The mass air flow sensor in your 2.0 liter engine is also known as your Ford Escort MAF Sensor. This unit is responsible for reading information about the air that’s headed into your engine. It then transmits this information to your Ford Escort Powertrain Control Module or PCM.
The PCM determines the amount of air and the barometric pressure as well as other values. Based on this information the computer knows just how much fuel to inject into your 2.0 liter engine. When your Escort MAF Sensor begins to fail your engine will not run correctly and it can cause damage to your engine if left unrepaired.
Today I’ll be showing you how to test your Escort MAF Sensor in a 2002 ZX2. This Escort is equipped with the 2.0 liter engine, and is equipped with a four wire MAF sensor.
If you suspect that your Escort MAF Sensor is going out, you’ll most likely see a few symptoms with your 2.0 liter Ford.
Symptoms of a bad Escort MAF Sensor
When your airflow sensor starts going south, it can cause serious driveability issues. Most of these happen because your Ford computer won’t have an accurate signal or know how much air is entering the engine.
Because of this your 2.0 liter Escort engine can run excessively rich or lean. This messes up your fuel economy and is outside the parameters of closed loop operation.
If your Escort runs rich for a long period of time, it can cause your catalytic converter to fail and spark plugs to foul. If it runs lean for long periods of time it can cause premature damage to your engine. Here’s a few other symptoms of a failed Ford Escort airflow sensor.
- Poor Fuel Economy
- Engine pinging
- Black smoke from tailpipe
- Sluggish acceleration
What you’ll need to test a Ford Escort MAF Sensor
We’ll be testing your Ford Escort MAF Sensor by checking for power and ground first. To do this you’ll need to open your hood and locate your air flow sensor. This is mounted into the air box, and secured by way of a waterproof plug.
This plug will need to be removed so that you can unlock and free the MAF engine harness. You will then be using your digital multimeter to test the Escort MAF sensor connector.
Test your Ford Escort MAF Sensor for Power
You will begin with PIN D, which should be a solid RED wire or the right most wire. This wire represents the 5 volts signal from your Ford PCM. If your Escort MAF Sensor RED wire does not return a power signal, you will need to make sure that your key is inserted and turned to the “ON” position.
Now you will be testing for the ground circuits, which are PIN C and PIN B. PIN C should be a BLACK wire with a WHITE stripe. PIN B should be a LIGHT BLUE wire with a RED or YELLOW stripe.
Once you have confirmed that your mass air flow sensor is getting power and ground signals, you can test the signal.
How to Test for Escort MAF Sensor Signal
The signal wire is PIN A which is the left most wire coming out of the MAF housing. This wire should be a BLUE wire with a RED stripe. To perform this test you will need to reinsert the MAF connector, and turn on the engine.
Make sure to keep your hands, clothing and tools free from the engine and all moving parts. This includes the engine, pulleys, belts and especially the cooling fans. You can pierce the left most wire to test the MAF signal.
Turn on the engine and at idle, you should see between .8-1.1 volts of DC power. Now you can manually deflect the throttle body open or have a friend press on the gas pedal and raise the engine RPM to 1500.
At this engine speed your Escort MAF Sensor signal should be between 1.2 and 1.4 volts DC. Now you should raise the engine speed to 1800 RPM, which should raise the voltage to 1.8 volts DC.
The voltage in your Escort might not be exactly the same but the signal should be within this range. You should also see no spikes or dips in the MAF voltage. If the Escort MAF sensor is receiving power and ground, but the signal seems intermittent or poor replace it. Replacement mass air flow sensors should always be new, like this unit in our online store.
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