Cylinder 8 misfire

[jjandrews33]

Hey guys I'm new to this forum and have a question. I bought my truck a week ago with a misfire and I'm stumped. I have gave it a fresh tuneup plugs wires cap and rotor. That didn't slove anything so I took it to firestone so they could hook up the diagnostic machine. And they told me that the ecm was shot because I wasn't getting a signal from the computer to the #8 injector. So I went yesterday and got a reman computer put it in and still have a misfire. I pulled the plug on the computer and tested for continuity between the connector on the injector and ecm and it tested fine. So now I'm stuck and don't know what to check next.

 

[Merc225hp]

Welcome to RF

Cam sensor under the dizzy cap controls the injectors Mopar part only. But before you go getting one of those or any part, I recommend getting a compression test done on the motor. Start with jug #8 see what you get.

There is also the plenum gasket, there is a sticky thread here on RF done by DD94 you should read through. There is also a TSB on spark plug wire routing TSB 18-48-98

 

[dodge dude94]

^+1 for a compression test first. Misfire on cyl. 8 can most definitely be traced to a cracked head.

 

[jjandrews33]

I've got spark at 8 but the fuel injector isn't responding

 

[Merc225hp]

Swap two injectors test, if it moves to the new spot replace the injector if not then the cam sensor.

Edit; Look inside the male end plug that goes on the injector, make sure both terminals are there I have seen one break off and this makes for a non firing injector

 

[ADudeOnSkis]

+1 for everything those two dudes said. Especially plenum.