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Car Forum / Ford / Ford Mustang / November 2004

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electronic throttle?

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Bill Jones - 21 Nov 2004 03:43 GMT
The December issue of Road & Track has a great review on the '05 Mustang GT.

http://www.roadandtrack.com/article.asp?section_id=3&article_id=1662

In it, the reviewer says,

"Response for the first few hundred rpm off idle is soft, the result of only
281 cubic inches, two tons of all-up weight and what must be conservative
engine management.  And while we're griping, electronic throttles are the
work of the financial devil, although we'll admit the Mustang's is the best
yet.  Tuners will have a field day providing crisper off-idle and
snap-throttle operations via computer reflashes and 3.73 gear sets.  The
burnout crowd will not see any progress in losing the throttle cable either.
For the rest of us, the smooth 3-valve makes more power, fewer emissions,
gets the same mileage and lives on 87-octane gasoline."

So, what is electronic throttle?  There's no cable from the gas pedal to the
engine?  Does it really result in softer response at low rpms?

-Bill J.
95 GT
Backyard Mechanic - 21 Nov 2004 03:48 GMT
Bill Jones opined in
news:3aUnd.26690$5b1

> So, what is electronic throttle?  There's no cable from the gas pedal to
> the engine?  Does it really result in softer response at low rpms?

Dunno... but you can pretty well bet it's not a simple potentiometer system
like the TPS... would have to be something that automatically fail-safed.

Imagine the law suits..  
Dinsdale - 21 Nov 2004 04:07 GMT
>Bill Jones opined in
>news:3aUnd.26690$5b1
[quoted text clipped - 6 lines]
>
>Imagine the law suits..  

There are fail-safes, self diagnostics, redundant sensors, and a 'limp
home' mode.

Here's a link to some more info:
http://www.mustangheaven.com/2005mustang/powert.htm

Scroll down about midway to find the throttle section.

DP
http://tinyurl.com/4fcsn
Jim Warman - 21 Nov 2004 04:12 GMT
Yep... no cable. Similar to the system installed on the '04 and up three
valve 5.4 pick ups (and other models, too). It is triple redundant.... most
problems will give limited throttle response and turn on the "wrench light"
on the cluster. There were some problems with a few of the early 5.4s but
they seem to have been ironed out. The ones I have driven took some getting
used to but seem natural, now. The big problem is "tip in" but, as I said,
it is easy to get used to.

First one I drove was in last years Santa Claus parade here in town........
I learned about the tip in response real quick.....

> The December issue of Road & Track has a great review on the '05 Mustang
> GT.
[quoted text clipped - 18 lines]
> -Bill J.
> 95 GT
WindsorFox[SS] - 21 Nov 2004 05:21 GMT
> Yep... no cable. Similar to the system installed on the '04 and up three
> valve 5.4 pick ups (and other models, too). It is triple redundant.... most
[quoted text clipped - 6 lines]
> First one I drove was in last years Santa Claus parade here in town........
> I learned about the tip in response real quick.....

    Tip in? Maybe that's what I am talking about where if you are
stopped or barely moving and you jab the pedal a little too much and
a little too fast you get a holy crap kind of lurch. Now, this is on
a small SUV (XUV) with 280 HP. It seems it would be more than "holy
crap" on a Mustnag with say, 340 RWHP.

Signature

YOU are the real piece of work in this post. I think you are
a couple of drumsticks short of a picnic there bud. - SVTKate

Jim Warman - 21 Nov 2004 06:18 GMT
That's where the problem lies.... from closed throttle to small throttle
openings. This is that area that is much easier to do with a cable than a
wiring harness. Don't forget that we are now at the mercy of computer
dweebs...... these are the guys that can't find the hood release let alone
do what anyone tells them....

>> Yep... no cable. Similar to the system installed on the '04 and up three
>> valve 5.4 pick ups (and other models, too). It is triple redundant....
[quoted text clipped - 12 lines]
> with 280 HP. It seems it would be more than "holy crap" on a Mustnag with
> say, 340 RWHP.
JS - 21 Nov 2004 07:00 GMT
Hey!

