How To Test For A Broken Timing Belt (Honda 3.0L)

TEST 1: Check Rotation Of The Camshaft Gear

The top timing covers, on your Honda's 3.0L V-6 engine have a hole, that's designed to aid in diagnosing the timing belt.

This hole is usually plugged to prevent debris and/or water from entering and damaging the timing belt and/or components.

To help you locate this hole, the photo above has an orange arrow pointing to it unplugged.

IMPORTANT: Don't stick any type of object into this hole!

OK, this is what you need to do:

1. 1

   Remove the plug that's covering the hole on the top timing belt cover.
   
   Remember, don't stick anything in there to sense the motion of the cam gear.

2. 2

   Now, have a helper crank the engine as you eyeball the cam gear through the hole.

3. 3

   You'll see one of two things:
   
   1.) You'll see the cam gear turning.
   
   2.) The cam gear is not gonna' be turning.

Let's examine your test result:

CASE 1: The camshaft gear turned. This is a clear indication that the timing belt on your Honda is not broken.

Since your Honda is still not starting, I recommend checking the following:

1. Check fuel pressure. This will test to see if the fuel pump is working.
2. Check for a blown head gasket.
3. Check the crankshaft position sensor.

CASE 2: The camshaft gear DID NOT turn. This indicates that the timing belt is broken and not turning the Cam gear.

You've now confirmed that the timing belt is the cause behind your Honda's cranks but does not start condition.

TEST 2: Check Rotation Of Distributor Rotor (If Equipped)

Not all of the 3.0L V-6 Honda/Acura engines have a distributor, so this test may not apply to you.

For this test to be effective, the battery has to be fully charged, or charged enough to crank your 3.0L Honda Accord.

You are also gonna' need a helper to crank the engine for you. Since you'll be working around a cranking engine, be careful, stay alert and take all necessary safety precautions.

OK, this is what you need to do:

1. 1

   Remove the distributor cap but do not remove the distributor's rotor.

2. 2

   Disconnect the distributor's electrical connectors.
   
   This is super important because the ignition coil must be disabled. The ignition coil must not spark during the test or you run the risk of damaging it, so by disconnecting the distributor's connectors, you effectively disable the ignition coil.

3. 3

   When you're ready, have a helper crank the engine while you observe the distributor's rotor.

4. 4

   You'll see one of two things:
   
   1.) The distributor rotor will turn as the engine cranks in steady circular motion.
   
   2.) The distributor rotor will NOT turn as your helper cranks the engine.

Let's take a look at what your test results mean:

CASE 1: The distributor rotor turned. This is a clear indication that the timing belt on your Honda is not broken.

Now, since your 3.0L equipped Honda/Acura doesn't start, I suggest testing the following:

1. Check fuel pressure. This will test to see if the fuel pump is working.
2. Check for a blown head gasket.
3. Check the crank position sensor.

CASE 2: The distributor rotor DID NOT turn. This indicates that the timing belt is broken and not turning the cam gear, which in turn is not turning the distributor rotor.