engine missfiring

[RobG]

just installed 750cc injectors and a fpr and one of the cylenders seem to be miss firing anyone know why?

 

[the_mork]

Have you tried changing plugs and wires? It is probably a coincidence.

If that doesn't fix it let us know what you are tuning with, what base fuel pressure you are using, and any other recent mods.

 

[ndsti]

Are the injectors new or used?

+1 on the above mentioned settings!

 

[dontfeedphils]

Well first try telling us what you use to tune, if you have a larger fuel pump, and what pressure you set the FPR to.

 

[the_mork]

He has a warlbro 255 listed in his profile.

Another quick option is to make sure all of the injectors are actually firing.

 

[Talon64]

Make sure the injectors are sealed properly. I had air getting into mine and no fuel coming out. Take some carb cleaner and spray near injectors. If engine revs up you know your seals are seal properly. Also I assume you took the spark plug wires off to get to the injectors. Make sure you got them in the right order (4123) and make they are tight.

 

[Gregory]

Can you give us a little more information? Is it missfiring at idle, or when you pull? If it's when you pull, what rpm range?

How are you regulating fuel with the larger injectors?

You can missfire from being lean or rich.

 

[xlMcMlx DsM]

Well there's two causes to misfires: Ignition problems, or fuel delivery problems. Start the car and start pulling off spark plugs wires. If the idle doesn't change, you've found the bad cylinder. OR, if the idle doesn't change at all once you've pulled them all, then that means fuel is the cause of your misfire(most likely). Check the plugs, though. Easiest thing to do first.

 

[tumtum411]

It honestly could be your plugs or wires

 

[92_1g]

Well there's two causes to misfires: Ignition problems, or fuel delivery problems. Start the car and start pulling off spark plugs wires. If the idle doesn't change, you've found the bad cylinder. OR, if the idle doesn't change at all once you've pulled them all, then that means fuel is the cause of your misfire(most likely). Check the plugs, though. Easiest thing to do first.

+1 probably the easiest and fastest way to rule out one or the other.

 

[xlMcMlx DsM]

Also, a fuel problem would be affecting all cylinders(unless you just have a bad injector) But like everyone's said, plugs and wires yo.