Fuel injectors rarely go bad but when they do, they can give you serious headaches. Don’t worry however, it’s not as bad as you think. A bad fuel injector isn’t that serious and it’s almost never terminal, it’s just a real issue to solve if you don’t know what you’re doing. Thankfully there are a lot of articles online, and this is one of them. Specifically, this is an article regarding Jeeps (1986-2010).
One great thing about Jeeps is that they’re extremely easy to work on. Because the engine bay is large and the actual engine isn’t crammed into the bay, you have a lot of room to carry out every procedure. The fuel injectors are very accessible, making it less of a challenge for a novice.
Diagnosing a bad fuel injector is relatively simple. For starters, the most obvious tell-tale sign is a misfire, either in one or more cylinders. When checking for a faulty fuel injector, get the engine to operating temperatures if you can. If it won’t start, you don’t have to worry about achieving operating temperatures.
The easiest way to check fuel injectors is by using a multimeter. Disconnect the fuel injectors and attach the test leads to the male spade terminals. Measure the resistance (Ohms) of the injector. Ideally, you want to find out what the resistance should be from a manual (often it’s between 13.3 and 15.7 for V6 Jeeps), but if you can’t figure that out, there’s another way. Simply measure all of the fuel injectors. That way you’re getting a pretty decent estimate as to what the average reading should be and you can track down and isolate a single fuel injector should it deviate from the norm.
If the resistance is roughly the same for all fuel injectors (within the allowed tolerance), the problem’s not in the fuel injector. If one fuel injector reading deviates too much, you know that it’s faulty and that it needs replacement.
The second method requires a vehicle equipped with OBD II. Later model Jeeps have it, but make sure to check if yours does. The procedure is simple. You attach an OBD reader to the port and it tells you all of the faults (if there are any). In 90% of the cases with a faulty fuel injector it will print a misfire rather than just a code for a bad fuel injector (check to a manual or online guide for specific Jeep codes).
To ensure that fuel injectors last you a long time, always purchase OEM ones or fuel injectors from a reputable manufacturer. The cheaper alternatives may sound tempting, but they will cost you more in the long run. After all, a fuel injector isn’t something which needs replacing that often. It’s better to buy a decent quality one from the get-go, rather than go through a pair of cheaper ones before finally switching over.