I upgraded my factory injectors with bosch 4-hole injectors. (MP202) Everything went fine, they did seem to fit a little bit loose but figured the orings need to expand. Started the jeep and it ran great, a lot smoother and way more throttle response. I flashed the PCM and after i did that i could hear the injectors spraying the fuel if i really listened for it, still ran very smooth though. Next day drove it to town, still ran great but after i parked and shut it off for about an hour i started it and the engine light started flashing and then went to solid. It also wanted to die, idled very rough and then smoothed out as i started driving, drove it to a mechanic shop and had them scan it and said it was a misfire in cylinder 1, they reset the code and told me to go home and check the corisponding spark plug to see if there was fuel on it. I noticed as i was driving back home it seemed like it lost a lot of the throttle response it had before and once i got up to 50 if i left off the gas it would jolt pretty good. Im going to look at the spark plug right now but i dont know what to do if there is fuel on it. Anybody have any advice on what else might cause this misfire?

 

clogged fuel injectors, Spark plugs, Wires, cap, etc...

Max

 

When i pulled the electric connectors off the old injectors a few of them broke but they still stay on. How would i know if the new injector isnt getting that connection?

 

Could always just unplug it and see if it changes

 

They shouldn't feel loose. Usually it's a bit hard, likely the wrong O rings is my thought. (they don't actually "expand") The nature of their fit lets pressure make them seal on side and top, but starting loose is not it.

Btw, my cheap 1ooo piece O ring kit is very handy, but they are all "slim" where some apps call for fatter ones.