I'm a computer dweeb and turn my own wrench too.  Sadly, as much as I love
computers, I think I might rather just have a cable.  The only benefit I can
see is custom programming for drag racers with automatic transmissions to
just hit the throttle on by a push button.  All the computer trickery to
adapt to its surroundings sound nice, but I might rather be able to control
it.  I realize it could do a better job, but the same can be said about
automatics vs. 5-speeds.

I say "might" a lot because I haven't driven a drive-by-wire system yet...

JS

> That's where the problem lies.... from closed throttle to small throttle
> openings. This is that area that is much easier to do with a cable than a
[quoted text clipped - 18 lines]
>> with 280 HP. It seems it would be more than "holy crap" on a Mustnag with
>> say, 340 RWHP.
Jim Warman - 21 Nov 2004 07:51 GMT
I see this as the harbinger of things to come..... firstly, since he PCM
will decide the throttle angle, it can simultaneously decide the correct
fuel and timing setings to achieve the programmers desires. Secondly, it
brings us one step closer to autonomous vehicle control... no driver input
required.

At least we have been all lucky enough to decide our own driving styles.

> Hey!
>
[quoted text clipped - 32 lines]
>>> small SUV (XUV) with 280 HP. It seems it would be more than "holy crap"
>>> on a Mustnag with say, 340 RWHP.
Jim S. - 21 Nov 2004 16:55 GMT
I see it as a thing that is already here. For instance, BMW's valvetronic
system uses intakevalve lift alone to meter air flow. No need for all that
pumping loss. Another area where electronic control of the throttle is
required is for cylinder de-activation. When running on 4 or 6 instead of 8,
more air is going to be required at what would have been the same throttle
position.

>I see this as the harbinger of things to come..... firstly, since he PCM
>will decide the throttle angle, it can simultaneously decide the correct
[quoted text clipped - 42 lines]
>>>> small SUV (XUV) with 280 HP. It seems it would be more than "holy crap"
>>>> on a Mustnag with say, 340 RWHP.
Jim Warman - 22 Nov 2004 00:43 GMT
Actually, the old Cadillac 4/6/8 system (lovingly called 3/5/7 by those of
stricken with these beasts) would have changed air flow requirements. The
modern version is to simply shut off the fuel injector(s) as required
leaving flow through the motor unchanged. Let's not forget that the throttle
plate does exactly what it's name implies..... it chokes off the air supply
into the gasoline motor - of course volumetric effiecency heads for the
toilet and we start to incur pumpng losses. ETC (Electronic Throttle
Control) does nothing to change that. It is simply a new way to achieve an
old result.

I'm not familiar with this BMW system of which you speak but I picture it as
horrendously complex as well as extremely hard to do with only 14 volts.
More common is variable valve timing which may be what you're thinking of.

>I see it as a thing that is already here. For instance, BMW's valvetronic
>system uses intakevalve lift alone to meter air flow. No need for all that
[quoted text clipped - 49 lines]
>>>>> small SUV (XUV) with 280 HP. It seems it would be more than "holy
>>>>> crap" on a Mustnag with say, 340 RWHP.
Jim S. - 22 Nov 2004 01:28 GMT
I do recall reading something about during WWII, people would disconnect
spark plugs in attempt to save rationed fuel. I hope the Cadillac system
worked a bit better than that! ;)

Yeah, an electronic throttle does nothing for pumping loss when applied to
an existing throttle body. I wasn't clear at all in my previous post, sorry.
What I meant was that as an overall system that replaces the throttle body,
an electronic throttle is required and that the whole system is desireable.

Here is a very brief blurb about the BMW system from the SAE website -----

The gasoline-fueled V8 engines powering BMW's new 735i and 745i feature a
combination of three significant "infinitely variable" technologies for
valve timing (via BMW's Double VANOS system), valve lift (Valvetronic), and
intake-tube length-the last an industry-first. These systems enable the V8
in North American tune to produce 242 kW (325 hp) and 447 N.m (330 lb.ft).
Double VANOS (VAriable NOckenwellen Steuerung: German for variable camshaft
control or variable valve timing) steplessly varies intake- and
exhaust-valve timing by 40 and 25?, respectively.

