Hello,

I have a 98 TJ with the 4.0L engine, with 45,000 miles on it. Just
recently, I'd say, within the past 6 months or so, I started to
develop a noise in my engine. It doesn't happen when at idle, or at
least, I can't hear it. It only happens when the engine is under load.
If I "lug" the engine, this sound is *VERY* apparent. When I first
began to hear it, it was fairly quiet. I had to strain to hear it. (it
was on the highway in a soft-top :) but over time, it's gotten much
louder.

It doesn't happen when the engine is cold. I can drive for about a
half-mile or so, and it will have that great 4.0L purr. but then after
the first half-mile or so, it will begin to make this sound.

I have heard 'pinging' and 'detonation', but really have never had
good examples of what they sound like. (even searched on the net for
..wav files or something) couldn't find anything.

I thought I had a possible cracked exhaust manifold, since I've heard
these are fairly typical on my model TJ, but I took it off and
inspected it and everything looks good.

I've searched around on the newsgroup here, and I'm starting to think
that I've got a ping or detonation, but I don't know exactly what
those are, and what one would do to fix them.. I'd really like to get
to the bottom of it.

Thanks in advance to anybody that can help. It's great that there are
so many friendly and 'eager-to-help a newbie' Jeepers out there.

-Dave

 

If you truly have pinging or detonation going on, the simplest thing to try
is switching gasoline. Try a higher octane rating or even a different brand
to see if it goes away. Outside of that, it could be anything from the
valves needing adjustment, timing correction, or just a plain tune-up
needed. Pinging is typically heard under load and more so in warmer weather.
Pinging has a definite "clattering" sound.

Regards,

GK

"Dave McGlynn" <dpmcglyn@marisaind.com> wrote in message
news:6ad73a15.0404281722.28629e22@posting.google.c om...
> Hello,
>
> I have a 98 TJ with the 4.0L engine, with 45,000 miles on it. Just
> recently, I'd say, within the past 6 months or so, I started to
> develop a noise in my engine. It doesn't happen when at idle, or at
> least, I can't hear it. It only happens when the engine is under load.
> If I "lug" the engine, this sound is *VERY* apparent. When I first
> began to hear it, it was fairly quiet. I had to strain to hear it. (it
> was on the highway in a soft-top :) but over time, it's gotten much
> louder.
>
> It doesn't happen when the engine is cold. I can drive for about a
> half-mile or so, and it will have that great 4.0L purr. but then after
> the first half-mile or so, it will begin to make this sound.
>
> I have heard 'pinging' and 'detonation', but really have never had
> good examples of what they sound like. (even searched on the net for
> .wav files or something) couldn't find anything.
>
> I thought I had a possible cracked exhaust manifold, since I've heard
> these are fairly typical on my model TJ, but I took it off and
> inspected it and everything looks good.
>
> I've searched around on the newsgroup here, and I'm starting to think
> that I've got a ping or detonation, but I don't know exactly what
> those are, and what one would do to fix them.. I'd really like to get
> to the bottom of it.
>
> Thanks in advance to anybody that can help. It's great that there are
> so many friendly and 'eager-to-help a newbie' Jeepers out there.
>
> -Dave

 

If you truly have pinging or detonation going on, the simplest thing to try
is switching gasoline. Try a higher octane rating or even a different brand
to see if it goes away. Outside of that, it could be anything from the
valves needing adjustment, timing correction, or just a plain tune-up
needed. Pinging is typically heard under load and more so in warmer weather.
Pinging has a definite "clattering" sound.

