Jeeps Canada - Jeep Forums - P0303 and Coolant

Jeeps Canada - Jeep Forums (https://www.jeepscanada.com/)

- Jeep Mailing List (https://www.jeepscanada.com/jeep-mailing-list-32/)

- - P0303 and Coolant (https://www.jeepscanada.com/jeep-mailing-list-32/p0303-coolant-42303/)

Re: P0303 and Coolant

I had a P302 code this summer after a carbon cleaning.

When I pulled spark plug number 2 it looked perfect but when I swirled the
tip in a small vial of some solvent a few particles of carbon were washed
out. I replace the plug and it has worked fine since.

"Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
news:x4qdnTyzJMB2avXYnZ2dnUVZ_uCdnZ2d@comcast.com. ..
>I changed the spark plug today. The one I pulled out looked still brand
>new. No fouling, white ceramic, clean center electrode, gapped at .035. I
>replaced it anyway. I reset the computer and all seems OK for now. I'm sure
>it will come back eventually.
>
> Carl
>
>
> "bllsht" <nospam@dot.net> wrote in message
> news:kishm25j93jjopnqfph9lecfj85h61rfcn@4ax.com...
>> P0303 means the PCM has detected a misfire in the #3 cylinder. Do you
>> see the word SPARK in that definition?
>>
>> HINT
>> There's a lot of things that can cause a misfire, and some things that
>> can cause the PCM to THINK it detects a misfire.
>>
>>
>>
>> On Sat, 25 Nov 2006 12:09:50 -0800, "Jeff Strickland"
>> <crwlr@yahoo.com> wrote:
>>
>>>Yes. What would you deduce from a P0303 code?
>>>
>>>HINT
>>>The code means the #3 plug is not firing properly, which by definition is
>>>a
>>>spark issue.
>>>
>>>
>>>
>>>
>>>
>>>"bllsht" <nospam@dot.net> wrote in message
>>>news:c48hm2hv5ver6p6golf49qrpbsvnspqbp9@4ax.com ...
>>>> So just from the P-code you've already determined it's a spark issue.
>>>> Wow. You're good.
>>>>
>>>>
>>>> On Sat, 25 Nov 2006 09:15:30 -0800, "Jeff Strickland"
>>>> <crwlr@yahoo.com> wrote:
>>>>
>>>>>Relative to the P-code, ALL he needs to address is the spark issue.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>"Earle Horton" <el_anglo_burgues@usa.com> wrote in message
>>>>>news:45686645$0$21225$88260bb3@free.teranews. com...
>>>>>> Heh, I read this as two separate issues. ;^)
>>>>>>
>>>>>> You are right that he needs to address the spark issue too.
>>>>>>
>>>>>> Earle
>>>>>>
>>>>>> "Jeff Strickland" <crwlr@yahoo.com> wrote in message
>>>>>> news:OeudnbF-e-vX7fXYnZ2dnUVZ_oadnZ2d@ez2.net...
>>>>>>> You can drain and refill the coolant all you want -- probably a good
>>>>>>> thing
>>>>>>> by the way -- but this will not fix the error code.
>>>>>>>
>>>>>>> If I got the code you got, I'd be looking at stuff like spark plug
>>>>>>> wires
>>>>>> or
>>>>>>> the coil (if the motor has a dedicated coil for each plug). I
>>>>>>> certainly
>>>>>>> would not spend time and money on completely unrelated systems,
>>>>>>> especially
>>>>>>> when those systems have their own series of codes to tell me when
>>>>>>> they
>>>>>>> are
>>>>>>> not feeling well.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
>>>>>>> news:G9WdnWxDF-WqDPrYnZ2dnUVZ_tidnZ2d@comcast.com...
>>>>>>> > Jeep in question is my 2000 XJ. 4.0, Aw4. 95,000 miles
>>>>>>> >
>>>>>>> > On the way back from Seattle today, I drove down a washboard road
>>>>>>> > for
>>>>>>> > about 7 miles, got gas and went to get back on the highway. Less
>>>>>>> > than
>>>>>> one
>>>>>>> > mile after fueling, I get a CEL. Pull over, gas cap is tight,
>>>>>>> > everything
>>>>>>> > looks OK. Continue around 100 miles home, CEL solid the entire
>>>>>>> > way.
>>>>>>> > Fuel
>>>>>>> > near home, 15.5MPG! I had previously gotten 21.1, 18.9, 20.1.
>>>>>>> >
>>>>>>> > Stop at CSK, pull the codes, and I get P0303. Cylinder number 3
>>>>>>> > misfire.
>>>>>>> > Plugs are new copper champ's, Throttle body was recently removed
>>>>>>> > and
>>>>>>> > cleaned. Any ideas where to start looking?
>>>>>>> >
>>>>>>> > Also, I'm planning on changing the coolant soon. I have heard I
>>>>>>> > can
>>>>>>> > get
>>>>>>> > the prestone heater hose tee, and flush it with a garden hose.
>>>>>>> > Then
>>>>>> drain
>>>>>>> > the radiator thru the lower hose, fill the radiator with distilled
>>>>>> water.
>>>>>>> > Drain again, and refill with 100% coolant. Will this give me the
>>>>>>> > right
>>>>>>> > mixture?
>>>>>>> >
>>>>>>> > Thanks,
>>>>>>> >
>>>>>>> > Carl
>>>>>>> >
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Posted via a free Usenet account from http://www.teranews.com
>>>>>>
>
>