Valvetronic adjusts intake-valve lift infinitely and facilitates breathing
without a throttle butterfly. It adjusts both the effective cam lift and the
opening cross section of the valves via an intermediate lever between the
camshaft and the two intake valves of each cylinder. The distance between
this intermediate shaft and the camshaft is varied infinitely by an
additional, electrically operated eccentric shaft. Via the eccentric shaft,
the lever converts cam movement into valve lifts from 0.3 to 9.7 mm (0.01 to
0.38 in) for idle/deceleration and full power, respectively. Elimination of
the throttle reduces engine-pumping losses, increasing engine efficiency
particularly during low-load operation. Light-load engine operation is
exceptionally smooth due to a relatively small 0.5-2 mm (0.02-0.08) valve
lift. Along with a servomotor and an inductive eccentric-shaft position
sensor, Siemens VDO Automotive provides the Valvetronic controller that
networks with the 40-MHz, 32-bit primary engine computer.

The continuously variable intake manifold consists of two intertwined
helical elements that, when rotated by an electric servomotor, vary the
effective intake length steplessly between 215 and 607 mm (8.5 and 23.9 in).

> Actually, the old Cadillac 4/6/8 system (lovingly called 3/5/7 by those of
> stricken with these beasts) would have changed air flow requirements. The
[quoted text clipped - 64 lines]
>>>>>> a small SUV (XUV) with 280 HP. It seems it would be more than "holy
>>>>>> crap" on a Mustnag with say, 340 RWHP.
Jim Warman - 22 Nov 2004 05:25 GMT
Oh, man..... I can imagine what that must be like to work on. I can't
imagine what it must cost to fix it off warranty...
JS - 21 Nov 2004 17:51 GMT
If one doesn't want to drive to work while driving to work, they should take
public transportation.  If it's not available, they should lobby for it.
Automobiles are part of our lives and passion... to totally automate them
would take away a lot of that.

I've been offered a decent job through my company in NYC, but part of the
stumbling block is that there's nowhere near Manhattan that I think I could
actually enjoy driving.  I'd probably leave the Cobra back here (SW PA) and
just take the beater, for that occasional run to the store.  It would be
rather depressing, actually.

JS

>I see this as the harbinger of things to come..... firstly, since he PCM
>will decide the throttle angle, it can simultaneously decide the correct
[quoted text clipped - 42 lines]
>>>> small SUV (XUV) with 280 HP. It seems it would be more than "holy crap"
>>>> on a Mustnag with say, 340 RWHP.
Backyard Mechanic - 21 Nov 2004 13:43 GMT
Same here... Spent 20 years in the trade but the IMPORTANT part is that I
ended up doing User interface / integration and this reminds me of the new
systems a few years ago that replaced terminal emulation with java and HTML
GUI's ...

I did two call center installations and after spending days building the
screens, was told to pack up before we got tab flow done because the agents
needed to learn to use the mouse... "We'll do tab-flow later, maybe"

For you that say WTF?  heads down people should NEVER use a mouse except for
rare occasions!

Same thing applies here... the thing is done for ease of assembly, PERIOD!!!!
... it doesnt do ANYTHING that couldnt have been done with sidereal sensing
while giving primary control through the cable.

The crap about:
"Because the stiff metal cable between a traditional accelerator pedal and
the engine is eliminated, so is a traditional pathway into the cabin for
noise and vibration."

ranks right up there with

"Magnesium cam covers suppress valve train noise and reduce weight. Taking
weight out at the top of the engine helps lower the car?s center of gravity
and its roll-center axis, improving handling."

as a mistatement of the talking points the Ford engineering group gave the PR  
idiots.

Lighter valve covers = better handling on curves... yep!  Was MEANT to refer
to the lighter heads.

> Hey!
>
[quoted text clipped - 10 lines]
>
> JS
WindsorFox[SS] - 21 Nov 2004 08:21 GMT
> That's where the problem lies.... from closed throttle to small throttle
> openings. This is that area that is much easier to do with a cable than a
> wiring harness. Don't forget that we are now at the mercy of computer

    Imagine the owners of the early FX35 models with the defective
TCM. They would go out and once it does you get NOTHING but idle. The
lucky person had it happen in their driveway / garage, I suppose the
less fortunate had it happen while somewhere on the Interstate....