Regards,

GK

"Dave McGlynn" <dpmcglyn@marisaind.com> wrote in message
news:6ad73a15.0404281722.28629e22@posting.google.c om...
> Hello,
>
> I have a 98 TJ with the 4.0L engine, with 45,000 miles on it. Just
> recently, I'd say, within the past 6 months or so, I started to
> develop a noise in my engine. It doesn't happen when at idle, or at
> least, I can't hear it. It only happens when the engine is under load.
> If I "lug" the engine, this sound is *VERY* apparent. When I first
> began to hear it, it was fairly quiet. I had to strain to hear it. (it
> was on the highway in a soft-top :) but over time, it's gotten much
> louder.
>
> It doesn't happen when the engine is cold. I can drive for about a
> half-mile or so, and it will have that great 4.0L purr. but then after
> the first half-mile or so, it will begin to make this sound.
>
> I have heard 'pinging' and 'detonation', but really have never had
> good examples of what they sound like. (even searched on the net for
> .wav files or something) couldn't find anything.
>
> I thought I had a possible cracked exhaust manifold, since I've heard
> these are fairly typical on my model TJ, but I took it off and
> inspected it and everything looks good.
>
> I've searched around on the newsgroup here, and I'm starting to think
> that I've got a ping or detonation, but I don't know exactly what
> those are, and what one would do to fix them.. I'd really like to get
> to the bottom of it.
>
> Thanks in advance to anybody that can help. It's great that there are
> so many friendly and 'eager-to-help a newbie' Jeepers out there.
>
> -Dave

 

If you truly have pinging or detonation going on, the simplest thing to try
is switching gasoline. Try a higher octane rating or even a different brand
to see if it goes away. Outside of that, it could be anything from the
valves needing adjustment, timing correction, or just a plain tune-up
needed. Pinging is typically heard under load and more so in warmer weather.
Pinging has a definite "clattering" sound.

Regards,

GK

"Dave McGlynn" <dpmcglyn@marisaind.com> wrote in message
news:6ad73a15.0404281722.28629e22@posting.google.c om...
> Hello,
>
> I have a 98 TJ with the 4.0L engine, with 45,000 miles on it. Just
> recently, I'd say, within the past 6 months or so, I started to
> develop a noise in my engine. It doesn't happen when at idle, or at
> least, I can't hear it. It only happens when the engine is under load.
> If I "lug" the engine, this sound is *VERY* apparent. When I first
> began to hear it, it was fairly quiet. I had to strain to hear it. (it
> was on the highway in a soft-top :) but over time, it's gotten much
> louder.
>
> It doesn't happen when the engine is cold. I can drive for about a
> half-mile or so, and it will have that great 4.0L purr. but then after
> the first half-mile or so, it will begin to make this sound.
>
> I have heard 'pinging' and 'detonation', but really have never had
> good examples of what they sound like. (even searched on the net for
> .wav files or something) couldn't find anything.
>
> I thought I had a possible cracked exhaust manifold, since I've heard
> these are fairly typical on my model TJ, but I took it off and
> inspected it and everything looks good.
>
> I've searched around on the newsgroup here, and I'm starting to think
> that I've got a ping or detonation, but I don't know exactly what
> those are, and what one would do to fix them.. I'd really like to get
> to the bottom of it.
>
> Thanks in advance to anybody that can help. It's great that there are
> so many friendly and 'eager-to-help a newbie' Jeepers out there.
>
> -Dave

 

If you truly have pinging or detonation going on, the simplest thing to try
is switching gasoline. Try a higher octane rating or even a different brand
to see if it goes away. Outside of that, it could be anything from the
valves needing adjustment, timing correction, or just a plain tune-up
needed. Pinging is typically heard under load and more so in warmer weather.
Pinging has a definite "clattering" sound.

Regards,

GK

"Dave McGlynn" <dpmcglyn@marisaind.com> wrote in message
news:6ad73a15.0404281722.28629e22@posting.google.c om...
> Hello,
>
> I have a 98 TJ with the 4.0L engine, with 45,000 miles on it. Just
> recently, I'd say, within the past 6 months or so, I started to
> develop a noise in my engine. It doesn't happen when at idle, or at
> least, I can't hear it. It only happens when the engine is under load.
> If I "lug" the engine, this sound is *VERY* apparent. When I first
> began to hear it, it was fairly quiet. I had to strain to hear it. (it
> was on the highway in a soft-top :) but over time, it's gotten much
> louder.
>
> It doesn't happen when the engine is cold. I can drive for about a
> half-mile or so, and it will have that great 4.0L purr. but then after
> the first half-mile or so, it will begin to make this sound.
>
> I have heard 'pinging' and 'detonation', but really have never had
> good examples of what they sound like. (even searched on the net for
> .wav files or something) couldn't find anything.
>
> I thought I had a possible cracked exhaust manifold, since I've heard
> these are fairly typical on my model TJ, but I took it off and
> inspected it and everything looks good.
>
> I've searched around on the newsgroup here, and I'm starting to think
> that I've got a ping or detonation, but I don't know exactly what
> those are, and what one would do to fix them.. I'd really like to get
> to the bottom of it.
>
> Thanks in advance to anybody that can help. It's great that there are
> so many friendly and 'eager-to-help a newbie' Jeepers out there.
>
> -Dave

