Dear Abby

Let me preface this thread by saying, my old man always said if a new issue arises go back to where ya last had yer dirty mitts. That said... today after dealing with a coolant blowout which turned into an easy fix I decided to do plugs, wires, cap, & rotor. RC12ECC's gapped .035. NAPA others etc. the old plugs were TERRIBLY worn. Gap was .050+. Wires where breaking on removal etc. FWIW I just picked up this XJ a couple weeks ago. It's my second but a few years in between.

The rig was running pretty good, no highway issues but I felt at idle it could have been a bit smoother, also has an exhaust leak that needs fixing. At any rate I swap out the aforementioned and it's now missing badly. Rough idle, sounds horrible when in gear and stopped. Check engine light came on etc.

firing order is verified amd good. I've pulled and swapped each plug and wire. Like 5 times. Timing Appears to be fine.... I spent over four hours, finally had to walk away. I'm at a loss as to what I could have done. Codes thrown via CEL are 12-43-43-55. Does the double misfire code inform a multiple cyl misfire?
wth else could I have done. Also is it possible the issue was there before and the addition of the new components was enough to worsen an already underlying issue?

HELP
Aggrivated in KS

 

Here is a diagram that was posted in a similar thread, it would help if you shared a year and engine. Good luck.

 

96 4.0

the firing order is correct as I mentioned it's not that sadly.

 

Did you pull the new cap and rotor off and reinstall? To make sure they are seated correctly.

 

Pull all your electrical connectors on your injectors. Give them a good cleaning and reinstall.

Had the same exact symptoms after I did cap, rotor, wires and plugs. The wider gap on old plugs could have been making up for poor fuel injector performance.

An easy way to check is start it, let it idle.. Pull one connector off one injector at a time, if the idle gets worse, you know that injector is functioning. If nothing changes with the idle when you pull the connector, then that injector may be the culprit.

My electrical plugs on my injectors were so corroded with crap that I couldn't even get a reading on my multimeter when trying to measure the resistance.

May sound odd but I was getting the same codes, same symptoms, and that wound up being my issue. I was beating my head against the wall checking firing order, testing spark, even tried a new set of wires and plugs.

 

Thanks LACK! This is exactly the kind of responses I am looking for. I'll give this a day in court this evening! FINGERS CROSSED

 

What's the best way to clean those up? Just a brass brush?

 

I used electrical contact cleaner and a small brass brush. You will need a tiny pick of some sort to get the retainers off the injector plugs.

 

Coming in hot with the knowledge!

 

With a 96, you should be able to pull the full PXXXX code, which is more helpful and detailed than the 2 digit "43" code that you pulled.

I recommend getting a scan tool or a code reader, plug it into the OBD connector under the dash and report back the full code that you have. With this full code, it might point more directly at where the root cause may be (one particular cylinder, etc).

And to confirm; you did NOT have a check engine light before the work performed?

 

Correct, I did not have a CE light before the work. My buddy is bringing over his scanner this evening to pull the P code. My gut tells me it is the #5 cyl and possibly a bit on #1... does the double 43 code indicate multiple cyl misfire?

 

Probably not the root of your problem, but I would put in a new in line fuel filter too, you know, for fun.

 

Ran the scanner gave me the same random misfire code P0030 I think it was. Anyway injectors all checked out good. Decided to swap out cap and rotor again for sanity sake. No change BUT I notice quite a bit of side to side playnin the distributor shaft. Maybe 1/8"? Could this be causing a slight random misfire?

 

1/8 inch? really? I defer to TJ and others but that seems way too much.

You can loosen the plug wires on the cap. Start it, then go around and lift wires one at a time to see which one(s) don't change the sound. Me, after finding the "suspects" I'd look at those plugs.

Googling "dynamic compression" might help some.

 

i also have slight play in my distributor shaft, and I do have a very slight stumble in my idle. From what I've read so far is that it's common and means its time for a new distributor.