1986-1989 Honda Accord Manifold Absolute Pressure (MAP) Sensor Replacement Guide
If your fuel-injected Accord is running rough, stalling, or getting poor gas mileage, a failing MAP sensor could be the culprit.
- Confirm failure by checking for ECU flash codes 3 or 5 under the driver's seat.
- For 1986-1989 models, the sensor is located inside a black box on the firewall, not directly on the engine.
- Only use a standard replacement sensor (like Standard Ignition); performance sensors (like Skunk2) will not work on a stock engine.
- The 1990 Accord is a different generation and requires a different part.
Is Your MAP Sensor Failing?
A bad MAP sensor sends incorrect information to your Accord's computer, leading to a range of engine problems. Because these cars pre-date modern OBD-II diagnostics, you'll need to check for symptoms and then confirm with the ECU's built-in trouble codes.
Common Symptoms:
- Poor Fuel Economy: The engine may run too rich, using more gas than necessary.
- Rough Idle: The engine may shake, vibrate, or struggle to maintain a steady RPM at a stop.
- Lack of Power & Hesitation: You might feel a delay when you press the gas pedal or a general sluggishness during acceleration.
- Black Smoke from Exhaust: This is a sign of an overly rich fuel mixture, where unburnt fuel is exiting the engine.
- Check Engine Light: On these Accords, a failing MAP sensor will trigger a trouble code stored in the ECU.
Reading ECU Trouble Codes (1986-1989)
Your Accord has a diagnostic system that flashes codes via an LED on the ECU itself, which is located under the driver's seat. To check for codes, turn the ignition to the 'ON' position (without starting the engine) and count the flashes. A MAP sensor failure typically corresponds to:
- Code 3: Indicates a problem with the MAP sensor's electrical circuit.
- Code 5: Points to a mechanical MAP sensor problem, such as a disconnected or cracked vacuum hose.
Choosing the Right Aftermarket MAP Sensor
For a vehicle of this age, OEM parts are often discontinued or extremely expensive. Aftermarket is the most practical choice, but you must select the correct type of sensor for your stock engine.
Warning: Performance vs. Stock Replacement
You will find brands like Skunk2 Racing that offer MAP sensors for Hondas. These are performance-grade, multi-bar sensors designed for engines with a turbocharger or supercharger. Installing a Skunk2 sensor on a stock 1986-1989 Accord will cause it to run extremely poorly and is not a suitable replacement. It requires a programmable computer and is only for highly modified race cars.
For a standard, non-modified Accord, you need a direct-fit replacement. Brands like Standard Ignition (Standard Motor Products) produce sensors designed to function like the original factory part. This is the correct type of part for a daily driver repair.
Replacement Cost
The price for this part is higher than for newer vehicles due to its unique design and lower production volume. Labor costs are low as the job is straightforward for a mechanic.
| Part Type | Estimated Cost |
|---|---|
| New OEM | $400+ (Often discontinued) |
| New Aftermarket | $285.29 |
| Used OEM | $40 - $80 (Varies, carries risk) |
| Shop Labor | $60 - $120 |
Frequently Asked Questions (FAQ)
Where is the MAP sensor located on a 1986-1989 Accord?
Unlike on many cars, the MAP sensor is not directly on the engine. It is located inside a black plastic "emissions control box" mounted to the firewall in the engine bay. You must open this box to access the sensor, which is connected by a vacuum hose and an electrical plug.
Is this guide valid for my 1990 Accord?
No. The 1990 Honda Accord is the first year of the 4th generation and uses a different MAP sensor with a different part number. This guide and the parts discussed are specific to the 3rd generation, 1986-1989 fuel-injected models.
Can I clean the MAP sensor?
While some sensors can be cleaned, failure in these older MAP sensors is typically electronic. Before replacing, it is wise to check the vacuum hose connected to it for cracks, leaks, or blockages, as this can trigger a Code 5. If the hose is fine, the sensor itself likely needs replacement.
Do I need to reset the computer after replacing the sensor?
Yes. After replacing the MAP sensor, you should clear the ECU's memory. To do this, simply disconnect the battery's negative terminal for at least 10-15 seconds. This will erase the stored trouble codes.
Technical Specifications
OEM Part Numbers: 37830-PH3-003 37830-PK1-003
This guide covers the MAP sensor for 1986-1989 Honda Accord models with PGM-FI (fuel injection). It does not apply to carbureted (DX) models or the 1990 Accord.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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