4.2L running like a bag of crap
 

I have a 4.2L with a brand new carb(nutters done) and header (feb) it has
run SWEET up until a month ago, now it's running like crap...

It's running really rich, that's the main symptom. Mileage isn't bad but
it's not as good as it was. plugs have about 10K, wires are about a year
old. it doesn't sputter or hesitate and still has great power. It seems to
run closer to normal when it's at operating temp, which makes sense.

Could this be as simple as adjusting the fuel/air mixture? Just seems weird
that "bang" it's running really rich

any help is appreciated

Jason

99% of the time it is the other way, running too lean which acts like
too rich.

Here is a good link to the test and likely fix for it. The tool used
can be obtained at any welding supply shop, it is used for cleaning
torch tips.

http://www.off-road.com/jeep/tech/engine/carter.html

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Pi-Eyed Piper wrote:
>
> I have a 4.2L with a brand new carb(nutters done) and header (feb) it has
> run SWEET up until a month ago, now it's running like crap...
>
> It's running really rich, that's the main symptom. Mileage isn't bad but
> it's not as good as it was. plugs have about 10K, wires are about a year
> old. it doesn't sputter or hesitate and still has great power. It seems to
> run closer to normal when it's at operating temp, which makes sense.
>
> Could this be as simple as adjusting the fuel/air mixture? Just seems weird
> that "bang" it's running really rich
>
> any help is appreciated
>
> Jason

"Pi-Eyed Piper" > wrote in message
news:MS8De.123242$HI.35377@edtnps84...
> I have a 4.2L with a brand new carb(nutters done) and header (feb) it has
> run SWEET up until a month ago, now it's running like crap...
>
> It's running really rich, that's the main symptom. Mileage isn't bad but
> it's not as good as it was. plugs have about 10K, wires are about a year
> old. it doesn't sputter or hesitate and still has great power. It seems to
> run closer to normal when it's at operating temp, which makes sense.
>
> Could this be as simple as adjusting the fuel/air mixture? Just seems
weird
> that "bang" it's running really rich
>
> any help is appreciated
>
> Jason


Is the air cleaner element filthy? Have you looked at the needle-and-seat
assembly in the carb to see if crud is getting past your fuel filter? Have
you actually pulled the plugs to see how they look? Have you been getting
gas at a different station than you used to?

Just a few of the more obvious things to double-check in case you missed
any of them...



-Matt- "..."

ok, I'll check that. With the carb being so new I didn't actually think to
do that, I know these carbs can be troublsome.

Jason
"Mike Romain" > wrote in message
...
> 99% of the time it is the other way, running too lean which acts like
> too rich.
>
> Here is a good link to the test and likely fix for it. The tool used
> can be obtained at any welding supply shop, it is used for cleaning
> torch tips.
>
> http://www.off-road.com/jeep/tech/engine/carter.html
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> Pi-Eyed Piper wrote:
>>
>> I have a 4.2L with a brand new carb(nutters done) and header (feb) it has
>> run SWEET up until a month ago, now it's running like crap...
>>
>> It's running really rich, that's the main symptom. Mileage isn't bad but
>> it's not as good as it was. plugs have about 10K, wires are about a year
>> old. it doesn't sputter or hesitate and still has great power. It seems
>> to
>> run closer to normal when it's at operating temp, which makes sense.
>>
>> Could this be as simple as adjusting the fuel/air mixture? Just seems
>> weird
>> that "bang" it's running really rich
>>
>> any help is appreciated
>>
>> Jason

