Re: 2003 CR-V engine feels very heavy
 

"TeGGer®" wrote:
> > What years CR-V do the injectors shut off, when you take your foot off
> > the throttle, I was not aware of that.
>
> Every year, make and model of fuel-injected car since about the 80s.

Even some some carburated engines had fuel shut off (before their breed
went extinct). Auto mechanics loved working on those electronically
controlled carburetors...

================================================== =====
A very modest collection of Honda tech info can be found at:
http://www.geocities.com/ng_randolph

Re: 2003 CR-V engine feels very heavy
 

"David and Tracey Mills" <themills.clan@ns.sympatico.ca> wrote in message
news:42292D12.F0DB7075@ns.sympatico.ca...
> If the injectors "shut off", then how does the engine stay running ?
>
> D.Mills - Licensed Automotive Technician.
>
My understanding is that cars made in the last decade or so all do that,
killing injection under lift-throttle conditions above some modest RPM. My
1993 Chevy work truck with manual tranny isn't very smooth about it - I can
feel the difference when using engine braking on steep roads. I think it is
to control emissions rather than to save the bit of fuel that would be used
otherwise.

The cutoff only occurs when the engine doesn't need fuel at the moment. The
injection comes back on as the RPMs drop, so you could say for the time the
injectors are off the engine isn't running, only spinning (and sparking and
pumping). It is restarted, as it were, by its own momentum.

Mike

Re: 2003 CR-V engine feels very heavy
 

"David and Tracey Mills" <themills.clan@ns.sympatico.ca> wrote in message
news:42292D12.F0DB7075@ns.sympatico.ca...
> If the injectors "shut off", then how does the engine stay running ?
>
> D.Mills - Licensed Automotive Technician.
>
My understanding is that cars made in the last decade or so all do that,
killing injection under lift-throttle conditions above some modest RPM. My
1993 Chevy work truck with manual tranny isn't very smooth about it - I can
feel the difference when using engine braking on steep roads. I think it is
to control emissions rather than to save the bit of fuel that would be used
otherwise.

The cutoff only occurs when the engine doesn't need fuel at the moment. The
injection comes back on as the RPMs drop, so you could say for the time the
injectors are off the engine isn't running, only spinning (and sparking and
pumping). It is restarted, as it were, by its own momentum.

Mike

Re: 2003 CR-V engine feels very heavy
 

"Randolph" <trash@junkmail.com> wrote in message
news:42296D7C.4A2BEB00@junkmail.com...
> Even some some carburated engines had fuel shut off (before their breed
> went extinct). Auto mechanics loved working on those electronically
> controlled carburetors...
>
Great! Now I'm going to have Mikuni carburetor nightmares again.

Mike

Re: 2003 CR-V engine feels very heavy
 

"Randolph" <trash@junkmail.com> wrote in message
news:42296D7C.4A2BEB00@junkmail.com...
> Even some some carburated engines had fuel shut off (before their breed
> went extinct). Auto mechanics loved working on those electronically
> controlled carburetors...
>
Great! Now I'm going to have Mikuni carburetor nightmares again.

Mike

Re: 2003 CR-V engine feels very heavy
 

Well for starters, if the engine is multi-point injected, then you
wouldn't be injecting fuel into a throttle......it would be injected
into the intake manifold behind the injector. So, if the injectors "shut
off" while coasting, does that mean when you are accelerating in a
manual trans car that the injectors are "shut off" while changing gears
? I would be inclined to think that instead of the injectors being "shut
off", the pulse width of the injectors would be shortened. Watching a
scan tool (set on injector pulse width display ) while driving, or even
just racing an engine at idle, would show you that the injectors are not
shut off.

D.Mills - Licensed Automotive Technician.

Re: 2003 CR-V engine feels very heavy
 

Well for starters, if the engine is multi-point injected, then you
wouldn't be injecting fuel into a throttle......it would be injected
into the intake manifold behind the injector. So, if the injectors "shut
off" while coasting, does that mean when you are accelerating in a
manual trans car that the injectors are "shut off" while changing gears
? I would be inclined to think that instead of the injectors being "shut
off", the pulse width of the injectors would be shortened. Watching a
scan tool (set on injector pulse width display ) while driving, or even
just racing an engine at idle, would show you that the injectors are not
shut off.

D.Mills - Licensed Automotive Technician.

