins | Gold or tin-plated brass conductor pins inside the connector socket. Provide corrosion-resistant, low-resistance electrical continuity for accurate RPM pulse signals. |
| 6 | Internal Induction Coil | Precision-wound copper coil encapsulated within the sensor body. Generates a sinusoidal AC voltage signal whose frequency is directly proportional to engine speed. |
| 7 | Mounting Flange & Bolt Hole | Precision-machined steel mounting bracket with bolt hole. Allows secure fastening to the flywheel housing at the correct air gap distance from the ring gear. |
| 8 | Connector Locking Mechanism | Integrated locking tab or spring retainer clip on the connector socket. Ensures the mating harness plug stays firmly engaged under severe engine vibration. |
Parts list
| Item | OEM Reference No. | COGENG Part No. | Description | Qty |
|---|---|---|---|---|
| 1 | 716/D2727 / 716-D2727 / 716D2727 | CG-716-D2727 | Komatsu Revolution Speed Sensor — Complete Assembly (Iron Body + Rubber Seal) | 1 |
| 2 | — | CG-SEAL-716 | Replacement Rubber O-Ring / Sealing Gasket for 716/D2727 Sensor | 1 Set |
| 3 | — | CG-CONN-KM-2P | Replacement 2-Pin Wiring Harness Connector Plug with Terminals & Seals | 1 (Optional) |
| 4 | — | CG-SPACER-SS-KM | Sensor Air Gap Adjustment Spacer / Shim Kit for Komatsu Engines | 1 Set (Optional) |
Safety Precautions
Avoid Rotating Parts: Keep hands, tools, and clothing clear of belts, pulleys, and flywheel openings while the engine is running or cranking.
Electrical Isolation: Disconnect the battery before unplugging the old sensor to eliminate the risk of accidental shorts.
Burn Hazard: Engine surfaces stay hot after shutdown – allow adequate cooling time or use protective gloves.
Wire Routing: Secure the sensor cable away from exhaust manifolds, turbochargers, and steering linkages to prevent heat damage or cuts.
Magnetic Field Awareness: The sensor tip contains a permanent magnet. Keep at a safe distance from medical devices like pacemakers and avoid direct contact with electronic storage media.
Cross-Reference Compatibility Table
| Brand | Compatible Part Number | Typical Engine Models | Notes |
|---|---|---|---|
| COGENG | CG-716-D2727 | S4D102E, S6D102E, SA6D140, SA6D95L | Primary COGENG Part Number |
| Komatsu (OEM) | 716/D2727 | S4D102E, S6D102E, SA6D140, SA6D95L | Direct OEM Equivalent — Slash Format |
| Komatsu (OEM) | 716-D2727 | S4D102E, S6D102E, SA6D140, SA6D95L | Direct OEM Equivalent — Dash Format |
| Komatsu (OEM) | 716D2727 | S4D102E, S6D102E, SA6D140, SA6D95L | Direct OEM Equivalent — Compact Format |
Installation decomposition diagram
| Step | Action | Key Component | Specification / Torque Guideline |
|---|---|---|---|
| 1 | Safety Preparation | Komatsu Engine & Electrical System | Park machine on level ground. Shut off engine, remove ignition key. Disconnect battery negative terminal. Allow engine to cool completely. |
| 2 | Locate Sensor | Existing Sensor Position | Identify the revolution sensor location on the flywheel housing. It is typically mounted radially over the ring gear. Clean the surrounding area thoroughly to prevent contamination. |
| 3 | Electrical Disconnection | Harness Connector (Item 4) | Depress the locking tab and carefully unplug the wiring harness connector from the old sensor. Inspect terminals for corrosion, moisture, or physical damage. |
| 4 | Remove Old Sensor | Old Sensor (Flange Mount) | Remove the mounting bolt securing the sensor flange. Carefully pull the old sensor straight out from its bore. Note and retain any shims or spacers present for air gap reference. |
| 5 | Inspect & Clean Mounting | Flywheel Housing Bore & Ring Gear | Clean the sensor mounting bore with a lint-free cloth. Remove all old seal material, debris, and oil residue. Visually inspect ring gear teeth for damage or excessive wear. |
| 6 | Check & Set Air Gap | Sensor Tip & Ring Gear Teeth | Install the correct shims or spacers as needed. The air gap between sensor tip and ring gear teeth must match OEM specification (typically 0.5–1.5 mm / 0.020–0.060 inch). Verify with a non-magnetic feeler gauge. |
| 7 | Install New O-Ring | Rubber Seal (Item 3) | Fit the new lubricated O-ring onto the COGENG sensor body. Lightly coat with clean engine oil. Do not use liquid sealant, RTV silicone, or PTFE tape. |
