Troubleshooting an engine no-start can be a real head-scratcher because several different problems can cause the engine to crank but not start. But let me tell you, there is a method to the madness.
An engine needs three basic things to start: spark, fuel, and compression. If even one of these is missing, the engine isn't going to start.
So, in this tutorial, I'm gonna' show you how to test each of these areas in a logical, step-by-step way. It's a simple process of elimination that'll help you narrow down the problem and find out exactly what's keeping your engine from starting.
And best of all, many of these tests can be performed with basic tools. Whether you're troubleshooting the problem yourself or taking the vehicle to a shop, this tutorial will help you understand what's going on and make more informed decisions about which repairs may be necessary.
Contents of this tutorial:
APPLIES TO: This tutorial applies to the following vehicles:
- 2.2L Isuzu Amigo: 1998, 1999, 2000.
- 2.2L Isuzu Rodeo: 1998, 1999, 2000, 2001, 2002, 2003.
Difference Between An Engine No‑Start And No‑Crank:
Before we begin testing, I want to clear up the difference between an engine no-crank condition and an engine no-start condition.
These two problems may sound alike, but they point to completely different areas of the vehicle. Knowing which condition you have will help us begin the diagnosis in the right place.
Engine no-crank (the engine doesn't turn over):
- When you turn the key to the START position, the starter motor doesn't turn the engine.
- The problem may be caused by a weak or dead battery, a faulty starter motor, or a problem in the circuit that supplies power to the starter.
Engine no-start (the engine cranks but doesn't start):
- In this situation, the starter motor turns the engine normally, but the engine doesn't start and run.
- The cause is usually a problem with the ignition system, fuel system, or the engine's internal mechanical condition.
So, if your 2.2L Isuzu Rodeo or Amigo has a no-crank condition, you need to begin by checking the battery, starter motor, and starter circuit.
But if the engine cranks but won't start, your diagnosis needs to focus on the three things the engine needs to run: fuel, spark, and compression.
Engine No‑Start Troubleshooting Basics
The key to finding out why your 2.2L Isuzu Rodeo or Amigo won't start is understanding the three basic things the engine needs to run. These are:
- Air and compression: The pistons and valves must draw air into the cylinders and compress the air-fuel mixture tightly enough for combustion to take place.
- Fuel: The fuel injectors must spray the proper amount of gasoline into the cylinders. The electric fuel pump inside the fuel tank supplies the fuel pressure needed by the injectors.
- Spark: The ignition system, including the ignition coil pack, ignition control module, spark plug wires, and spark plugs, must produce and deliver spark to all four cylinders.
If one of these basic requirements is completely missing from all four cylinders, the engine isn't going to start, no matter how long you crank it.
Once you understand this, diagnosing the problem becomes much more straightforward. We now know that we need to:
- Check for spark at all four cylinders.
- Verify that the fuel pump is producing the correct fuel pressure.
- And if spark and fuel are present, perform compression tests to find out whether an internal mechanical problem is preventing the engine from compressing the air-fuel mixture.
How To Troubleshoot An Engine No‑Start Step‑By‑Step
By this point, you understand that a no-start problem on your 2.2L Isuzu Rodeo or Amigo is usually caused by one of three things: a lack of spark, a lack of fuel, or an engine compression problem.
Now we're gonna' put that information to work. By following a logical testing sequence, you'll be able to narrow down the problem and pinpoint what's keeping your engine from starting.
The diagnostic strategy below applies to the 2.2L engine's waste-spark ignition system, which uses a coil pack and an integrated ignition control module instead of a conventional distributor.
Whether you're new to diagnosing engine no-start problems or you've been working on vehicles for years, I've organized the procedure into simple steps. I'll explain what to check, what the test results mean, and provide links to the individual tutorials that can help you complete each test.
STEP 1: Check for spark
- This step involves testing all four spark plug wires for spark with a spark tester. Any standard spark tester will work. The important thing is to use a spark tester instead of relying on improvised methods that can give you misleading results.
- In my experience, a failed ignition system component is one of the most common causes of an engine no-start problem.
- The ignition system components that can prevent spark from reaching the spark plugs include:
- Ignition coil pack and integrated ignition control module.
- Crankshaft position (CKP) sensor.
- Camshaft position (CMP) sensor.
- Worn or fuel-fouled spark plugs.
- Damaged spark plug wires.
- Coil pack diagnostic tests:
- CKP sensor diagnostic tests:
STEP 2: Check fuel pressure
- If spark is present at all four cylinders, our next step is to find out whether the engine is receiving fuel.
- You can check for a fuel-related problem in one of two ways:
- Perform a starting-fluid test. This is a quick way to find out whether the engine will run briefly when an alternative fuel source is introduced.
- Connect a fuel pressure gauge to the fuel rail and measure the actual fuel pressure. This is the most accurate method because it tells you whether the fuel pump is producing the required pressure.
- Fuel pump pressure tests:
STEP 3: Check the engine's mechanical condition
- Checking the engine's internal mechanical condition starts with making sure all four cylinders are producing adequate compression.
- Compression testing is one of the most commonly overlooked steps when diagnosing a difficult engine no-start problem.
- We also need to make sure the engine doesn't have a serious internal problem, such as a blown head gasket, that's preventing the cylinders from building compression.
- Engine compression tests:
- Blown head gasket tests:
- Last but not least, we also need to make sure the timing belt hasn't broken or slipped, since a broken t-belt will definitely cause a no-start condition.
It's A Simple Process Of Elimination
As you can see, finding out why your 2.2L Isuzu Rodeo or Amigo won't start comes down to a straightforward process of elimination. The engine needs three basic things to run: spark, fuel, and compression. Once you understand that, you've already solved half the mystery.
Of course, you'll need a few basic tools to perform the tests (nothing too expensive). I've already covered the recommended tools in the individual tutorials linked in the previous section. Many auto parts stores, including AutoZone and O'Reilly Auto Parts, also have loaner-tool programs. You pay a refundable deposit and get your money back when you return the tool.
And even if you decide to have a professional perform the diagnosis, understanding this process will help you speak with your mechanic or automotive technician with greater confidence. You'll have a much better idea of what needs to be tested to get your Isuzu back on the road.
More 2.2L Isuzu Rodeo And Amigo Diagnostic Tutorials
You can find a complete list of 2.2L Isuzu Rodeo and Amigo diagnostic tutorials in this index:
Here's a sample of the diagnostic tutorials you'll find in the index:
- How To Test The Fuel Injectors (1998-2003 2.2L Isuzu Rodeo, Amigo).
- CKP Sensor Circuit Wiring Diagram (1998-2003 2.2L Isuzu Rodeo, Amigo).
- Fuel Injector Circuit Wiring Diagram (1998-1999 2.2L Isuzu Rodeo, Amigo).
- Fuel Injector Circuit Wiring Diagram (2000-2003 2.2L Isuzu Rodeo, Amigo).
If this info saved the day, buy me a beer!
