93 jeep xj misfiring with codes 11 12 27 34

jeep
cherokee

#1

My inline 6 engine softly stutters and misfires while driving and has the check engine light on whenever this happens. It’s becoming more frequent now - 20% of the time I’m driving I’d say. The codes are 11, 12, 27, 34. I’ve looked up the meanings of the codes and I’m leaning towards its bad fuel injectors or a bad connector leading to the fuel rail. I have lots of bad wiring on my 93 Cherokee haha. I’ve fixed so far: a bad head light connector, and an exposed wire that connects to my distributor - it would swing and touch my engine block causing the engine to die. Haha. But now I am struggling on how to fix my small stuttering engine problem.
So the problem only occurs after I make a strong left hand turn such as a 90 degree or a uturn so that means a connection is being pulled to the right. It doesn’t have an issue turning to the right though. I don’t have sway bars on my 6" lift so there’s a reasonable amount of body roll to pull on the wires etc. When I open the hood with the engine running smoothly I can touch and wiggle the front fuel injectors and sometimes I hear it softly misfire or sputter.
So I’m hoping a 1993 jeep Cherokee master owner can tell me how to fix this. What connectors lead up to the fuel rail? GOOGLE sure doesn’t help me. I’ll type in ‘1993 Cherokee diagram’ and the first result will be like a 95 yj diagram or something idiotic or a 98 grand Cherokee limited diagram. Google is horrible so that’s why I’m hoping someone can help me. I gave a straight forward description. All I need is a ‘1993 XJ’ fuel rail diagram or some advice that I don’t know about yet. Thanks! :slight_smile:


#2

Make sure the fuel injection rail and all connectors are nicely tight. Gently wiggling the rail or injectors should not cause misfires.


#4

Thanks for trying but I kinda already understood the basics. Of course eveything should be tight fitting and it is but what are all the pin point problem areas that it could be? My fuel regulator possibly?

(Edited because of typos, ignore this line sorry)


#5

Maybe not the fuel pressure regulator because my problem only occurs after a motion like turning to the left. So what connectors are affected by a rightward swing when turning to the left. My jeep always starts 100% of the time.


#6

If you can “jiggle” injectors those injectors can be leaking air around them.


#7

A broken motor mount allowing the engine to shift and pulling on the wiring.


#8

No harm asking, but if you can’t find the necessary info using Google or here, have you considered purchasing a repair manual? Or purchasing an All-Data subscription for your vehicle, very low cost for that.

If interested in a wild guess, I can’t speak to your Jeep , but my Corolla is a similar OBD I vintage. If I had that problem I’d bump the revs a little while watching it, see if it is twisting an unusual amount or differently in one direction than the other. If so, I’d correct that problem, likely a faulty mount somewhere. Beyond that I’d use whatever test equipment was necessary – in my case I’d likely use an o’scope - – to make sure all the fuel injectors were being pulsed the same. And I’d do a fuel rail pressure test, set it up so I could watch it while driving in a situation when this happens.