P0303 driving me nuts...

I can't get rid of it. The code popped up while i was attempted a hill climb. It has not gone off for about 3 weeks. The jeep's been sitting on jack stands for a week and 1/2 and hasn't been started. I bought a code reader and got the P0303 code and tried to erase it but it stays on. I tried disconnecting the battery and it goes off for a split second and pops right back on. I checked the plug gaps and they are all teh same .035. I swapped plug 3 with 4 and no luck there. What do i do next?

Jeep's not running rough or anything.

muddeprived said:

I can't get rid of it. The code popped up while i was attempted a hill climb. It has not gone off for about 3 weeks. The jeep's been sitting on jack stands for a week and 1/2 and hasn't been started. I bought a code reader and got the P0303 code and tried to erase it but it stays on. I tried disconnecting the battery and it goes off for a split second and pops right back on. I checked the plug gaps and they are all teh same .035. I swapped plug 3 with 4 and no luck there. What do i do next?

Jeep's not running rough or anything.

Click to expand...

Information is helpful when requesting help...

SAE OBD-II DTC P0303 is a cylinder #3 misfire (just to let everyone else know. You can look them up here - http://www.geocities.com/JeepI6Power/obd2.html - I've gathered them from various Jeep FSMs. I also have OBD-I DTCs listed - separate page.)

It would also help to know what year your rig happens to be - since 1996-1999 came with conventional electronic distributor ignition, and 2000-2001 uses "coil rail" ignition (no distributor.) This makes troubleshooting a bit difficult.

However, it isn't always a spark plug proper that can cause a misfire. I'd check for a good connection between the spark plug and spark plug terminal on the HT lead (you should hear an audible "click" when fully seated. Also, visually check the inside of the terminal for corrosion that may be interfering with connection.) This would apply to both conventional distributor and COP/coil rail ignition. And, if you still have a dizzy, pull the #3 wire and check resistance - I think the "nominal" spec is something like 1000 ohms per foot of wire, for "resistance" wires (like we've got.)

Have a "noid light?" They only cost a few bucks, and you can use them to check to make sure the fuel injector is getting a trigger pulse from the ECU. The injector coil proper may also be checked with an ohmmeter - I don't recall the spec, tho.

But, first and foremost, it really helps to give what information you have to hand - and, if you've been working on the problem, chances are you've already looked up the code. I was feeling rather charitable - else I'd have just said "give us more information" instead of looking it up for you. There's really no excuse not to - it's out there (you can find a lot of it on my site, and I'm planning on adding a good deal more as I accumulate it.) Also, giving with year/engine is very important, since it tells us right away what generation of controls are used, and there's got to be someone who knows what the quirks of your year happen to be. Even if you don't know what your DTC indicates offhand, there is no excuse to not be able to give with the basic vehicle information - so you may consider yourself read off for that one (sorry, but that's just the way it are. Basic troubleshooting relies upon gathering information, so give with what you already know. Saves us the trouble of asking...)

5-90 said:

Information is helpful when requesting help...

SAE OBD-II DTC P0303 is a cylinder #3 misfire (just to let everyone else know. You can look them up here - http://www.geocities.com/JeepI6Power/obd2.html - I've gathered them from various Jeep FSMs. I also have OBD-I DTCs listed - separate page.)

It would also help to know what year your rig happens to be - since 1996-1999 came with conventional electronic distributor ignition, and 2000-2001 uses "coil rail" ignition (no distributor.) This makes troubleshooting a bit difficult.

However, it isn't always a spark plug proper that can cause a misfire. I'd check for a good connection between the spark plug and spark plug terminal on the HT lead (you should hear an audible "click" when fully seated. Also, visually check the inside of the terminal for corrosion that may be interfering with connection.) This would apply to both conventional distributor and COP/coil rail ignition. And, if you still have a dizzy, pull the #3 wire and check resistance - I think the "nominal" spec is something like 1000 ohms per foot of wire, for "resistance" wires (like we've got.)

Have a "noid light?" They only cost a few bucks, and you can use them to check to make sure the fuel injector is getting a trigger pulse from the ECU. The injector coil proper may also be checked with an ohmmeter - I don't recall the spec, tho.

But, first and foremost, it really helps to give what information you have to hand - and, if you've been working on the problem, chances are you've already looked up the code. I was feeling rather charitable - else I'd have just said "give us more information" instead of looking it up for you. There's really no excuse not to - it's out there (you can find a lot of it on my site, and I'm planning on adding a good deal more as I accumulate it.) Also, giving with year/engine is very important, since it tells us right away what generation of controls are used, and there's got to be someone who knows what the quirks of your year happen to be. Even if you don't know what your DTC indicates offhand, there is no excuse to not be able to give with the basic vehicle information - so you may consider yourself read off for that one (sorry, but that's just the way it are. Basic troubleshooting relies upon gathering information, so give with what you already know. Saves us the trouble of asking...)

Click to expand...

I apologize. I am having difficulties changing my signature. When i change it and save it doesn't save it. I'll have to speak to the mods about that.

But anyways, it's a 2001 with 84k and 4.0.