Re: 2003 CR-V engine feels very heavy
 

Well for starters, if the engine is multi-point injected, then you
wouldn't be injecting fuel into a throttle......it would be injected
into the intake manifold behind the intake valve. So, if the injectors
"shut
off" while coasting, does that mean when you are accelerating in a
manual trans car that the injectors are "shut off" while changing gears
? I would be inclined to think that instead of the injectors being "shut

off", the pulse width of the injectors would be shortened. Watching a
scan tool (set on injector pulse width display ) while driving, or even
just racing an engine at idle, would show you that the injectors are not

shut off.

D.Mills - Licensed Automotive Technician.

Re: 2003 CR-V engine feels very heavy
 

Well for starters, if the engine is multi-point injected, then you
wouldn't be injecting fuel into a throttle......it would be injected
into the intake manifold behind the intake valve. So, if the injectors
"shut
off" while coasting, does that mean when you are accelerating in a
manual trans car that the injectors are "shut off" while changing gears
? I would be inclined to think that instead of the injectors being "shut

off", the pulse width of the injectors would be shortened. Watching a
scan tool (set on injector pulse width display ) while driving, or even
just racing an engine at idle, would show you that the injectors are not

shut off.

D.Mills - Licensed Automotive Technician.

Re: 2003 CR-V engine feels very heavy
 

David and Tracey Mills wrote:
> Well for starters, if the engine is multi-point injected, then you
> wouldn't be injecting fuel into a throttle......

is doesn't matter the location of the injectors - you still have a
throttle on any gasoline engine to control air flow. even "fly by wire"
gasoline engines use throttles.

> it would be injected
> into the intake manifold behind the intake valve. So, if the injectors
> "shut
> off" while coasting, does that mean when you are accelerating in a
> manual trans car that the injectors are "shut off" while changing gears
> ?

they shut off while coasting, i.e. if you take your foot off the gas on
a down grade, slowing down, etc. the map conditions are typically rpm's
over 2k, speed over 30mph, but it varies with different cars.

> I would be inclined to think that instead of the injectors being "shut
>
> off", the pulse width of the injectors would be shortened. Watching a
> scan tool (set on injector pulse width display ) while driving, or even
> just racing an engine at idle, would show you that the injectors are not
>
> shut off.

my analyzer doesn't show zero pulse width either, but then it doesn't
store thousands of points to allow for individual pulse inspection.
besides, you'll almost never see fully shut off injectors while you have
the motor in the workshop.

if you want an example of basic injection systems, including cut-off,
check out:
http://www.nightrider.com/biketech/e...ect_manual.htm
but there's a ton of books & other stuff out there about how these
things work.

also worth checking out is:
http://www.bgsoflex.com/megasquirt.html if you want to roll your own system.

>
> D.Mills - Licensed Automotive Technician.
>

Re: 2003 CR-V engine feels very heavy
 

David and Tracey Mills wrote:
> Well for starters, if the engine is multi-point injected, then you
> wouldn't be injecting fuel into a throttle......

is doesn't matter the location of the injectors - you still have a
throttle on any gasoline engine to control air flow. even "fly by wire"
gasoline engines use throttles.

> it would be injected
> into the intake manifold behind the intake valve. So, if the injectors
> "shut
> off" while coasting, does that mean when you are accelerating in a
> manual trans car that the injectors are "shut off" while changing gears
> ?

they shut off while coasting, i.e. if you take your foot off the gas on
a down grade, slowing down, etc. the map conditions are typically rpm's
over 2k, speed over 30mph, but it varies with different cars.

> I would be inclined to think that instead of the injectors being "shut
>
> off", the pulse width of the injectors would be shortened. Watching a
> scan tool (set on injector pulse width display ) while driving, or even
> just racing an engine at idle, would show you that the injectors are not
>
> shut off.

my analyzer doesn't show zero pulse width either, but then it doesn't
store thousands of points to allow for individual pulse inspection.
besides, you'll almost never see fully shut off injectors while you have
the motor in the workshop.

if you want an example of basic injection systems, including cut-off,
check out:
http://www.nightrider.com/biketech/e...ect_manual.htm
but there's a ton of books & other stuff out there about how these
things work.

also worth checking out is:
http://www.bgsoflex.com/megasquirt.html if you want to roll your own system.

