P0304 Frustrations

[HatterMT]

Hey all! I'm new to KJ's, I just retired a 96 XJ at 303k. I bought a 2004 Limited last week with no issues and now I have a misfire on cyl 4. I replaced the spark plug, swapped coils with another cylinder and checked the OHM's on the injector and a couple of others and got 12.8 ohms. Is there something else I should check before I pull the fuel rail and replace the injector? Or is there a way to "clean" it w/o pulling it? It seems like after each time I try something it stops missing till I drive it for a bit. I'm going to go check all my connections again and I might swap the coils back. The misfire has remained on 4. Any thoughts?

Thanks,
Russ

 

[rjkj2005]

Hey all! I'm new to KJ's, I just retired a 96 XJ at 303k. I bought a 2004 Limited last week with no issues and now I have a misfire on cyl 4. I replaced the spark plug, swapped coils with another cylinder and checked the OHM's on the injector and a couple of others and got 12.8 ohms. Is there something else I should check before I pull the fuel rail and replace the injector? Or is there a way to "clean" it w/o pulling it? It seems like after each time I try something it stops missing till I drive it for a bit. I'm going to go check all my connections again and I might swap the coils back. The misfire has remained on 4. Any thoughts?

Thanks,
Russ

Yes. Check compression.

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[HoosierJeeper]

What kind of spark plugs and coil did you use? Use Copper cores only and Mopar coils only.

 

[HatterMT]

What kind of spark plugs and coil did you use? Use Copper cores only and Mopar coils only.

I didn’t replace the coil, just swapped it with another cylinder. I didn’t use the mopar plugs.

 

[HatterMT]

I’m headed to get a compression tester. When I unplug the wires from the coil I can hear it miss. I’m thinking it is a compression issue. Son of a b****. Not even a week old to me.

 

[HoosierJeeper]

What kind of laws do you have for recourse? Obviously they know about it, a compression issue doesn't develop in a week.

 

[HoosierJeeper]

This might be your next step after the compression test.
http://scholarship.law.umt.edu/cgi/viewcontent.cgi?article=1774&context=mlr

It's a little old but might point you in the right direction. I know you probably bought it "as-is" but that doesn't give the seller the right to misrepresent the vehicle, given that it had this condition when you bought it and I'm assuming it wasn't disclosed.

 

[HatterMT]

Thanks for the help. Not sure about the laws yet. It threw the P0304 code the night I bought it, after the "as is" was signed. I told them about it the next day so there is record. It's a reputable dealer so I don't think they intentionally did it. I think it was rushed through the inspection because they wanted to show it to me. I just got the compression tester. I'm headed outside to check it out.

 

[adamkrz]

My 04 KJ had that code when still under warranty - it ended up being a valve problem.

No problems in the past 12 years..

 

[HatterMT]

Well the compression tested good. I put some injector cleaner in about a half tank of gas and the light went off almost immediately and has stayed off. I think I'll replace the injectors next spring if I don't have any more issues. Thanks for the help!

 

[mk_v]

Well the compression tested good. I put some injector cleaner in about a half tank of gas and the light went off almost immediately and has stayed off. I think I'll replace the injectors next spring if I don't have any more issues. Thanks for the help!

What part of montana are you in out of curiosity? I’m in Missoula.


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[HatterMT]

I'm in Helena, Nice to meet you!

 

[Casey.N]

i just recently bought thses injectors https://www.ebay.com/itm/Best-Upgra...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649 12 hole injector upgrading from a 4 hole injector and MAN!! my kj was real happy with those 12 hole over the 4 that i had previously in it, on the first second of driving i noticed a huge gain in throttle response, as for mpg's no difference but man i was stoked on the throttle response of those 12 hole!

 

[HatterMT]

Thanks Casey! I'll look at those, maybe sooner than later! I was planning on doing the 4 hole upgrade to my 96 XJ but never got around to it.

 

[HatterMT]

i just recently bought thses injectors https://www.ebay.com/itm/Best-Upgra...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649 12 hole injector upgrading from a 4 hole injector and MAN!! my kj was real happy with those 12 hole over the 4 that i had previously in it, on the first second of driving i noticed a huge gain in throttle response, as for mpg's no difference but man i was stoked on the throttle response of those 12 hole!

Where can I verify that these will work in my KJ? I don't doubt you I just like to do the leg work to make sure. Do you have the 3.7?

Thanks

 

[Casey.N]

good luck, though there is a slight issue with the mounting of these injectors as they dont allow you to use the metal clip that hold the rail to the injector, the slot for the clip is there but sadly if you decide to utilize it, the injectors sits about half way into the rail and causes it to leak like a B**** what i did is bypassed those clips all together (and i broke two lol) and am allowing the rail to hold the injectors in place, with the 4 bolt holding the rail to the manifold there is no way those injectors are ganna fall out haha. the only issues i had with this install was removing the old injectors. i thought they where bolted in some how but nope you just gatta REALLY pull those suckers out, luckily the new 12 hole injectors came with new Orings, so me destroying the old ones pulling out the injectors quite violently allowed for a clean install, one thing to note, I used a dab of oil on all the Orings to help everything go together smoothly, without doing so youll have leaks all over the place from the injectors not seating correctly!! GOOD LUCK if i can do it you sure as hell can!!

 

[Casey.N]

Where can I verify that these will work in my KJ? I don't doubt you I just like to do the leg work to make sure. Do you have the 3.7?

Thanks

yes sir ive got the 3.7 2002 kj LE 4x4, and if you go the link for the ebay page scroll down a bit and youll see a MASSIVE chart describing what vehicles these fit on. i think they fit on some jk's as well as xj's and most definatley Kj's!
haha i dont doubt why youd want to verify, ha $120. shoot i spent three days decideing before i just said F-it and went for it

 

[HatterMT]

Thanks for the information Casey! I'm looking forward to the upgrade!