c

If you're hearing it under no load conditions, then it probably isn't
pinging that you're hearing. Ping usually happens under high load, low RPM
conditions and can be caused by many things including incorrect timing, lean
fuel mixture, lugging the engine in the wrong gear, poor quality fuel or low
octane, carbon buildup in the combustion chamber, oil contaminating the fuel
mixture, and many other things. These are the most common however. I'm
wondering if you're possibly hearing the fuel injectors cycling? Some of
them can be quite noisy.

Chris

"William Oliveri" <wuji@bigvalley.net> wrote in message
news:bl5omp$84bu0$1@ID-193866.news.uni-berlin.de...
> I should mention I hear this the loudest when no torque is applied. That
> is, at idle and between shifting gears. I don't hear it when applying
load
> either light or heavy.
>
> Is pinging more prominent under load? Does it get worse when more load is
> applied?
>
> What does pinging tell about an engine? Does it indicate something
negative
> about an engine?
>
> Thanks
>
>
> bill
>
>
>
> "William Oliveri" <wuji@bigvalley.net> wrote in message
> news:bl5idh$8ap23$1@ID-193866.news.uni-berlin.de...
> > Hi all,
> >
> > I just installed a MPI kit on my 83 CJ7 and all is fine. However,
there
> > is a sound that is coming from the engine which I cannot determine what
it
> > is. To me it sounds like belts moving but not really. Kinda hard to
> > describe. I've heard there's a problem with Pinging with MPI kits.
> >
> > What does pinging sound like? How can I determine if my engine is
> pinging?
> >
> > thanks in advance,
> >
> > bill
> >
> >
>
>

DougW

DougW did pass the time by typing:
> William Oliveri did pass the time by typing:
>> I should mention I hear this the loudest when no torque is applied. That
>> is, at idle and between shifting gears. I don't hear it when applying load
>> either light or heavy.
>
> That doesn't sound like pinging.

Usually I don't follow up one of my posts.. but in this case.


Take a piece of plastic tube and put one end near your ear
and touch the other to the injector. This will isolate
that sound. Just keep your hands out of the fanbelt. :)

--
DougW

DougW

DougW did pass the time by typing:
> William Oliveri did pass the time by typing:
>> I should mention I hear this the loudest when no torque is applied. That
>> is, at idle and between shifting gears. I don't hear it when applying load
>> either light or heavy.
>
> That doesn't sound like pinging.

Usually I don't follow up one of my posts.. but in this case.


Take a piece of plastic tube and put one end near your ear
and touch the other to the injector. This will isolate
that sound. Just keep your hands out of the fanbelt. :)

--
DougW

L.W.(=?iso-8859-1?Q?=DFill?=) Hughes III

Using manifold vacuum and having the initial advance too far
forward will cause it to ping on free wheeling then under a load the
loss of the vacuum will retard the spark for more normal timing.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

DougW wrote:
>

> That doesn't sound like pinging.
>
> Yes and Yes. Although it is more audiable usually at high RPMs.
>
> It means your fuel mix is igniting before it should. In serious cases it can
> burn through the piston and/or throw rods out of an engine.
> In all cases.. ALL CASES.. Pinging is BAD.
>
> Step up one level in octane. i.e run 91 if your runnign 87 and see if the
> problem goes away. You may need to flow more fuel.
>
> The other possibility is your hearing things. :)
>
> --
> -- DougW -- 93 ZJ 4.0 http://members.***.net/wilsond
> HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
> Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors

L.W.(=?iso-8859-1?Q?=DFill?=) Hughes III

Using manifold vacuum and having the initial advance too far
forward will cause it to ping on free wheeling then under a load the
loss of the vacuum will retard the spark for more normal timing.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

DougW wrote:
>

> That doesn't sound like pinging.
>
> Yes and Yes. Although it is more audiable usually at high RPMs.
>
> It means your fuel mix is igniting before it should. In serious cases it can
> burn through the piston and/or throw rods out of an engine.
> In all cases.. ALL CASES.. Pinging is BAD.
>
> Step up one level in octane. i.e run 91 if your runnign 87 and see if the
> problem goes away. You may need to flow more fuel.
>
> The other possibility is your hearing things. :)
>
> --
> -- DougW -- 93 ZJ 4.0 http://members.***.net/wilsond
> HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
> Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors

Simon Juncal

William Oliveri wrote:
> I should mention I hear this the loudest when no torque is applied. That
> is, at idle and between shifting gears. I don't hear it when applying load
> either light or heavy.