>
> D.Mills - Licensed Automotive Technician.
>

Re: 2003 CR-V engine feels very heavy
 

jim beam wrote:

> David and Tracey Mills wrote:
> > Well for starters, if the engine is multi-point injected, then you
> > wouldn't be injecting fuel into a throttle......
>
> is doesn't matter the location of the injectors - you still have a
> throttle on any gasoline engine to control air flow. even "fly by wire"
> gasoline engines use throttles.
>
> > it would be injected
> > into the intake manifold behind the intake valve. So, if the injectors
> > "shut
> > off" while coasting, does that mean when you are accelerating in a
> > manual trans car that the injectors are "shut off" while changing gears
> > ?
>
> they shut off while coasting, i.e. if you take your foot off the gas on
> a down grade, slowing down, etc. the map conditions are typically rpm's
> over 2k, speed over 30mph, but it varies with different cars.
>
> > I would be inclined to think that instead of the injectors being "shut
> >
> > off", the pulse width of the injectors would be shortened. Watching a
> > scan tool (set on injector pulse width display ) while driving, or even
> > just racing an engine at idle, would show you that the injectors are not
> >
> > shut off.
>
> my analyzer doesn't show zero pulse width either, but then it doesn't
> store thousands of points to allow for individual pulse inspection.
> besides, you'll almost never see fully shut off injectors while you have
> the motor in the workshop.
>
> if you want an example of basic injection systems, including cut-off,
> check out:
> http://www.nightrider.com/biketech/e...ect_manual.htm
> but there's a ton of books & other stuff out there about how these
> things work.
>
> also worth checking out is:
> http://www.bgsoflex.com/megasquirt.html if you want to roll your own system.
>
> >
> > D.Mills - Licensed Automotive Technician.
> >

Well, we'll have to agree to disagree !! I've seen the evidence on hundreds of
cars (mainly Hyundai and Nissan.....Hyundai data is actually faster out of the
scanner than Nissan) and have had many courses about injection architecture and
operation, and I have to work with what I have learned and what I observe in
reality every day.

D.Mills - Licensed Automotive Technician.

Re: 2003 CR-V engine feels very heavy
 

jim beam wrote:

> David and Tracey Mills wrote:
> > Well for starters, if the engine is multi-point injected, then you
> > wouldn't be injecting fuel into a throttle......
>
> is doesn't matter the location of the injectors - you still have a
> throttle on any gasoline engine to control air flow. even "fly by wire"
> gasoline engines use throttles.
>
> > it would be injected
> > into the intake manifold behind the intake valve. So, if the injectors
> > "shut
> > off" while coasting, does that mean when you are accelerating in a
> > manual trans car that the injectors are "shut off" while changing gears
> > ?
>
> they shut off while coasting, i.e. if you take your foot off the gas on
> a down grade, slowing down, etc. the map conditions are typically rpm's
> over 2k, speed over 30mph, but it varies with different cars.
>
> > I would be inclined to think that instead of the injectors being "shut
> >
> > off", the pulse width of the injectors would be shortened. Watching a
> > scan tool (set on injector pulse width display ) while driving, or even
> > just racing an engine at idle, would show you that the injectors are not
> >
> > shut off.
>
> my analyzer doesn't show zero pulse width either, but then it doesn't
> store thousands of points to allow for individual pulse inspection.
> besides, you'll almost never see fully shut off injectors while you have
> the motor in the workshop.
>
> if you want an example of basic injection systems, including cut-off,
> check out:
> http://www.nightrider.com/biketech/e...ect_manual.htm
> but there's a ton of books & other stuff out there about how these
> things work.
>
> also worth checking out is:
> http://www.bgsoflex.com/megasquirt.html if you want to roll your own system.
>
> >
> > D.Mills - Licensed Automotive Technician.
> >

Well, we'll have to agree to disagree !! I've seen the evidence on hundreds of
cars (mainly Hyundai and Nissan.....Hyundai data is actually faster out of the
scanner than Nissan) and have had many courses about injection architecture and
operation, and I have to work with what I have learned and what I observe in
reality every day.

D.Mills - Licensed Automotive Technician.

