P0304 - any common reason?

[saar]

Hi,

My 2001 xj, 4L probably thinks I'm bored. I just finished fixing the steering reservoir and now I got P0304 error code.
Any common reason for that? the Jeep has ~115K km, original injectors (from 2001) , original catalytic converter, I had the cylinders head done few months ago.

Any idea?
Thanks,
Saar

[4.3LXJ]

Pretty warm over there right now Saar? Common thing is misfire due to heat soak in the injector when warm causing gas to vaporize and failure in the coil pack

[saar]

Pretty warm over there right now Saar? Common thing is misfire due to heat soak in the injector when warm causing gas to vaporize and failure in the coil pack

Actually, it is winter here now, ~20c :)
What can be done to solve it? why now (after 8 years that I have the jeep)?
Thanks :)

[4.3LXJ]

Actually, it is winter here now, ~20c :)
What can be done to solve it? why now (after 8 years that I have the jeep)?
Thanks :)

Your Jeep is lonely :sign0181:

I would lean towards the coil pack malfunctioning. Try swapping #4 and another to see if it changes to another code. Check the plugs too. If the code doesn't change with the coil, swap plugs. If neither, then it is a heat issue, but doubtful on that one this time of year

[Mudderoy]

Actually, it is winter here now, ~20c :)
What can be done to solve it? why now (after 8 years that I have the jeep)?
Thanks :)

Make sure the wiring loom isn't rubbing on the back of the fuel rail. Pull it up with some tie wraps.

[saar]

Thanks.
4.3LXJ, how do I swap the coils? it is a 2001 model, I have coil bridge, isn't it "one peace"?
Mudderoy, thanks, I will check tomorrow (night time here now).
Saar.

[4.3LXJ]

You might have me there Saar. I have never seen one. All the other motors I have had with multiple coils have replaceable coils.

[saar]

You might have me there Saar. I have never seen one. All the other motors I have had with multiple coils have replaceable coils.

That is the coil "bridge" - I''m using the original, that is only to show the part:
http://www.rockauto.com/catalog/moreinfo.php?pk=444184&cc=1373666

http://www.rockauto.com/getimage/getimage.php?imageurl=http%3A%2F%2Fwww.rockauto.co m%2Finfo%2FSMP%2FUF296_PRIMARY.jpg&imagekey=444184-0&width=450

[4.3LXJ]

What I know about this is that the usual misfire diagnosis was fuel related. But lately there have been a number on several forums that have had bad coil rails. I don't know what they cost, but I would suspect in cold weather this would be the culprit

[saar]

Hi,
I'm not sure if that counts as a cold weather, it is 20c here...
Is it possible that the injectors cause it?

[Mudderoy]

Thanks.
4.3LXJ, how do I swap the coils? it is a 2001 model, I have coil bridge, isn't it "one peace"?
Mudderoy, thanks, I will check tomorrow (night time here now).
Saar.

Mine was driving me nuts. Finally I found this obscure post about the wiring harness rubbing on the back of the fuel rail causing an intermittent short. To my amazement this was the cause of my problem. I can't remember if this was true for the 98+ models though. Simple fix, worth trying.

[4.3LXJ]

Are yo getting a misfire on startup that goes away?

[gary63]

I have a 2000 and had the same problem check you wiring like Mudderoy suggest first then check your fuel pressure if it is to low the fuel will drain back so the first 1 or 2 cyl.will misfire and you will get a trouble code.the other thing is if you run it longenuf
to get it warm and shut it off and only wait 2 to 6 min. or so the fuel in the rail and in the injectors will evaprate and give you a code. fixes wiring just fix it Mudderoy has a post on that.Low fuel pressure replace the pump, the evaporating proble puy a heat reflecter under the rail and wrap the injertors with heat cloth like the stuff you put around the spark plug wires and boots.the coil is the lease or the last thing that coses the code it may be the coil but most of the time it is one of the others.

[saar]

Thank you all.
Where do I buy the "heat reflecter"?
Thanks,
Saar.

[4.3LXJ]

In the states, it is a dealer item that you can get as a factory recall. Not sure about what happens with that in your part of the world. You can also make one out of heat reflective material used in furnaces as such

[saar]

Hi,

A short update:
1. I checked the wires, connectors and heat shield
2. I switched between injector #1 and #4
Now I'll wait to see if it throws the code again...
Thanks,
Saar.

[saar]

Hi,

Honestly, I expected that...
P0304 is back :(
Next:
I'm trying to get the injector's connectors in order to replace them (mine are in a bad shape)
If you know where I can get them, please let me know.
(I couldn't find them in Israel)
Thanks,
Saar.

Edit: I found them at RockAuto, 25$ each - I need 6...
Does the price make sense?
Thanks.

[4.3LXJ]

Here is a bunch, take your pick

jeep injector connectors - Google Search

[saar]

Here is a bunch, take your pick

jeep injector connectors - Google Search (http://www.google.com/search?client=safari&rls=en&q=jeep+injector+connectors&ie=UTF-8&oe=UTF-8#q=jeep+injector+connectors&hl=en&client=safari&tbo=u&rls=en&source=univ&tbm=shop&sa=X&ei=egIhUaf3K4PW9ATduIGYAg&ved=0CFAQsxg&bav=on.2,or.r_gc.r_pw.r_qf.&bvm=bv.42553238,d.eWU&fp=76f74dca1e27311&biw=1179&bih=1320)

Thanks, but I can not open that link (Google's links are "per-location" and they do not allow me see your results - different country...)
Anyway, I decided to start with checking the wiring before replacing the connectors (6 connectors will cost me ~320$ so it worth trying something before... :) )
Thanks, I will keep the post updated,
Saar.