That's not pinging... pinging sounds a lot like someone rattling a spray
paint can under your hood as you depress the gas pedal (getting faster
as you rev higher). There's also "knocking" which is much like pinging
both are caused by fuel detonating before or after it SHOULD. I've heard
knock described as sounding like shaking "a coffee can full of marbles".

> Is pinging more prominent under load? Does it get worse when more load is
> applied?

Yes very much so. It's often caused by your engine being starved for air
(overly rich fuel mixture), carbon deposits (they get red hot and become
basically an uncontrolled source of ignition). Fouled plugs (the carbon
on them can glow just like heavy carbon buildup causing the same
pre-ignition problem).


> What does pinging tell about an engine? Does it indicate something negative
> about an engine?

A number of possibilities include; Carbon build up, timing being off or
worn/slipping timing belt/chain, running gas at a lower octane than what
the ignition system is design to use. Air starvation: clogged or dirty
air filter: clogged or malfunctioning air sensors (various types of air
flow sensors such as Mass Air etc.). A dirty enough throttle body, or Carb.

Anyway what you describe isn't likely "ping" but it does sound a lot
like a sticky lifter, if the sound you're hearing is relatively rhythmic
but noticeable mostly when you're parked or moving slowly. It could be a
lifter. If the sound fades slowly in and out sometimes louder sometimes
quite. I'd bet on the lifter.

Simon Juncal

William Oliveri wrote:
> I should mention I hear this the loudest when no torque is applied. That
> is, at idle and between shifting gears. I don't hear it when applying load
> either light or heavy.

That's not pinging... pinging sounds a lot like someone rattling a spray
paint can under your hood as you depress the gas pedal (getting faster
as you rev higher). There's also "knocking" which is much like pinging
both are caused by fuel detonating before or after it SHOULD. I've heard
knock described as sounding like shaking "a coffee can full of marbles".

> Is pinging more prominent under load? Does it get worse when more load is
> applied?

Yes very much so. It's often caused by your engine being starved for air
(overly rich fuel mixture), carbon deposits (they get red hot and become
basically an uncontrolled source of ignition). Fouled plugs (the carbon
on them can glow just like heavy carbon buildup causing the same
pre-ignition problem).


> What does pinging tell about an engine? Does it indicate something negative
> about an engine?

A number of possibilities include; Carbon build up, timing being off or
worn/slipping timing belt/chain, running gas at a lower octane than what
the ignition system is design to use. Air starvation: clogged or dirty
air filter: clogged or malfunctioning air sensors (various types of air
flow sensors such as Mass Air etc.). A dirty enough throttle body, or Carb.

Anyway what you describe isn't likely "ping" but it does sound a lot
like a sticky lifter, if the sound you're hearing is relatively rhythmic
but noticeable mostly when you're parked or moving slowly. It could be a
lifter. If the sound fades slowly in and out sometimes louder sometimes
quite. I'd bet on the lifter.

William Oliveri

I'm curious about carbon build up. Where does carbon build up accumulate
and how is it removed?

Thanks,

bill

"Simon Juncal" <sjuncal@erols.com> wrote in message
news:3F7671C7.5020409@erols.com...
>
>
> William Oliveri wrote:
> > I should mention I hear this the loudest when no torque is applied.
That
> > is, at idle and between shifting gears. I don't hear it when applying
load
> > either light or heavy.
>
> That's not pinging... pinging sounds a lot like someone rattling a spray
> paint can under your hood as you depress the gas pedal (getting faster
> as you rev higher). There's also "knocking" which is much like pinging
> both are caused by fuel detonating before or after it SHOULD. I've heard
> knock described as sounding like shaking "a coffee can full of marbles".
>
> > Is pinging more prominent under load? Does it get worse when more load
is
> > applied?
>
> Yes very much so. It's often caused by your engine being starved for air
> (overly rich fuel mixture), carbon deposits (they get red hot and become
> basically an uncontrolled source of ignition). Fouled plugs (the carbon
> on them can glow just like heavy carbon buildup causing the same
> pre-ignition problem).
>
>
> > What does pinging tell about an engine? Does it indicate something
negative
> > about an engine?
>
> A number of possibilities include; Carbon build up, timing being off or
> worn/slipping timing belt/chain, running gas at a lower octane than what
> the ignition system is design to use. Air starvation: clogged or dirty
> air filter: clogged or malfunctioning air sensors (various types of air
> flow sensors such as Mass Air etc.). A dirty enough throttle body, or
Carb.
>
> Anyway what you describe isn't likely "ping" but it does sound a lot
> like a sticky lifter, if the sound you're hearing is relatively rhythmic
> but noticeable mostly when you're parked or moving slowly. It could be a
> lifter. If the sound fades slowly in and out sometimes louder sometimes
> quite. I'd bet on the lifter.
>

William Oliveri

I'm curious about carbon build up. Where does carbon build up accumulate
and how is it removed?

