How To Test The Fuel Injectors (1998-2001 2.0L SOHC Ford Escort, Mercury Tracer)

You can test a fuel injector, right on the car, to see if it's bad (or not). In this tutorial, I'll show you how.

Now, in case you just suspect that you have a bad (or dirty) fuel injector and don't know where to start, I'll also show you a basic diagnostic/troubleshooting strategy that'll help you get to the bottom of the problem.

You can find this tutorial in Spanish here: Cómo Probar los Inyectores De Combustible (Ford 1.9L, 2.0L) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the following vehicles:

• 2.0L SOHC Ford Escort: 1997, 1998, 1999, 2000, 2001, 2002.
• 2.0L SOHC Mercury Tracer: 1997, 1998, 1999.

Symptoms Of A Bad Fuel Injector

The one symptom you can count on, when a fuel injector fails, is the engine idling rough. Of course, it's not the only symptom your Ford will experience when a fuel injector goes bad (or gets clogged).

Here are a few more symptoms you may see when the fuel injector isn't spraying fuel into its respective cylinder:

• Rough idle.
• Lack of power.
• Hesitation when you accelerate your 2.0L Ford Escort (Focus) down the road.
• Since the 2.0L Ford Escort (Focus) is OBD II equipped, you'll see a misfire diagnostic trouble code (DTC):
  • P0300: Random Cylinder Misfire.
  • P0301: Cylinder #1 Misfire.
  • P0302: Cylinder #2 Misfire.
  • P0303: Cylinder #3 Misfire.
  • P0304: Cylinder #4 Misfire.

As you're probably already aware, fuel injectors can fail in one of several ways:

1. The fuel injector's internal winding suffers an open-circuit or short-circuit problem. When this happens, fuel injector stops injecting fuel.
2. The fuel injector becomes clogged and doesn't spray correctly or not enough fuel. In tech terms: It doesn't atomize the fuel correctly.
3. It comes on and does not turn off (due to electrical issues). In other words: it does not pulse ON and OFF but stays on all of the time spraying a tremendous amount of fuel as soon as you turn the ignition key to the ON position.

The focus of this tutorial is to see if the fuel injector's internal coil has failed (and thus causing the fuel injector to stop injecting fuel), but testing for a clogged injector isn't that much more complicated and I'll show you how in the next page.

Where To Buy The Fuel Injector And Save

The following links will help you comparison shop for the fuel injector on your 2.0L Ford Escort/Focus:

Not sure if the above fuel injectors fit your particular Single Over Head Cam (SOHC) or Dual Over Head Cam (DOHC) 2.0L Ford engine? Don't worry, once you click on the links and arrive on the site, they'll make sure it fits! If it doesn't, they'll find you the right one.

Checking The Injector's Internal Resistance

The fuel injectors on your 2.0L Ford Escort (Focus) have an internal coil winding. When a fuel injector fails, it's usually because this coil winding shorts out.

You and I can check the state of this coil winding (to see if it's shorted or not) by doing a simple multimeter resistance test.

NOTE: Don't have a multimeter or need to upgrade yours? Check out my recommendation: Tekpower TP8268 AC/DC Auto/Manual Range Digital Multimeter (Amazon affiliate link).

Alright, here are the steps:

1. 1

   Disconnect the fuel injectors from their harness connectors.
   
   NOTE: The illustration above will help you identify the cylinder # the fuel injector belongs to.

2. 2

   Place your multimeter in Ohms (Ω) mode and:
   
   Measure the resistance of the fuel injector across its two male spade terminals with the multimeter test leads (see the illustration above).

3. 3

   Write down the resistance value that your multimeter records for the specific fuel injector you're testing. The illustration above will help you identify the cylinder # the fuel injector belongs to.

4. 4

   Repeat steps 1 through 3 on the remaining fuel injectors.
   
   NOTE: The 2.0L Ford Escort (Focus) fuel injector factory manual resistance specification is approximately: 11 to 18 Ohms.