 

I think you're right, you have spark knock, your engine may no
longer run at the correct ignition timing, seeing its controlled be a
computer, we may not reset it from stock without ARB III scanner. So
choose another major fuel, maybe run there higher octane for there
better additives design to clean the injectors and cut the carbon build
that's now retaining the combustion heat and dieseling. Until you find
the right gasoline ease up on the throttle, remember noise equals
damage:
http://www.flavorandfortune.com/pict...s/DSCF1213.jpg
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Dave McGlynn wrote:
>
> Hello,
>
> I have a 98 TJ with the 4.0L engine, with 45,000 miles on it. Just
> recently, I'd say, within the past 6 months or so, I started to
> develop a noise in my engine. It doesn't happen when at idle, or at
> least, I can't hear it. It only happens when the engine is under load.
> If I "lug" the engine, this sound is *VERY* apparent. When I first
> began to hear it, it was fairly quiet. I had to strain to hear it. (it
> was on the highway in a soft-top :) but over time, it's gotten much
> louder.
>
> It doesn't happen when the engine is cold. I can drive for about a
> half-mile or so, and it will have that great 4.0L purr. but then after
> the first half-mile or so, it will begin to make this sound.
>
> I have heard 'pinging' and 'detonation', but really have never had
> good examples of what they sound like. (even searched on the net for
> .wav files or something) couldn't find anything.
>
> I thought I had a possible cracked exhaust manifold, since I've heard
> these are fairly typical on my model TJ, but I took it off and
> inspected it and everything looks good.
>
> I've searched around on the newsgroup here, and I'm starting to think
> that I've got a ping or detonation, but I don't know exactly what
> those are, and what one would do to fix them.. I'd really like to get
> to the bottom of it.
>
> Thanks in advance to anybody that can help. It's great that there are
> so many friendly and 'eager-to-help a newbie' Jeepers out there.
>
> -Dave

 

I think you're right, you have spark knock, your engine may no
longer run at the correct ignition timing, seeing its controlled be a
computer, we may not reset it from stock without ARB III scanner. So
choose another major fuel, maybe run there higher octane for there
better additives design to clean the injectors and cut the carbon build
that's now retaining the combustion heat and dieseling. Until you find
the right gasoline ease up on the throttle, remember noise equals
damage:
http://www.flavorandfortune.com/pict...s/DSCF1213.jpg
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Dave McGlynn wrote:
>
> Hello,
>
> I have a 98 TJ with the 4.0L engine, with 45,000 miles on it. Just
> recently, I'd say, within the past 6 months or so, I started to
> develop a noise in my engine. It doesn't happen when at idle, or at
> least, I can't hear it. It only happens when the engine is under load.
> If I "lug" the engine, this sound is *VERY* apparent. When I first
> began to hear it, it was fairly quiet. I had to strain to hear it. (it
> was on the highway in a soft-top :) but over time, it's gotten much
> louder.
>
> It doesn't happen when the engine is cold. I can drive for about a
> half-mile or so, and it will have that great 4.0L purr. but then after
> the first half-mile or so, it will begin to make this sound.
>
> I have heard 'pinging' and 'detonation', but really have never had
> good examples of what they sound like. (even searched on the net for
> .wav files or something) couldn't find anything.
>
> I thought I had a possible cracked exhaust manifold, since I've heard
> these are fairly typical on my model TJ, but I took it off and
> inspected it and everything looks good.
>
> I've searched around on the newsgroup here, and I'm starting to think
> that I've got a ping or detonation, but I don't know exactly what
> those are, and what one would do to fix them.. I'd really like to get
> to the bottom of it.
>
> Thanks in advance to anybody that can help. It's great that there are
> so many friendly and 'eager-to-help a newbie' Jeepers out there.
>
> -Dave

 