Re: 2003 CR-V engine feels very heavy
 

David and Tracey Mills wrote:
> jim beam wrote:
>
>
>>David and Tracey Mills wrote:
>>
>>>Well for starters, if the engine is multi-point injected, then you
>>>wouldn't be injecting fuel into a throttle......
>>
>>is doesn't matter the location of the injectors - you still have a
>>throttle on any gasoline engine to control air flow. even "fly by wire"
>>gasoline engines use throttles.
>>
>>
>>>it would be injected
>>>into the intake manifold behind the intake valve. So, if the injectors
>>>"shut
>>>off" while coasting, does that mean when you are accelerating in a
>>>manual trans car that the injectors are "shut off" while changing gears
>>>?
>>
>>they shut off while coasting, i.e. if you take your foot off the gas on
>>a down grade, slowing down, etc. the map conditions are typically rpm's
>>over 2k, speed over 30mph, but it varies with different cars.
>>
>>
>>>I would be inclined to think that instead of the injectors being "shut
>>>
>>>off", the pulse width of the injectors would be shortened. Watching a
>>>scan tool (set on injector pulse width display ) while driving, or even
>>>just racing an engine at idle, would show you that the injectors are not
>>>
>>>shut off.
>>
>>my analyzer doesn't show zero pulse width either, but then it doesn't
>>store thousands of points to allow for individual pulse inspection.
>>besides, you'll almost never see fully shut off injectors while you have
>>the motor in the workshop.
>>
>>if you want an example of basic injection systems, including cut-off,
>>check out:
>>http://www.nightrider.com/biketech/e...ect_manual.htm
>>but there's a ton of books & other stuff out there about how these
>>things work.
>>
>>also worth checking out is:
>>http://www.bgsoflex.com/megasquirt.html if you want to roll your own system.
>>
>>
>>>D.Mills - Licensed Automotive Technician.
>>>
>
>
> Well, we'll have to agree to disagree !! I've seen the evidence on hundreds of
> cars (mainly Hyundai and Nissan.....Hyundai data is actually faster out of the
> scanner than Nissan) and have had many courses about injection architecture and
> operation, and I have to work with what I have learned and what I observe in
> reality every day.
>
> D.Mills - Licensed Automotive Technician.
>
>
i don't think this is a "agree to disagree" issue - this is about the
service tech saying they know more about a system than the guys that
built the stuff in the first place - which is highly unlikely - and
/then/ shutting the book as if there's nothing more to be learned on the
subject.

ignorance is temporary. willful ignorance is not.

Re: 2003 CR-V engine feels very heavy
 

David and Tracey Mills wrote:
> jim beam wrote:
>
>
>>David and Tracey Mills wrote:
>>
>>>Well for starters, if the engine is multi-point injected, then you
>>>wouldn't be injecting fuel into a throttle......
>>
>>is doesn't matter the location of the injectors - you still have a
>>throttle on any gasoline engine to control air flow. even "fly by wire"
>>gasoline engines use throttles.
>>
>>
>>>it would be injected
>>>into the intake manifold behind the intake valve. So, if the injectors
>>>"shut
>>>off" while coasting, does that mean when you are accelerating in a
>>>manual trans car that the injectors are "shut off" while changing gears
>>>?
>>
>>they shut off while coasting, i.e. if you take your foot off the gas on
>>a down grade, slowing down, etc. the map conditions are typically rpm's
>>over 2k, speed over 30mph, but it varies with different cars.
>>
>>
>>>I would be inclined to think that instead of the injectors being "shut
>>>
>>>off", the pulse width of the injectors would be shortened. Watching a
>>>scan tool (set on injector pulse width display ) while driving, or even
>>>just racing an engine at idle, would show you that the injectors are not
>>>
>>>shut off.
>>
>>my analyzer doesn't show zero pulse width either, but then it doesn't
>>store thousands of points to allow for individual pulse inspection.
>>besides, you'll almost never see fully shut off injectors while you have
>>the motor in the workshop.
>>
>>if you want an example of basic injection systems, including cut-off,
>>check out:
>>http://www.nightrider.com/biketech/e...ect_manual.htm
>>but there's a ton of books & other stuff out there about how these
>>things work.
>>
>>also worth checking out is:
>>http://www.bgsoflex.com/megasquirt.html if you want to roll your own system.
>>
>>
>>>D.Mills - Licensed Automotive Technician.
>>>
>
>
> Well, we'll have to agree to disagree !! I've seen the evidence on hundreds of
> cars (mainly Hyundai and Nissan.....Hyundai data is actually faster out of the
> scanner than Nissan) and have had many courses about injection architecture and
> operation, and I have to work with what I have learned and what I observe in
> reality every day.
>
> D.Mills - Licensed Automotive Technician.
>
>
i don't think this is a "agree to disagree" issue - this is about the
service tech saying they know more about a system than the guys that
built the stuff in the first place - which is highly unlikely - and
/then/ shutting the book as if there's nothing more to be learned on the
subject.

ignorance is temporary. willful ignorance is not.