| 8 | Sensor Installation | COGENG Sensor (Item 1) | Carefully insert the sensor into the mounting bore until the flange seats flat against the housing. Install the mounting bolt and tighten to 8–12 Nm. Do not over-torque — this may crack the sensor flange. |
| 9 | Electrical Reconnection | Harness Connector | Firmly push the connector onto the sensor socket until the locking mechanism produces an audible click. Tug gently to confirm secure positive engagement. Route the harness away from hot or moving parts. |
| 10 | Final Verification | Battery, Engine & Instrument Panel | Reconnect the battery. Start the engine and verify the tachometer displays correct and steady RPM reading. Check for any active fault codes. Monitor for oil leaks around the sensor flange. |
Follow these steps to correctly install the COGENG 716/D2727 speed sensor. The engine must be switched off and cool.
1. Locate the Mounting Port
Find the sensor mounting location – usually on the engine flywheel housing or timing case, positioned to face the ring gear teeth.
2. Disconnect & Remove Old Sensor
Unplug the electrical connector. Loosen the lock nut, then unscrew the old sensor fully. Note the depth before removal if possible.
3. Prepare New Sensor
Inspect the COGENG 716/D2727 sensor tip. It should be clean and free of debris. Compare the thread length with the original part to confirm a match.
4. Set the Air Gap
Thread the new sensor in by hand until the sensor tip just touches the highest point of a gear tooth. From that contact point, back the sensor out counterclockwise by ½ to ¾ of a turn (typically 0.5 mm to 0.8 mm air gap). This spacing is critical for proper signal strength.
5. Secure & Reconnect
While holding the sensor body steady to maintain the set position, tighten the jam nut firmly. Reconnect the wiring harness, ensuring the connector clicks into place and the seal is seated against moisture.
6. Functional Check
Crank or start the engine. Observe the rev counter for steady, bounce-free operation. If the needle jumps or shows no reading, recheck the air gap.
Frequently Asked Questions
| FAQ Topic | Question | Answer |
|---|---|---|
| Engine Compatibility | What Komatsu engines does 716/D2727 fit? | This revolution speed sensor is a direct fit for Komatsu S4D102E, S6D102E, SA6D140, and SA6D95L diesel engines. It may also fit other Komatsu 102 and 140 series engine variants. Always verify the part number on your old sensor before ordering. |
| Part Number Formats | Are 716/D2727, 716-D2727, and 716D2727 the same? | Yes. These three formats all refer to the identical Komatsu OEM revolution sensor. The differences in notation (slash, dash, or compact) are simply variations in how the part number is printed in different parts catalogs or regional systems. COGENG CG-716-D2727 covers all three formats. |
| Sensor Function | What does this revolution sensor do? | This sensor is mounted on the flywheel housing and detects the passing teeth of the ring gear. It generates an AC voltage pulse signal whose frequency is directly proportional to engine RPM. This signal is used by the engine controller for fuel injection timing and by the instrument panel for the tachometer display. |
| Sensor Type | Is this a passive or active sensor? | This is typically a passive inductive (magnetic pickup) sensor. It generates its own AC voltage signal when ferrous gear teeth pass through its magnetic field. No external power supply is required for the sensing function. |
| Air Gap Setting | How critical is the correct air gap? | Extremely critical. If the gap is too large, the signal voltage will be too weak at low RPM, causing erratic or no tachometer reading. If too small, the sensor tip may contact the ring gear teeth, causing physical damage to both the sensor and the gear. Always set the gap to OEM specification. |
| Direct Replacement | Is the COGENG sensor plug-and-play? | Yes. The CG-716-D2727 is manufactured to exact OEM electrical, mechanical, and signal output specifications. The connector is pre-configured with the correct pinout. No wiring modifications or ECU reprogramming is required. |