K&N Filter and it was just cleaned a couple months ago, hasn't been offroad
since. I pulled the plugs when we did the carb, I'll check them again. Gas
at the same place.
"matt borland" > wrote in message
. ..
>
> "Pi-Eyed Piper" > wrote in message
> news:MS8De.123242$HI.35377@edtnps84...
>> I have a 4.2L with a brand new carb(nutters done) and header (feb) it has
>> run SWEET up until a month ago, now it's running like crap...
>>
>> It's running really rich, that's the main symptom. Mileage isn't bad but
>> it's not as good as it was. plugs have about 10K, wires are about a year
>> old. it doesn't sputter or hesitate and still has great power. It seems
>> to
>> run closer to normal when it's at operating temp, which makes sense.
>>
>> Could this be as simple as adjusting the fuel/air mixture? Just seems
> weird
>> that "bang" it's running really rich
>>
>> any help is appreciated
>>
>> Jason
>
>
> Is the air cleaner element filthy? Have you looked at the needle-and-seat
> assembly in the carb to see if crud is getting past your fuel filter? Have
> you actually pulled the plugs to see how they look? Have you been getting
> gas at a different station than you used to?
>
> Just a few of the more obvious things to double-check in case you missed
> any of them...
>
>
>
> -Matt- "..."
>
>

when a vehicle runs lean does temp go up? Mine is still very normal

"Mike Romain" > wrote in message
...
> 99% of the time it is the other way, running too lean which acts like
> too rich.
>
> Here is a good link to the test and likely fix for it. The tool used
> can be obtained at any welding supply shop, it is used for cleaning
> torch tips.
>
> http://www.off-road.com/jeep/tech/engine/carter.html
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> Pi-Eyed Piper wrote:
>>
>> I have a 4.2L with a brand new carb(nutters done) and header (feb) it has
>> run SWEET up until a month ago, now it's running like crap...
>>
>> It's running really rich, that's the main symptom. Mileage isn't bad but
>> it's not as good as it was. plugs have about 10K, wires are about a year
>> old. it doesn't sputter or hesitate and still has great power. It seems
>> to
>> run closer to normal when it's at operating temp, which makes sense.
>>
>> Could this be as simple as adjusting the fuel/air mixture? Just seems
>> weird
>> that "bang" it's running really rich
>>
>> any help is appreciated
>>
>> Jason

While you are in there check the insides of the air tube between the K&N
filter and the carb. The reason you get additional power from K&N style
filters is because they are poor filters. They allow more air and more
dirt/dust than the filter paper type. You can alleviate some of the
problems by installing a pre-filter before the K&N.


"Pi-Eyed Piper" > wrote in message
news:dV9De.95890$wr.69075@clgrps12...
> K&N Filter and it was just cleaned a couple months ago, hasn't been
> offroad since. I pulled the plugs when we did the carb, I'll check them
> again. Gas at the same place.
> "matt borland" > wrote in message

No, is only does it on the idle circuit, once up to speed it runs
normal.

It is from chunks of crud usually found hiding in the steel gas line
between the filter and carb. No one remembers to clean this line. Then
if you run out of gas, it can suck black chunks from the charcoal
canister that cause the same trouble.

Mike

Pi-Eyed Piper wrote:
>
> when a vehicle runs lean does temp go up? Mine is still very normal
>
> "Mike Romain" > wrote in message
> ...
> > 99% of the time it is the other way, running too lean which acts like
> > too rich.
> >
> > Here is a good link to the test and likely fix for it. The tool used
> > can be obtained at any welding supply shop, it is used for cleaning
> > torch tips.
> >
> > http://www.off-road.com/jeep/tech/engine/carter.html
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > Pi-Eyed Piper wrote:
> >>
> >> I have a 4.2L with a brand new carb(nutters done) and header (feb) it has
> >> run SWEET up until a month ago, now it's running like crap...
> >>
> >> It's running really rich, that's the main symptom. Mileage isn't bad but
> >> it's not as good as it was. plugs have about 10K, wires are about a year
> >> old. it doesn't sputter or hesitate and still has great power. It seems
> >> to
> >> run closer to normal when it's at operating temp, which makes sense.
> >>
> >> Could this be as simple as adjusting the fuel/air mixture? Just seems
> >> weird
> >> that "bang" it's running really rich
> >>
> >> any help is appreciated
> >>
> >> Jason

another symptom I just encountered, I honked on it coming out of a parking
lot while grabbing lunch and smelled raw fuel really bad for a few seconds..