Re: P0303 and Coolant

how did u get the valves to float with the rev limiter in place????

Outatime wrote:

> Jeff Strickland wrote:
>
> > Yes. What would you deduce from a P0303 code?
> >
> > HINT
> > The code means the #3 plug is not firing properly, which by definition
> > is a spark issue.
>
> Not always. A fuel or compression problem in one cylinder will also set
> this code. If you unplug one injector, you'll get it. I've also seen
> 303's thrown if the engine is revved fast enough to induce valve float,
> causing a lack of compression. A fouled plug or bad plug wire should
> always be ruled out first, but other causes can be present as well.

Re: P0303 and Coolant

carbon clening chemicals set that code and i have to erase them after doing a
injection service

billy ray wrote:

> I had a P302 code this summer after a carbon cleaning.
>
> When I pulled spark plug number 2 it looked perfect but when I swirled the
> tip in a small vial of some solvent a few particles of carbon were washed
> out. I replace the plug and it has worked fine since.
>
> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> news:x4qdnTyzJMB2avXYnZ2dnUVZ_uCdnZ2d@comcast.com. ..
> >I changed the spark plug today. The one I pulled out looked still brand
> >new. No fouling, white ceramic, clean center electrode, gapped at .035. I
> >replaced it anyway. I reset the computer and all seems OK for now. I'm sure
> >it will come back eventually.
> >
> > Carl
> >
> >
> > "bllsht" <nospam@dot.net> wrote in message
> > news:kishm25j93jjopnqfph9lecfj85h61rfcn@4ax.com...
> >> P0303 means the PCM has detected a misfire in the #3 cylinder. Do you
> >> see the word SPARK in that definition?
> >>
> >> HINT
> >> There's a lot of things that can cause a misfire, and some things that
> >> can cause the PCM to THINK it detects a misfire.
> >>
> >>
> >>
> >> On Sat, 25 Nov 2006 12:09:50 -0800, "Jeff Strickland"
> >> <crwlr@yahoo.com> wrote:
> >>
> >>>Yes. What would you deduce from a P0303 code?
> >>>
> >>>HINT
> >>>The code means the #3 plug is not firing properly, which by definition is
> >>>a
> >>>spark issue.
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>"bllsht" <nospam@dot.net> wrote in message
> >>>news:c48hm2hv5ver6p6golf49qrpbsvnspqbp9@4ax.com ...
> >>>> So just from the P-code you've already determined it's a spark issue.
> >>>> Wow. You're good.
> >>>>
> >>>>
> >>>> On Sat, 25 Nov 2006 09:15:30 -0800, "Jeff Strickland"
> >>>> <crwlr@yahoo.com> wrote:
> >>>>
> >>>>>Relative to the P-code, ALL he needs to address is the spark issue.
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>"Earle Horton" <el_anglo_burgues@usa.com> wrote in message
> >>>>>news:45686645$0$21225$88260bb3@free.teranews. com...
> >>>>>> Heh, I read this as two separate issues. ;^)
> >>>>>>
> >>>>>> You are right that he needs to address the spark issue too.
