In this this tutorial, I'll show you one of the ways to test for a BAD fuel injector by doing a fuel injector resistance test.
Since the 4.7L V8 engine is equipped with 8 fuel injectors, I'll also show you a specific diagnostic strategy you can use to find the or BAD fuel injectors.
Here are the contents of this article at a quick glance:
The three most common ways that a fuel injector fails are:
No matter what the root cause, a BAD fuel injector will cause the engine to idle rough and miss when you accelerate it down the road.
What throws a ‘wrench into the works’... is that the PCM won't always set a specific fuel injector trouble code. But if it does, you'll see one of the following:
From personal experience... I can tell you that around 90% of the time, when you do have a BAD fuel injector, you'll see a misfire trouble code:
And well... the other symptoms your vehicle may experience are:
To do a fuel injector resistance test, you don't need a whole lot of stuff, since the most important tool you'll need is a multimeter (which can either be an analog multimeter or a digital multimeter).
Here's a basic list of tools you'll need:
There's a good chance that you already have one (or several) specific fuel injector you want to test or you don't know where to start...
If you want to test just one fuel injector or several, this will be your starting point. If you don't know where to start, I suggest you do a cylinder balance test to find out which cylinder is the one that's ‘dead’ and could possibly have a BAD fuel injector.
If possible, do the fuel injector resistance test with a slightly warmed up. If your Dodge or Jeep SUV or pickup has been running for a while and it's hot, let it cool down for about an hour. If it's completely cold... crank up the engine and let it warm up for about 20 minutes.
Although having the engine warmed up helps to get a more accurate snapshot of the condition of the fuel injectors, it's not that critical...
...So, if you have already removed the fuel injector or fuel injectors, or the vehicle Cranks but Does Not Start, etc., you don't have to install the fuel injectors and start the engine to warm her up. You can test them cold (and off of the vehicle).
Alright, here are the steps:
Unplug the fuel injector from its electrical connector.
Place your multimeter Ohms mode.
Continued in the next page.
“I never made a mistake in my life. I thought I did once, but I was wrong.”
Charles M. Schulz