I changed the plugs about a week prior to the off road trip where it popped up. The old plugs had larger gaps (Factory 82k old) than the new champion plugs.

I just received an ohmmeter for xmas so i'm gonna have to learn how that works and check some things out. I find this funny cuz i've owned 5 vehicles in the last 12 years and never had a single motor issue with any of them (ford, car, car, car, TJ) and i just bought this xj and bam, check engine light.

muddeprived said:

I apologize. I am having difficulties changing my signature. When i change it and save it doesn't save it. I'll have to speak to the mods about that.

But anyways, it's a 2001 with 84k and 4.0.

I changed the plugs about a week prior to the off road trip where it popped up. The old plugs had larger gaps (Factory 82k old) than the new champion plugs.

I just received an ohmmeter for xmas so i'm gonna have to learn how that works and check some things out. I find this funny cuz i've owned 5 vehicles in the last 12 years and never had a single motor issue with any of them (ford, car, car, car, TJ) and i just bought this xj and bam, check engine light.

Click to expand...

I'll save you the trouble - I'm a mod. I'm also outgoing BoD (since my term is up with the first of the year.)

The reason you can't save a "custom sig" is also the reason you can't U/L a custom avatar - you're a User, not a Supporter or a Member. The difference? Black names (like yours) are here getting information. Green or Red names have paid to help keep the lights on - so they get to do a little bit more.

We had to make this change about six months ago. We were getting buried in traffic, so we created the "third tier" of membership (Supporter,) and gave people an opportunity to pay a bit less - but nonetheless help keep the lights on around here. It's working fairly well.

In case you may have been wondering, it would also explain why you weren't able to post in Non-Tech - which was the biggest drain on our bandwidth.

Was it a popular decision? Not at first - but it settled down after a bit. Has it helped? We seem to think so - and the figures have borne this out. We're slowly accumulating Supporters, we've got a couple dozen or so. Being a Supporter gives you almost full access - you don't get into the Members Area, and you can't participate in Corporate governance (can't run for BoD, can't vote,) but you're still helping, and your increased privileges would reflect that. Care to sign up?

5-90 said:

I'll save you the trouble - I'm a mod. I'm also outgoing BoD (since my term is up with the first of the year.)

The reason you can't save a "custom sig" is also the reason you can't U/L a custom avatar - you're a User, not a Supporter or a Member. The difference? Black names (like yours) are here getting information. Green or Red names have paid to help keep the lights on - so they get to do a little bit more.

We had to make this change about six months ago. We were getting buried in traffic, so we created the "third tier" of membership (Supporter,) and gave people an opportunity to pay a bit less - but nonetheless help keep the lights on around here. It's working fairly well.

In case you may have been wondering, it would also explain why you weren't able to post in Non-Tech - which was the biggest drain on our bandwidth.

Was it a popular decision? Not at first - but it settled down after a bit. Has it helped? We seem to think so - and the figures have borne this out. We're slowly accumulating Supporters, we've got a couple dozen or so. Being a Supporter gives you almost full access - you don't get into the Members Area, and you can't participate in Corporate governance (can't run for BoD, can't vote,) but you're still helping, and your increased privileges would reflect that. Care to sign up?

Click to expand...

Then i better pay up!

I'll submit some $$ after xmas. Right now my wallet's dry

Thanks for letting me know.

Chris

muddeprived said:

Then i better pay up!

I'll submit some $$ after xmas. Right now my wallet's dry

Thanks for letting me know.

Chris

Click to expand...

No worries - that's why we're here!

However, I think you'll find that signing up is worth it - especially with all the experience we've got around here. Membership does seem to pay for itself in reasonably short order...

5-90 said:

No worries - that's why we're here!

However, I think you'll find that signing up is worth it - especially with all the experience we've got around here. Membership does seem to pay for itself in reasonably short order...

Click to expand...

Yes i believe it will. I was a member of jf before and after a while i noticed alot of the peeps on that board are as$es. I didn't pay up for a membership here right away cuz i wanted to see what the folks were like and so far so good. I like this forum better than most.

muddeprived said:

Yes i believe it will. I was a member of jf before and after a while i noticed alot of the peeps on that board are as$es. I didn't pay up for a membership here right away cuz i wanted to see what the folks were like and so far so good. I like this forum better than most.

Click to expand...

Yeah - I check out JF from time to time as well. Sometimes decent stuff, but I'm not impressed on the whole. Oops.

Granted, you'll get arses everywhere, it's just what percentage they make of the whole that makes them tolerable or no...

You might find my recent thread relevant to troubleshooting your PO303 code problem.

http://www.naxja.org/forum/showthread.php?p=243701807#post243701807

http://www.naxja.org/forum/showthrea...ghlight=Taurus

So 5-90, what's up with the tri-nitro-toluene Avitar?

Ecomike said:

So 5-90, what's up with the tri-nitro-toluene Avitar?

Click to expand...

I should have figured you'd pick it out...

No reason - just been under a lot of stress lately, and thought it might be a fun thing to do. It was either that or nitroglycerine. Or dimethyl hydrazine. Or RDX. Or nitrocellulose. Or ...