> >>>>>>
> >>>>>> Earle
> >>>>>>
> >>>>>> "Jeff Strickland" <crwlr@yahoo.com> wrote in message
> >>>>>> news:OeudnbF-e-vX7fXYnZ2dnUVZ_oadnZ2d@ez2.net...
> >>>>>>> You can drain and refill the coolant all you want -- probably a good
> >>>>>>> thing
> >>>>>>> by the way -- but this will not fix the error code.
> >>>>>>>
> >>>>>>> If I got the code you got, I'd be looking at stuff like spark plug
> >>>>>>> wires
> >>>>>> or
> >>>>>>> the coil (if the motor has a dedicated coil for each plug). I
> >>>>>>> certainly
> >>>>>>> would not spend time and money on completely unrelated systems,
> >>>>>>> especially
> >>>>>>> when those systems have their own series of codes to tell me when
> >>>>>>> they
> >>>>>>> are
> >>>>>>> not feeling well.
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> "Carl" <carlsaiyed@hotmailREMOVE.com> wrote in message
> >>>>>>> news:G9WdnWxDF-WqDPrYnZ2dnUVZ_tidnZ2d@comcast.com...
> >>>>>>> > Jeep in question is my 2000 XJ. 4.0, Aw4. 95,000 miles
> >>>>>>> >
> >>>>>>> > On the way back from Seattle today, I drove down a washboard road
> >>>>>>> > for
> >>>>>>> > about 7 miles, got gas and went to get back on the highway. Less
> >>>>>>> > than
> >>>>>> one
> >>>>>>> > mile after fueling, I get a CEL. Pull over, gas cap is tight,
> >>>>>>> > everything
> >>>>>>> > looks OK. Continue around 100 miles home, CEL solid the entire
> >>>>>>> > way.
> >>>>>>> > Fuel
> >>>>>>> > near home, 15.5MPG! I had previously gotten 21.1, 18.9, 20.1.
> >>>>>>> >
> >>>>>>> > Stop at CSK, pull the codes, and I get P0303. Cylinder number 3
> >>>>>>> > misfire.
> >>>>>>> > Plugs are new copper champ's, Throttle body was recently removed
> >>>>>>> > and
> >>>>>>> > cleaned. Any ideas where to start looking?
> >>>>>>> >
> >>>>>>> > Also, I'm planning on changing the coolant soon. I have heard I
> >>>>>>> > can
> >>>>>>> > get
> >>>>>>> > the prestone heater hose tee, and flush it with a garden hose.
> >>>>>>> > Then
> >>>>>> drain
> >>>>>>> > the radiator thru the lower hose, fill the radiator with distilled
> >>>>>> water.
> >>>>>>> > Drain again, and refill with 100% coolant. Will this give me the
> >>>>>>> > right
> >>>>>>> > mixture?
> >>>>>>> >
> >>>>>>> > Thanks,
> >>>>>>> >
> >>>>>>> > Carl
> >>>>>>> >
> >>>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> --
> >>>>>> Posted via a free Usenet account from http://www.teranews.com
> >>>>>>
> >
> >

Re: P0303 and Coolant

philthy wrote:

> how did u get the valves to float with the rev limiter in place????

The problem actually turned out to be a weak valve spring in an older GC
that hung open if it ran over 3,500 rpm. Referring to this as
'overrevving' was a misnomer; as you mentioned, PCM's won't let you run
the engine beyond OEM-spec redline. It took a LONG time to figure this
one out though.

Re: P0303 and Coolant