There’s a total of four fuel injectors in your 2.0 liter K series i-VTEC engine. The RSX fuel injector is responsible for injecting the right amount of fuel into your engine. Controlled by your Acura RSX engine computer, your injectors are there to provide the right balance of fuel. Over time there may be contaminants or other issues that can clog any one of the four RSX fuel injector units in your Acura.
If your RSX fuel injector becomes clogged, or even fails it will cause an imbalance in your K20 engine. This imbalance or engine misfire can sound as though your engine is running on just three cylinders. When this occurs, you’ll need to test the internal resistance of each RSX fuel injector.
Today I’ll be showing you how to test the RSX fuel injector in a 2003 Acura. This RSX is misfiring badly and sputtering as though it’s running on just 3 cylinders. In order to test your RSX fuel injector, you’ll need a digital multimeter.
Because your RSX K series ECU will constantly strive to achieve a stoichiometric air/fuel ratio, a bad injector is going to make that extremely difficult. This DIY testing guide will show you whether or not your RSX fuel injector is clogged or the internal windings have failed.
When your RSX fuel injector goes bad, there’s going to be several issues that are pretty obvious to notice.
Of course one of the early warning signs is a RSX check engine light. When you see the Acura CEL turned on, this means there’s a stored Diagnostic trouble code in your engine computer.
When this occurs you need a suitable OBDII scan tool to retrieve your RSX check engine code. This scan tool will help you diagnose the trouble code as well as erase the code once you’ve replaced the faulty RSX fuel injector.
Some of the more common RSX trouble codes include, but are not limited to; P0300, P0301, P0302, P0303, or even P0304.
Testing your RSX fuel injector
Because the fuel injectors in your K series engine are located in the front of your Acura, you need to remove the intake manifold cover. This cover is held on by two 10mm nuts and those should be removed before you can uncover the intake manifold itself. This can also apply to any K series engine swap, and let you troubleshoot any idle performance issues.
Once you’ve got the intake manifold cover to your K20 removed, you can see your fuel injector connectors. Depress these and unplug the fuel injectors one at a time. Now you can turn the dial to read OHMS or resistance. You’ll be using the multimeter to measure the resistance of your injectors, which will tell you if they have failed or they are clogged.
When you have the fuel injector unplugged, you can begin testing. Using your multimeter probe the two pins on your RSX fuel injector. Don’t bother with polarity or worrying about which color goes to which pin. Using the RSX fuel injector wiring diagram below, measure both PIN 1 and PIN 2.
When testing start at cylinder #1 which is the passenger side of the engine bay. You will be working your way down to cylinder #4.
This test will show you the resistance of your RSX fuel injector. Once you begin make sure to record the resistance of each one. If you find that one injector reads differently than the next, don’t worry.
Your RSX injectors won’t all report the same fuel injector resistance. There should be a small amount of variation between the injectors themselves. What you are looking for however is a fuel injector that reads far outside of the average resistance. For instance a good RSX fuel injector should read a internal resistance between 5 – 11 OHMS Ω.
When you find one injector that falls outside of this range, it’s a clear sign that one has failed on you. If you are certain that one of the cylinders in your RSX is misfiring and your fuel injectors all check out resistance wise, you’ll need to double check your coil-on-plug ignition.
Luckily for you testing your RSX ignition coils is easy to do with your digital multimeter. However there’s still a small chance that your RSX fuel injector has become clogged. To test this you will need to perform a cylinder balance test.
This is done by starting your engine and allowing it to warm up. Once you have done so, unplug the fuel injectors one at a time, but do not unplug more than one. When you unplug your RSX fuel injector your engine idle will fall and your K20 will struggle to stay on.
If you happen to unplug a RSX fuel injector and the engine does not change much, that’s the clogged injector. Remove your fuel injector and install a new replacement unit to restore your K20 engine operation and get your RSX back on the road.
Have any questions about this Acura RSX fuel injector testing guide? leave us a comment below and let us know!