Thanks,

bill

"Simon Juncal" <sjuncal@erols.com> wrote in message
news:3F7671C7.5020409@erols.com...
>
>
> William Oliveri wrote:
> > I should mention I hear this the loudest when no torque is applied.
That
> > is, at idle and between shifting gears. I don't hear it when applying
load
> > either light or heavy.
>
> That's not pinging... pinging sounds a lot like someone rattling a spray
> paint can under your hood as you depress the gas pedal (getting faster
> as you rev higher). There's also "knocking" which is much like pinging
> both are caused by fuel detonating before or after it SHOULD. I've heard
> knock described as sounding like shaking "a coffee can full of marbles".
>
> > Is pinging more prominent under load? Does it get worse when more load
is
> > applied?
>
> Yes very much so. It's often caused by your engine being starved for air
> (overly rich fuel mixture), carbon deposits (they get red hot and become
> basically an uncontrolled source of ignition). Fouled plugs (the carbon
> on them can glow just like heavy carbon buildup causing the same
> pre-ignition problem).
>
>
> > What does pinging tell about an engine? Does it indicate something
negative
> > about an engine?
>
> A number of possibilities include; Carbon build up, timing being off or
> worn/slipping timing belt/chain, running gas at a lower octane than what
> the ignition system is design to use. Air starvation: clogged or dirty
> air filter: clogged or malfunctioning air sensors (various types of air
> flow sensors such as Mass Air etc.). A dirty enough throttle body, or
Carb.
>
> Anyway what you describe isn't likely "ping" but it does sound a lot
> like a sticky lifter, if the sound you're hearing is relatively rhythmic
> but noticeable mostly when you're parked or moving slowly. It could be a
> lifter. If the sound fades slowly in and out sometimes louder sometimes
> quite. I'd bet on the lifter.
>

c

It builds up on top of the pistons and in the combustion chambers. If an
engine is in good mechanical condition (rings, valve guides, etc.), and is
properly tuned, this isn't usually a problem. Add some oil or too much gas
(rich fuel mixture) and that's when things can go bad. There are
decarburizing chemicals that can be added to gasoline or even poured down
the carb/throttle body. Some old timers used to slowly pour ice water down
the carb while the engine was running, but I personally wouldn't advise
that.

Chris


"William Oliveri" <wuji@bigvalley.net> wrote in message
news:bl5vba$8cspv$1@ID-193866.news.uni-berlin.de...
> I'm curious about carbon build up. Where does carbon build up accumulate
> and how is it removed?
>
> Thanks,
>
> bill
>
> "Simon Juncal" <sjuncal@erols.com> wrote in message
> news:3F7671C7.5020409@erols.com...
> >
> >
> > William Oliveri wrote:
> > > I should mention I hear this the loudest when no torque is applied.
> That
> > > is, at idle and between shifting gears. I don't hear it when applying
> load
> > > either light or heavy.
> >
> > That's not pinging... pinging sounds a lot like someone rattling a spray
> > paint can under your hood as you depress the gas pedal (getting faster
> > as you rev higher). There's also "knocking" which is much like pinging
> > both are caused by fuel detonating before or after it SHOULD. I've heard
> > knock described as sounding like shaking "a coffee can full of marbles".
> >
> > > Is pinging more prominent under load? Does it get worse when more
load
> is
> > > applied?
> >
> > Yes very much so. It's often caused by your engine being starved for air
> > (overly rich fuel mixture), carbon deposits (they get red hot and become
> > basically an uncontrolled source of ignition). Fouled plugs (the carbon
> > on them can glow just like heavy carbon buildup causing the same
> > pre-ignition problem).
> >
> >
> > > What does pinging tell about an engine? Does it indicate something
> negative
> > > about an engine?
> >
> > A number of possibilities include; Carbon build up, timing being off or
> > worn/slipping timing belt/chain, running gas at a lower octane than what
> > the ignition system is design to use. Air starvation: clogged or dirty
> > air filter: clogged or malfunctioning air sensors (various types of air
> > flow sensors such as Mass Air etc.). A dirty enough throttle body, or
> Carb.
> >
> > Anyway what you describe isn't likely "ping" but it does sound a lot
> > like a sticky lifter, if the sound you're hearing is relatively rhythmic
> > but noticeable mostly when you're parked or moving slowly. It could be a
> > lifter. If the sound fades slowly in and out sometimes louder sometimes
> > quite. I'd bet on the lifter.
> >
>
>