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01 misfires on startup?

nochance9

nochance9

NAXJA Forum User
Location
ogden ut
I had this problem a few months ago and thought it was the plugs, so i replaced them and it went away up until a couple weeks ago. So i replaced the plugs with some E3's. But it's still throwing misfire codes. I don't know what else it could be. Has anyone else had experience with this? It runs strong if your foot is in it and i haven't noticed any performance losses.

Any ideas would be great!
 
X2 I recall seeing someone else with a similar issue with the E3 plugs. Try running some injector cleaner thru it and cleaning the throttle body.
 
Loose the circus plugs, install NGKs as specified for the 00-01 (a**uming 4.0).

Post up the codes you are getting.

Do as Winterbeater says and check the camshaft sensor alignment.
 
How hot is it where you live?

You might be having the heat soak issue as well depending on your climate.

When was the last time you had this issue? Does it occur only on "warm-starts"?
 
veedubshafer said:
Well, take the E3's out and put some champion coppers in it. Then post back.
Click to expand...

It had champions in it when we swapped the plugs the first time and they defiantly were problematic. We replaced them with Bosh platinum plugs and had no problems for like four months. Then we put the E3's in a week or so ago with no improvement. I don't think it's the plugs this time.

wheeling365 said:
Try running some injector cleaner thru it and cleaning the throttle body.
Click to expand...

Running some through the tank right now, did it the same time as the E3's.

winterbeater said:
Search on how to synch the camshaft sensor to the crankshaft sensor with a toothpick. This has helped many misfire situations.
Click to expand...

Will do. Thanks.

CherBear said:
How hot is it where you live?

You might be having the heat soak issue as well depending on your climate.

When was the last time you had this issue? Does it occur only on "warm-starts"?
Click to expand...

Seems to be worse on cold starts. It happened in early winter last time and right now its 60's. Not very hot here.... Yet.

The codes are:

P0300- random cylinder misfire
P0303- cylinder #3 misfire
P0304 or P0306- (i can't remember) -cylinder #4 (or #6) misfire

If it's misfiring on cylinders #3 & #4 do you think i might have a bad coil pack for those cylinders?
 
you seem to have a penchant for fancy plugs.

As said, put the NGKs in it as specified by Chryco--they choose them for a reason (driveability issues).

You could have cracked coil packs or heat soak. There is a TSB for heat soak for 99-01 XJs (99-04 4.0s), but until the plugs are right you will just be chasing your tail looking for other problems that may exist.
 
joe_peters said:
you seem to have a penchant for fancy plugs.

As said, put the NGKs in it as specified by Chryco--they choose them for a reason (driveability issues).

You could have cracked coil packs or heat soak. There is a TSB for heat soak for 99-01 XJs (99-04 4.0s), but until the plugs are right you will just be chasing your tail looking for other problems that may exist.
Click to expand...

Ugh, i just don't want to replace my plugs again. :tear: But fine.

My last final for this semester is tomorrow morning and i'll get to checking the crank and cam sensor thing, seafoam, and the NGK's.

NGK's over Champion's for sure then?

Why don't the E3's work? I mean they're supposed to be the best plug on the market and i've used them in all my vehicles without any problems thus far. Not to mention the 5 year warranty is really nice too.

Also about the heat soak. First off i'm not sure what that is.... Second, it was much hotter than this on my last Moab trip a few weeks back and it didn't give us any problems then, so i'm not sure why it would now.

winterbeater said:
While you have the plugs out, check compression too. The oo's and o1's crack the heads a lot.

3 and 4 do seem to use the same 1/3 of the coil rail, so that is a possibility too.
Click to expand...

I knew about the cracked heads issue when i bought it and i've been keeping a close eye on it while i gather the info and money to build a head to replace the good old 0331.


Thanks for all the help guys, even if it's not exactly what i want to hear...
 
Yeah, NGKs for sure on the 00-01 4.0 engines.

