How To Find The Bad Or Clogged Fuel Injector
Finding the bad or clogged fuel injector on your 2.6L Isuzu Pickup (2.6L Amigo or 2.6L Rodeo) can leave you scratching your head and wondering where to begin. Fortunately there's a logical starting point since a failed (or clogged) fuel injector will cause its engine cylinder to misfire.
By starting of with a set of specific tests we can, through a process of elimination, find the 'dead' cylinder and figure out what's behind the problem.
I usually recommend starting out with a cylinder balance test but this depends on your level of wrenching experience. A cylinder balance test requires that we unplug one fuel injector at a time (from its connector) and see if the engine RPMs drop or not. If the engine RPMs drop then we know that that cylinder IS NOT misfiring. But if the engine RPMs DO NOT drop (when unplugging that fuel injector), then that cylinder is 'dead' to begin with and is misfiring.
What sucks about doing this type of cylinder balance test on the Isuzu 2.6L engine is that the fuel injector connectors are not within easy reach. So my suggestion to you would be to start by eliminating the ignition system first.
OK, these are the diagnostic steps I would take on the 2.6L Isuzu:
- Find the 'dead' cylinder first. This requires doing a cylinder balance test.
- Check the ignition system for spark.
- It's important to make sure that each cylinder is getting spark with a dedicated spark tester.
- It's important that you check that the spark plug boot and spark plug are NOT soaked (or swimming) in engine oil.
- You should also remove the spark plugs and check them 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 distributor cap, the spark plug wires and the spark plugs as the cause of the engine misfire (miss, rough idle).
- Check engine compression.
- After making sure that the distributor cap, spark plug wires and spark plugs are OK (transmitting spark), you need to check for low engine compression.
- This is one of the most overlooked tests when diagnosing a misfire or rough idle condition. You can find the test here:
- 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).
- Swap the fuel injector with its neighbor on the fuel injector rail.
- I'll swap out the 'dead' cylinder's fuel injector with its neighbor only if:
- The ignition system is not at fault.
- That cylinder's compression value is good (compared to the rest of the cylinders).
- The fuel injector resistance is good.
- I think the fuel injector is clogged.
- I'll swap out the 'dead' cylinder's fuel injector with its neighbor only if:
Finding the bad/clogged fuel injector can be a challenge on your 2.6L Pickup (2.6L Amigo, 2.6L Rodeo) 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 2.6L Isuzu Diagnostic Tutorials
You can find a complete list of 2.6L Isuzu tutorials in this index: Isuzu 2.6L Index Of Articles.
Here's a small sample of the tutorials you'll find in the index:
- 2.6L Isuzu MAF Sensor Test Amigo, Pick Up, Rodeo (1993-96).
- Blown Head Gasket Test Amigo, Pick Up, Rodeo (1993-96 Isuzu 2.6L).
- How To Test The Isuzu Manifold Absolute Pressure (MAP) Sensor.
- Engine Compression Test (2.6L Isuzu) Amigo, Pick Up, Rodeo (1993-96).
If this info saved the day, buy me a beer!
