This tutorial will help you to test the mass airflow sensor (MAF) sensor using a multimeter.
You'll be able to easily find out if the MAF sensor is bad or not with 3 simple tests.
Each test is explained in a step-by-step manner and in plain English.
If you need to just clean the MAF sensor, you can find this article here: How To Clean The MAF Sensor (GM 3.3L 3.8L).
NOTE: This is an ON CAR test -no need to remove the MAF sensor from its place to test it.
Contents of this tutorial:
- Common Symptoms Of A Bad MAF Sensor.
- What Tools Do I Need?
- Circuit Descriptions Of The MAF Sensor Connector.
- Where To Buy The MAF Sensor And Save.
- How Does The MAF Sensor Work?
- TEST 1: Making Sure The MAF Sensor Is Getting 12 Volts.
- TEST 2: Making Sure The MAF Sensor Is Getting Ground.
- TEST 3: Testing The MAF Signal With A Multimeter.
- More 3.3L V6 Buick, Oldsmobile Tutorials.
You can find this tutorial in Spanish here: Cómo Probar El Sensor MAF (1989-1993 3.3L V6 Buick, Oldsmobile) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles:
- 3.3L V6 Buick Century: 1989, 1990, 1991, 1992, 1993.
- 3.3L V6 Buick Skylark: 1989, 1990, 1991, 1992, 1993.
- 3.3L V6 Oldsmobile Achieva: 1992, 1993.
- 3.3L V6 Oldsmobile Calais: 1989, 1990, 1991.
- 3.3L V6 Oldsmobile Cutlass Ciera: 1989, 1990, 1991, 1992, 1993.
Other MAF sensor test tutorials (at: easyautodiagnostics.com):
- How To Test The GM MAF Sensor (3.1L, 3.4L, 4.3L, 5.0L And 5.7L)
- How To Test The MAF Sensor (GM 3.8L V6 1996-2005)
- How To Test The MAF Sensor (GM 4.8L, 5.3L, 6.0L, 8.1L)
- How To Test The GM MAF Sensor Express And Savana Van (2003-2008)
Common Symptoms Of A Bad MAF Sensor
Here is a basic list of the symptoms you'll see when the MAF sensor fails on your 3.3L V6 equipped Buick or Oldsmobile:
- Check engine light illuminated on your instrument cluster.
- MAF sensor trouble codes stored in your vehicle's fuel injection computer's memory.
- Lack of power when accelerating the engine/vehicle.
- Black smoke coming out of the tailpipe.
- Bad gas mileage.
- Engine idles rough.
- Engine starts but immediately stalls.
- Extended engine cranking. In other words, you've got to crank the engine a long time for it start.
What Tools Do I Need?
You'll need a few basic/simple tools to be able to diagnose the MAF sensor on your 3.3L V6 Buick or Oldsmobile.
- A multimeter that can read Hertz frequency. If you don't have one and would like to buy one, check out my recommendations here: Buying A Digital Multimeter For Automotive Diagnostic Testing (at: easyautodiagnostics.com).
- A wire piercing probe or a back probe to be able to access the signal within the MAF sensor's output signal wire. To see what this tool looks like, click here: Wire Piercing Probe.
- Although not an absolute must, a code reader or a scan tool to be able to extract any codes registered in the fuel injection computer's memory.
As you can see, there's nothing in the list above that will break the bank!
Circuit Descriptions Of The MAF Sensor Connector
As you're probably already aware, there are three wires sticking out of the MAF sensors connector.
You'll notice that the photos (in the image viewer) have the MAF connectors lettered A thru' C (if you look closely at the MAF sensor connector, you'll see these letters on it too). I'll be using these letters for the circuit descriptions.
Here's a basic description of the job each wire does:
|A||Yellow (YEL)||MAF Signal|
|B||Black with white stripe (BLK/WHT) or Black (BLK)||Ground|
|C||Pink with black stripe (PNK/BLK) or Pink (PNK)||12 Volts DC|
To test the MAF signal circuit I recommend that you use a wire-piercing probe or a back probe. You can see what this tool looks like here: Wire Piercing Probe.
IMPORTANT: All of the tests are ON CAR TESTS, do not remove the mass air flow sensor from the vehicle or from its plumbing.
Where To Buy The MAF Sensor And Save
The following links will help you to comparison shop for a known automotive name-brand MAF sensor (no knock-offs) for your 3.3L V6 Buick or Oldsmobile vehicle:
How Does The MAF Sensor Work?
In a nutshell, the MAF sensor's job is to measure the amount of air that the engine is breathing.
The MAF sensor has two hot wires. As air passes over these two hot wires, they cool down. The amount that the hot wires cool down correlates to the amount of air entering the engine.
The MAF sensor then sends this air flow measurement to the fuel injection computer as a high-frequency digital signal.
The cool thing is, that you and I can measure this signal with a digital multimeter that can read Hertz frequency (or with an oscilloscope).
As more air enters the engine, and passes over the hot wires, the greater the MAF Hertz signal is going to be.
If the MAF sensor is working correctly, it's Hertz signal will increase/decrease as you accelerate/decelerate the engine.
If the MAF sensor is bad, then it's Hertz signal will stay stuck in one value as you accelerate/decelerate the engine. It's as simple as that!