Let's find out what your specific multimeter test results mean:

CASE 1: All fuel injector resistances are within specification. This tells you that your Ford Escort (Focus) fuel injectors are OK. Specifically, that none are shorted or open internally.

Here's why: If any one of the fuel injectors were shorted or open internally, the fuel injector would have registered a radically different resistance value on your multimeter. Since the resistance values for a 4 were uniform, this test result tells you that they are not defective.

CASE 2: One of the fuel injectors registered a completely different resistance value. This indicates that the fuel injector is bad. Replace the fuel injector.

How To Find The Bad Or Clogged Fuel Injector

Finding the clogged or bad fuel injector can seem difficult or even impossible. Thankfully, there's a logical process that we can follow to find it.

I've used the following troubleshooting strategy with a lot of success and I think it'll help you too. The most important first step is to identify the 'dead' cylinder first:

1. Find the 'dead' cylinder first.
   • This requires checking for specific misfire codes (P0301, P0302, P0303,P0304) or doing a cylinder balance test.
2. Once the 'dead' cylinder has been identified, the next step is to make sure it's getting spark.
   • You must use a dedicated spark tester to check for spark.
   • It's important that you check that the spark plug boot and spark plug are NOT soaked (or swimming) in engine oil (this is especially true on the 2.0L DOHC engines where the spark plug sits right on top of the cylinder head).
   • You should also remove the spark plug and check it for cracks or carbon tracks (this is SO important).
     • Here's a real life case study on carbon tracks and how they can cause a misfire: Carbon Tracks Are A Common Cause Of Ignition Misfires.
   • The key here is to eliminate the ignition coil, the spark plug wire and the spark plug as the cause of the cylinder's misfire.
     • The following tutorial will show you how to test the spark plug wires and the ignition coil: How To Test The 4 Cylinder Coil Pack (Ford 1.9L, 2.0L).
3. If spark is present, then the next step is checking that that cylinder has good compression.
   • This is one of the most overlooked tests when diagnosing a misfire or rough idle condition. You can find the test here:
     • How To Test Engine Compression (1997-2003 2.0L Ford Escort, Mercury Tracer).
4. Noid light test.
   • If every test above checks out OK, then the next step is to do a fuel injector Noid light test.
   • The Noid light test will help you make sure that the fuel injector is being activated.
   • The following Noid light article/tutorial may help you: How To Use A Noid Light And Where To Buy It (I know that this is not the most in-depth article on the subject, but it should give you an idea of what is involved).

5. Swap the fuel injector with its neighbor on the fuel injector rail.
   • I'll swap out that fuel injector with its neighbor only if:
     1. The ignition system is not at fault.
     2. That cylinder's compression value is good (compared to the rest of the cylinders).
     3. The fuel injector resistance is good.
     4. I think the fuel injector is clogged.
     If the misfire now follows that swap, I now know that fuel injector is clogged (or bad) and needs to be cleaned or replaced.

Finding the bad/clogged fuel injector can be a challenge on your Ford 2.0L Escort (Focus) but it's doable. What will help you save a lot of time, money and frustration is to first find the 'dead' cylinder. Following the above diagnostic strategy has saved my lunch quite a few times and I think it'll help you too!

More 2.0L Ford Escort And Mercury Tracer Diagnostic Tutorials

You can find a complete list of 2.0L Ford Escort (Mercury Tracer) tutorials in these two indexes:

• 2.0L Ford Escort Index Of Articles.

Here's a small sample of the tutorials you'll find in the index:

• How To Test The MAF Sensor (1997-2002 2.0L SOHC Ford Escort, Mercury Tracer).
• How To Test The Throttle Position Sensor (1998-2003 2.0L Ford Escort ZX2).
• Common Causes Of Spark Plug Failure (1997-2003 2.0L Ford Escort, Mercury Tracer).
• How To Test For A Blown Head Gasket (1997-2003 2.0L Ford Escort, Mercury Tracer).