I think you're right, you have spark knock, your engine may no
longer run at the correct ignition timing, seeing its controlled be a
computer, we may not reset it from stock without ARB III scanner. So
choose another major fuel, maybe run there higher octane for there
better additives design to clean the injectors and cut the carbon build
that's now retaining the combustion heat and dieseling. Until you find
the right gasoline ease up on the throttle, remember noise equals
damage:
http://www.flavorandfortune.com/pict...s/DSCF1213.jpg
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Dave McGlynn wrote:
>
> Hello,
>
> I have a 98 TJ with the 4.0L engine, with 45,000 miles on it. Just
> recently, I'd say, within the past 6 months or so, I started to
> develop a noise in my engine. It doesn't happen when at idle, or at
> least, I can't hear it. It only happens when the engine is under load.
> If I "lug" the engine, this sound is *VERY* apparent. When I first
> began to hear it, it was fairly quiet. I had to strain to hear it. (it
> was on the highway in a soft-top :) but over time, it's gotten much
> louder.
>
> It doesn't happen when the engine is cold. I can drive for about a
> half-mile or so, and it will have that great 4.0L purr. but then after
> the first half-mile or so, it will begin to make this sound.
>
> I have heard 'pinging' and 'detonation', but really have never had
> good examples of what they sound like. (even searched on the net for
> .wav files or something) couldn't find anything.
>
> I thought I had a possible cracked exhaust manifold, since I've heard
> these are fairly typical on my model TJ, but I took it off and
> inspected it and everything looks good.
>
> I've searched around on the newsgroup here, and I'm starting to think
> that I've got a ping or detonation, but I don't know exactly what
> those are, and what one would do to fix them.. I'd really like to get
> to the bottom of it.
>
> Thanks in advance to anybody that can help. It's great that there are
> so many friendly and 'eager-to-help a newbie' Jeepers out there.
>
> -Dave

 

I think you're right, you have spark knock, your engine may no
longer run at the correct ignition timing, seeing its controlled be a
computer, we may not reset it from stock without ARB III scanner. So
choose another major fuel, maybe run there higher octane for there
better additives design to clean the injectors and cut the carbon build
that's now retaining the combustion heat and dieseling. Until you find
the right gasoline ease up on the throttle, remember noise equals
damage:
http://www.flavorandfortune.com/pict...s/DSCF1213.jpg
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

Dave McGlynn wrote:
>
> Hello,
>
> I have a 98 TJ with the 4.0L engine, with 45,000 miles on it. Just
> recently, I'd say, within the past 6 months or so, I started to
> develop a noise in my engine. It doesn't happen when at idle, or at
> least, I can't hear it. It only happens when the engine is under load.
> If I "lug" the engine, this sound is *VERY* apparent. When I first
> began to hear it, it was fairly quiet. I had to strain to hear it. (it
> was on the highway in a soft-top :) but over time, it's gotten much
> louder.
>
> It doesn't happen when the engine is cold. I can drive for about a
> half-mile or so, and it will have that great 4.0L purr. but then after
> the first half-mile or so, it will begin to make this sound.
>
> I have heard 'pinging' and 'detonation', but really have never had
> good examples of what they sound like. (even searched on the net for
> .wav files or something) couldn't find anything.
>
> I thought I had a possible cracked exhaust manifold, since I've heard
> these are fairly typical on my model TJ, but I took it off and
> inspected it and everything looks good.
>
> I've searched around on the newsgroup here, and I'm starting to think
> that I've got a ping or detonation, but I don't know exactly what
> those are, and what one would do to fix them.. I'd really like to get
> to the bottom of it.
>
> Thanks in advance to anybody that can help. It's great that there are
> so many friendly and 'eager-to-help a newbie' Jeepers out there.
>
> -Dave

 

It's a long shot, but my catalytic converter, when it first started it's death
rattle, sounded enough like low-end noise (like when you lug the engine bad) to
scare the bejeezus out of me.

-jeff

>I have a 98 TJ with the 4.0L engine, with 45,000 miles on it. Just
>recently, I'd say, within the past 6 months or so, I started to
>develop a noise in my engine. It doesn't happen when at idle, or at
>least, I can't hear it. It only happens when the engine is under load.
>If I "lug" the engine, this sound is *VERY* apparent. When I first
>began to hear it, it was fairly quiet. I had to strain to hear it. (it
>was on the highway in a soft-top :) but over time, it's gotten much
>louder.