How To Test For A Broken Timing Belt (1998-2007 3.0L V6 Honda Accord)

A broken timing belt will cause your 3.0L V6 Honda (or Acura) to crank but not start. In this tutorial I'm gonna' show you two ways to test your Honda for a broken timing belt.

The first test works on both distributor and coil-on-plug (COP) equipped Accords. The second test is specific to Accords with a distributor-driven ignition system.

Both tests are laid out step by step so you can quickly confirm whether the timing belt is busted and behind your Accord's no-start problem.

You can find this tutorial in Spanish here: Verificando Si Está Rota La Correa De Distribución (3.0L Honda Accord y Odyssey) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the following vehicles:

• 3.0L V6 Honda Accord: 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007.
• 3.0L V6 Acura CL: 1997, 1998, 1999.

Symptoms Of A Broken Timing Belt

The most obvious symptom that the timing belt broke, on your 3.0L V-6 equipped Honda Accord, is that the engine won't start. It'll crank, but no-start.

If the engine is running, like when you're driving, and the timing belt breaks, the engine is suddenly gonna' stop and it's not going to restart.

Here are a couple other symptoms:

1. In distributor equipped ignition systems, you won't see any spark created or delivered to the spark plugs, since the distributor rotor will not turn.
2. The fuel injection computer will not pulse (activate) the fuel injectors (if your Honda has the crankshaft position sensors in the distributor).
3. If you were to do an engine compression test, none of the engine cylinders would produce a compression reading on the compression tester.

What Does A Timing Belt Do?

The timing belt serves a very important role in starting your Honda 3.0L V-6 engine and keeping it running. In this section, I'll explain in some detail, but without getting too technical, what the timing belt does.

Namely, the timing belt is the belt that controls the camshafts and keeps the intake valves, exhaust valves and pistons synchronized to allow the combustion process to take place (and to keep them from banging into each other).

In a nutshell, this is what happens when you turn the key and crank the engine:

1. The crankshaft (timing gear) drives the timing belt.
2. The timing belt in turn, drives the camshafts on top of the cylinder heads.
   • Your Honda 3.0L V-6 engine has 2 camshafts, one in each cylinder head.
3. The camshafts and the crankshaft are kept synchronized by the timing belt.
4. As the camshafts turn, they activate the intake and exhaust valves
   • The intake valves let fresh air in (to mix with the fuel that will be injected into the cylinder).
   • The exhaust valves let out the exhaust gases from the combustion of fuel and air.
5. The crankshaft activates the pistons and the combustion process begins. In a nutshell, this is what happens (in one cylinder):
   • The piston draws air into the cylinder, since the camshaft has opened the intake valve.
   • The fuel injector injects fuel into the cylinder.
   • The piston starts to compress the air and the fuel since the camshaft has closed the intake valve.
   • The spark plug sparks and ignites the air/fuel mixture, which pushes the piston downward.
   • The piston pushes out the exhaust, which is the end result of the combustion of the fuel and air, since the camshaft has now opened the exhaust valve.
6. Since this process happens in all six cylinders, thanks to the timing belt, the engine starts and stays running.

The timing belt is the one that keeps the valves and pistons synchronized to allow all of the above to happen.

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.

The following engine no-start troubleshooting guide will help you with your next steps:

• How To Troubleshoot A No Start (1998-2007 3.0L V6 Honda Accord).

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're 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.

The following engine no-start troubleshooting guide will help you with your next steps:

• How To Troubleshoot A No Start (1998-2007 3.0L V6 Honda Accord).

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.

Where To Buy The Timing Belt And Save Money

When replacing the timing belt, it's suggested that you also replace: the water pump, the timing belt hydraulic tensioner, the timing belt tensioner pulley and the idler pulley.

Your local auto parts store sells everything you need but at a much higher cost! I used to buy everything at my local auto parts store, till I found out just how expensive their stuff is.

You can compare prices, by following the link on the left. Once you get to the site, they will make sure if the timing belt kit fits your specific vehicle or not. If it doesn't they'll get you the right parts at the right price!

Check it out for yourself!

More Tutorials And Articles

I've written quite a few 'how to' tutorials for the 3.0L V6 Honda Accord that may be of interest to you. You can find them here:

• 3.0L V6 Honda Accord Index Of Articles.

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

• How To Test Engine Compression (1998-2007 3.0L V6 Honda Accord).
• How To Test A Misfire Condition And Misfire Codes (1998-2007 3.0L V6 Honda Accord).
• How To Test The Coil-On-Plug Ignition Coil (2000-2003 3.0L V6 Honda Accord).
• How To Test The CMP Sensors (1998-2002 3.0L V6 Honda Accord).