| Material & Quality | What materials are used in this sensor? | The sensor body is constructed from high-strength iron/steel for durability in the harsh engine environment. The sealing element is oil and high-temperature resistant rubber (Viton/Nitrile). COGENG is an ISO9001 certified manufacturer. |
| Troubleshooting | What if the tachometer is erratic or dead after installation? | Systematically check: 1) Harness connector is fully seated and clicked into place. 2) Correct air gap between sensor tip and ring gear teeth. 3) No bent, corroded, or pushed-back pins in the connector. 4) Wiring harness continuity (both wires) between sensor and controller/gauge. 5) Ring gear teeth are clean and undamaged. 6) Sensor is the correct variant for your engine model. |
| Order & Logistics | What are the payment, packaging, and shipping details? | Payment Terms: T/T, Western Union, L/C, MoneyGram, D/A, D/P. MOQ: Acceptable trial order with no minimum quantity. Packing: PP bag inside, carton box outside. Shipping: By air, by sea, or by express (FedEx, UPS, DHL, TNT) from Guangdong, China. Supply Capacity: 500 PCS. |
Q: What Komatsu engines use the 716/D2727 revolution sensor?
A: The COGENG 716/D2727 (also referenced as 716-D2727 or 716D2727) revolution sensor is a direct OEM replacement designed for Komatsu S4D102E, S6D102E, SA6D140, and SA6D95L diesel engine series. This sensor measures engine rotational speed and is critical for engine timing, fuel injection control, and overall engine management. Always verify this part number against your engine's parts manual or the original sensor's identification markings to confirm exact compatibility before ordering.
Q: What are the symptoms of a failing revolution sensor on a Komatsu engine?
A: Common symptoms include engine stalling or failure to start, intermittent engine shutdowns, erratic or incorrect RPM readings on the monitor panel, rough running or misfiring, active diagnostic trouble codes related to the engine speed sensor circuit, the engine entering a derate or limp mode, or loss of throttle response. A faulty revolution sensor can cause significant engine performance issues and should be replaced promptly to avoid potential engine damage.
Q: How does the revolution sensor affect engine operation?
A: The revolution sensor continuously monitors engine rotational speed (RPM) and transmits real-time data to the engine ECU. This critical information is used to control fuel injection timing, fuel delivery quantity, and engine protection functions. Without accurate RPM data, the engine ECU cannot properly manage combustion or protect the engine from overspeed or underspeed conditions.
Q: What material construction is used for this revolution sensor?
A: The COGENG 716/D2727 revolution sensor is constructed with a durable metal body and high-quality rubber components designed to withstand the demanding heat, vibration, and environmental conditions of the engine compartment. The materials are selected to meet or exceed OEM specifications for durability and long service life.
Q: Is this sensor a direct plug-and-play replacement?
A: Yes, the COGENG 716/D2727 revolution sensor is manufactured to exact OEM specifications for thread size, electrical connector type, signal output characteristics, and mounting dimensions. It is a direct plug-and-play replacement requiring no wiring modifications or adapters when installed on compatible Komatsu S4D102E, S6D102E, SA6D140, or SA6D95L engines.
Q: What are the ordering and shipping options?
A: COGENG accepts trial orders with no minimum order quantity requirement. Payment can be made via Western Union, L/C, T/T, MoneyGram, D/A, or D/P. Shipping options include air freight, sea freight, and international express couriers (FedEx, UPS, DHL, TNT, etc.). Products are packaged in a protective PP bag inside a durable carton box for safe transit. COGENG is ISO9001 certified and ships from Guangdong, China.
Q: What is the warranty coverage for this revolution sensor?
A: COGENG provides a standard 12-month warranty against manufacturing defects from the date of installation. Proof of purchase and installation by a qualified technician are required. Warranty does not cover failure caused by improper installation, wiring damage, physical impact, overtightening, or use on incompatible engines.
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