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Checking for bad injectors

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I common cause to a truck that is missing is a bad injector. Tracking a bad injector is very simple. There are a few precautions you need to take first. The injectors do spray at high pressure. It tends to atomize instead of shoot at you but it still should not be taken for granted.

A bad injector may have one of these problems:

[*]Low pop pressure

[*]Bad spray pattern

[*]Clogged nozzle

[*]Improper assembly (if you cleaned them and put them back together)

There are a few people wondering what a miss even sounds like so this video should clear that up. By cracking each injector one at a time, the engine should miss worse since 2 injectors should now be not working. When you get to the injector that makes no difference when you crack the line, that is the bad injector (since it should have made the engine miss more). It is always good practice to check them all as there may be 2 bad injectors, or more.

One thing to remember is that cracking the lines still pops the injectors, but not much. I cracked all of my injectors but one and it ran rough, but ran. When I took the nuts on the 5 injectors completely off (rather than having them just cracked) and left just one injector tight, it would not run. Cracking them makes the injectors not flow as much fuel as needed to run the engine and can be heard as a slight miss, taking the nut completely off will create a more solid miss since that injector is not firing at all. It is also safer to take the nut completely off as the fuel will mainly just drain down the side rather than shoot out of the top of the nut like it does when you crack it. The only problem with that is that you need to turn the engine off to completely loosen the nut, otherwise it is pretty dangerous.

The video shows me cracking a line to check if the injector is working, if it starts missing when you loosen the nut, then you know its doing it's job. The rest of the video is after taking the nuts of 4 injectors completely off and then tightening them to show how it changes.


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