5-90 said:

I should have figured you'd pick it out...

No reason - just been under a lot of stress lately, and thought it might be a fun thing to do. It was either that or nitroglycerine. Or dimethyl hydrazine. Or RDX. Or nitrocellulose. Or ...

Click to expand...

Nah, you picked the best one. What is amasing is that it is at all stable under any conditions considering its components. Looking at its structure it is no wonder it is shock sensitive. One of the few avitars of yours I understood! LOL.:sunshine:

Ecomike said:

Nah, you picked the best one. What is amasing is that it is at all stable under any conditions considering its components. Looking at its structure it is no wonder it is shock sensitive. One of the few avitars of yours I understood! LOL.:sunshine:

Click to expand...

I like Composition C4 better, but it doesn't have a clearly defined structure (it's RDX with a plastic binder.)

And, the "general stability" of TNT is also why I picked it - generally, I'm quite stable. However, people who have been calling me lately (I've had to spend a lot of time on the phone with the in-laws. I hate phones, and I've not become overly fond of my in-laws of late...) have kept me close to "detonation." Oops...

5-90 said:

I should have figured you'd pick it out...

No reason - just been under a lot of stress lately, and thought it might be a fun thing to do. It was either that or nitroglycerine. Or dimethyl hydrazine. Or RDX. Or nitrocellulose. Or ...

Click to expand...

Nice stuff, but I have little use for them, they tend to catastrophically disasemble themselves not to mention the disturbance they cause many neighboring molecules with their somewhat violent and uncontrollably behavior when they get too excited. I prefer gasoline and diesel, I get a lot more MPGs out them with out damaging my engine.

So what happened to our guest with the P0303 code problem, hope we did not scare him off?

Ecomike said:

Nice stuff, but I have little use for them, they tend to catastrophically disasemble themselves not to mention the disturbance they cause many neighboring molecules with their somewhat violent and uncontrollably behavior when they get too excited. I prefer gasoline and diesel, I get a lot more MPGs out them with out damaging my engine.

So what happened to our guest with the P0303 code problem, hope we did not scare him off?

Click to expand...

Dunno. Hope the advice I'd given him worked. Or, at least, helped him narrow down the problem...

"Catastrophically disassemble themselves." I like that. Kinda like "achieving the doornail commonality" - great way ot obfuscate what really happens, you know?

5-90 said:

"Catastrophically disassemble themselves." I like that. Kinda like "achieving the doornail commonality" - great way ot obfuscate what really happens, you know?

Click to expand...

Thanks, nice comeback, I was just trying to be more precise at the molecular level and a bit ellegant with the description, helps relieve my current bordom while avoid the daytime Christmas shopping crowds and their innate madness.

But I may have missed part of your metaforical reply message, "commonality" (?) the doornail part I sorta got.

Ecomike said:

Thanks, nice comeback, I was just trying to be more precise at the molecular level and a bit ellegant with the description, helps relieve my current bordom while avoid the daytime Christmas shopping crowds and their innate madness.

But I may have missed part of your metaforical reply message, "commonality" (?) the doornail part I sorta got.

Click to expand...

It's not mine per se - it's something I picked up on the GG fanlist. I suppose it refers to the "commonality" of the fate of all meat - sooner or later, we're all going to shove off. At least, that makes sense to me.

Some of us get there quickly, some of us rather later. Some of us just don't get there fast enough (like people working for the City.) However, death isn't strictly "one to a customer" - while it gets around to you sooner or later, some of us get several visits before it finally sticks...

5-90 said:

It's not mine per se - it's something I picked up on the GG fanlist. I suppose it refers to the "commonality" of the fate of all meat - sooner or later, we're all going to shove off. At least, that makes sense to me.

Some of us get there quickly, some of us rather later. Some of us just don't get there fast enough (like people working for the City.) However, death isn't strictly "one to a customer" - while it gets around to you sooner or later, some of us get several visits before it finally sticks...

Click to expand...

Ah yes, now its clear as mud, LOL. Just kidding, I get it now, including this part "Some of us just don't get there fast enough".

Ecomike said:

Ah yes, now its clear as mud, LOL. Just kidding, I get it now, including this part "Some of us just don't get there fast enough".

Click to expand...

Yeah. And then there are the people who hang around long past their "sell by" date...

Euphemisms. They can be fun...

Good information on this thread!

I’ve been battling the dreaded P0455 code, so I’m use to the CIL coming on. Went to clear it at lunch today and there was P0303 in there as well. The XJ ran rough yesterday after a hot restart (5 to 10 minutes). This nails it perfect.

I did two things this weekend that could have brought this on. I put 5 gallons of premium fuel in the tank because the existing fuel was about 2 month old and I thought it might help a little. The higher octane might have added to the heat soak problem. I also replaced the valve cover gasket, which included removing and reinstalling the aluminum shield over the intake and exhaust. I incorrectly thought this was there to help dissipate heat for the center cylinders. Now I know to take it off and throw it away. The 01 XJ does not have anything on #3 injector either. I’ll get the dealer to order this part for me.