Heat soak is a culmination of a number of design changes that started with the elimination of the fuel return line and pressure regulator from the fuel rail. It is fuel boiling away in the number 3 injector. Once you get the plugs changed (NGKs, did I mention that?) if you have the problem of poor idle/rough running for the first couple minutes of a hot restart a quick and dirty test is to get the engine hot, park and shut down, then open the hood and leave it cool down for 30 minutes. If the problem is gone (or greatly reduced), then congratulations you have heat soak.
 
There was a post very similar to this one about a week ago. E3's causing misfire codes. I haven't had a close look at an xj coil rail but I suspect they're like kastein said, 3 pairs of coils. If that's the case only half of the plugs fire electrode to ground. The other half fire ground to electrode. I suspect those fancy looking +10hp plugs don't like that much due to the weird ground shape.

While you're in there don't forget to clean the grit off your Tornado that the K&N let through. :)
 
Okay, so i did a bit of research on HERE and HERE and i've made a list of possibilities...

1. Plugs
2. Heat soak of #3 injector (seems likely due to misfire code for #3 cylinder)
3. Crank and cam sensors out of calibration
4. Carbon build up in TB and intake
5. Low fuel pressure due to:
-Bad pump
-Check valve
-Leakey injectors
6. Cracked #3-4 coil pack

I just realized you two posted while i was writing this up haha just so you know...

Anything else i should add to the list of possible problems?
 
JJacobs said:
There was a post very similar to this one about a week ago. E3's causing misfire codes. I haven't had a close look at an xj coil rail but I suspect they're like kastein said, 3 pairs of coils. If that's the case only half of the plugs fire electrode to ground. The other half fire ground to electrode. I suspect those fancy looking +10hp plugs don't like that much due to the weird ground shape.

While you're in there don't forget to clean the grit off your Tornado that the K&N let through. :)
Click to expand...

I don't have a Tornado :p

But i do have a k&n... Actually the PO bought it so.... THERE!

And i was never expecting 10 hp or anything, just thought they were nice..

joe_peters said:
Yeah, NGKs for sure on the 00-01 4.0 engines.

Heat soak is a culmination of a number of design changes that started with the elimination of the fuel return line and pressure regulator from the fuel rail. It is fuel boiling away in the number 3 injector. Once you get the plugs changed (NGKs, did I mention that?) if you have the problem of poor idle/rough running for the first couple minutes of a hot restart a quick and dirty test is to get the engine hot, park and shut down, then open the hood and leave it cool down for 30 minutes. If the problem is gone (or greatly reduced), then congratulations you have heat soak.
Click to expand...

I'll try that, the biggest problem is my mom drives it and i don't. So my source of information is not very.... uh.... detailed shall we say? So this Friday she has off work i'll commandeer it for some tests.
 
Last edited:
Hey, so i'm looking into the toothpick aligning stuff. Found THIS which is a good writeup and i'm ready to try it out. Only one thing.... Where is this sensor? I take it it's not on the bell housing like my 89, is it in the hole where the distributor used to go? Just want to get all my facts ready so i can tear into this thing and get it done quickly but i don't have access to the Jeep at the time...
Thanks
 
nochance9 said:
Hey, so i'm looking into the toothpick aligning stuff. Found THIS which is a good writeup and i'm ready to try it out. Only one thing.... Where is this sensor? I take it it's not on the bell housing like my 89, is it in the hole where the distributor used to go? Just want to get all my facts ready so i can tear into this thing and get it done quickly but i don't have access to the Jeep at the time...
Thanks
Click to expand...

Nevermind, i checked it out and it is.
 
JJacobs said:
I haven't had a close look at an xj coil rail but I suspect they're like kastein said, 3 pairs of coils. If that's the case only half of the plugs fire electrode to ground. The other half fire ground to electrode. :)
Click to expand...

Just curious. How does one go to ground and the other to the electrode? Usually you have good explanations and I want to learn more.:confused:
 
Talyn said:
If it is doing it when cold there is a TSB that address a PCM programming issue by doing a re flash.
Click to expand...

It does do it when it's cold... I'm going to do the toothpick sensor thing first then maybe look into that. Do you have any more info on that?
 
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