"Mike Romain" > wrote in message
...
> No, is only does it on the idle circuit, once up to speed it runs
> normal.
>
> It is from chunks of crud usually found hiding in the steel gas line
> between the filter and carb. No one remembers to clean this line. Then
> if you run out of gas, it can suck black chunks from the charcoal
> canister that cause the same trouble.
>
> Mike
>
> Pi-Eyed Piper wrote:
>>
>> when a vehicle runs lean does temp go up? Mine is still very normal
>>
>> "Mike Romain" > wrote in message
>> ...
>> > 99% of the time it is the other way, running too lean which acts like
>> > too rich.
>> >
>> > Here is a good link to the test and likely fix for it. The tool used
>> > can be obtained at any welding supply shop, it is used for cleaning
>> > torch tips.
>> >
>> > http://www.off-road.com/jeep/tech/engine/carter.html
>> >
>> > Mike
>> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> > 88 Cherokee 235 BFG AT's
>> >
>> > Pi-Eyed Piper wrote:
>> >>
>> >> I have a 4.2L with a brand new carb(nutters done) and header (feb) it
>> >> has
>> >> run SWEET up until a month ago, now it's running like crap...
>> >>
>> >> It's running really rich, that's the main symptom. Mileage isn't bad
>> >> but
>> >> it's not as good as it was. plugs have about 10K, wires are about a
>> >> year
>> >> old. it doesn't sputter or hesitate and still has great power. It
>> >> seems
>> >> to
>> >> run closer to normal when it's at operating temp, which makes sense.
>> >>
>> >> Could this be as simple as adjusting the fuel/air mixture? Just seems
>> >> weird
>> >> that "bang" it's running really rich
>> >>
>> >> any help is appreciated
>> >>
>> >> Jason

Full tank?

Mike

Pi-Eyed Piper wrote:
>
> another symptom I just encountered, I honked on it coming out of a parking
> lot while grabbing lunch and smelled raw fuel really bad for a few seconds..
>
> "Mike Romain" > wrote in message
> ...
> > No, is only does it on the idle circuit, once up to speed it runs
> > normal.
> >
> > It is from chunks of crud usually found hiding in the steel gas line
> > between the filter and carb. No one remembers to clean this line. Then
> > if you run out of gas, it can suck black chunks from the charcoal
> > canister that cause the same trouble.
> >
> > Mike
> >
> > Pi-Eyed Piper wrote:
> >>
> >> when a vehicle runs lean does temp go up? Mine is still very normal
> >>
> >> "Mike Romain" > wrote in message
> >> ...
> >> > 99% of the time it is the other way, running too lean which acts like
> >> > too rich.
> >> >
> >> > Here is a good link to the test and likely fix for it. The tool used
> >> > can be obtained at any welding supply shop, it is used for cleaning
> >> > torch tips.
> >> >
> >> > http://www.off-road.com/jeep/tech/engine/carter.html
> >> >
> >> > Mike
> >> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >> > 88 Cherokee 235 BFG AT's
> >> >
> >> > Pi-Eyed Piper wrote:
> >> >>
> >> >> I have a 4.2L with a brand new carb(nutters done) and header (feb) it
> >> >> has
> >> >> run SWEET up until a month ago, now it's running like crap...
> >> >>
> >> >> It's running really rich, that's the main symptom. Mileage isn't bad
> >> >> but
> >> >> it's not as good as it was. plugs have about 10K, wires are about a
> >> >> year
> >> >> old. it doesn't sputter or hesitate and still has great power. It
> >> >> seems
> >> >> to
> >> >> run closer to normal when it's at operating temp, which makes sense.
> >> >>
> >> >> Could this be as simple as adjusting the fuel/air mixture? Just seems
> >> >> weird
> >> >> that "bang" it's running really rich
> >> >>
> >> >> any help is appreciated
> >> >>
> >> >> Jason