Signature

YOU are the real piece of work in this post. I think you are
a couple of drumsticks short of a picnic there bud. - SVTKate

WindsorFox[SS] - 21 Nov 2004 05:16 GMT
> So, what is electronic throttle?  There's no cable from the gas pedal to the
> engine?  Does it really result in softer response at low rpms?

    Yes, drive by wire, or at least partially. No, not in my case.
My Nissan will slam you into the seat and send groceries flying if
you aren't careful leaving a light. It's a little strange getting
used to. Now my mom has an RX330 which I think is electronic also and
it doesn't do that, infact it's too light. I'd like to find a happy
medium.

Signature

YOU are the real piece of work in this post. I think you are
a couple of drumsticks short of a picnic there bud. - SVTKate

John - 21 Nov 2004 14:18 GMT
> So, what is electronic throttle?  There's no cable from the gas pedal to
> the engine?  Does it really result in softer response at low rpms?

It sounds like a computer conditioned servo-mechanical circuit.  The airline
industry has used these for years for many reasons like lower weight than
all those cables, facilitate autopilot, record flight commands, and
maintenance is concentrated in just several places (the sender, the
computer, and the receiver) and not the entire length of the cable.  Some
folks think it'll eventually lead to eliminating the co-pilot and later
possibly the pilot.  I have a friend that pilots the big ones on the
Europe/US routes, and he says there is *not* a single, traditional
mechanical cable in it now.  Everything goes thru the computer.

You have to admit it consolidates components for the cruise control real
nice.

I wonder how long throttle commands are stored in the computer and if the
police will ever use it?

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JS - 21 Nov 2004 17:48 GMT
> It sounds like a computer conditioned servo-mechanical circuit.  The
> airline industry has used these for years for many reasons like lower
[quoted text clipped - 5 lines]
> the Europe/US routes, and he says there is *not* a single, traditional
> mechanical cable in it now.  Everything goes thru the computer.

I can see on an airplane or something where there are probably miles of hard
cable, but we're talking a couple foot piece of low-tension cable.  On the
plane, it would be lower weight, easier to assemble, and perhaps cheaper on
the plane, depending on how much it costs to wire it and if it's a bussed
system or single wire per servo.  On the car, it adds ease of assembly and
the possibility to locate the throttle body anywhere on the car (helps the
ram-air systems I guess) without the unsightly cable, but I doubt it'd be
much cheaper.  Yes, the cruise control already operates under the same idea,
but the CC servo can't be remotely capable of what the throttle servo would
need to do - a nearly instantaneous opening of the throttle just isn't in
the typical CC servo's operation capability.  When was the last time your
cruise baked the tires off?  (note that this isn't a shot against you, just
a general rant about the system)

> You have to admit it consolidates components for the cruise control real
> nice.

That it does....

> I wonder how long throttle commands are stored in the computer and if the
> police will ever use it?

Throttle commands are most likely stored to allow the computer to better
respond to the driver and anticipate the next move.  I don't know if the
police will use it... speed logging would be more beneficial than throttle.
There's times you need to floor it... highway onramps, etc.  I'm sure they
could already pull a speed log if they really wanted to.

JS
John - 22 Nov 2004 04:00 GMT
>> It sounds like a computer conditioned servo-mechanical circuit.  The
>> airline industry has used these for years for many reasons like lower
[quoted text clipped - 21 lines]
> (note that this isn't a shot against you, just a general rant about the
> system)

I don't know, it seems very likely to me that one servo could do the job of
both the cruise and throttle function.  Granted, the servo at the throttle
body would have to meet the most demanding requirements, i.e. the throttle
function, but if it could do that doing the cruise part should be a piece of
cake.  I'd bet they are separate functions or subroutines or phases in the
computers program though.  DriveSpy posed the question of one servo below.
Hopefully someone really knows.

>> You have to admit it consolidates components for the cruise control real
>> nice.
[quoted text clipped - 9 lines]
> throttle. There's times you need to floor it... highway onramps, etc.  I'm
> sure they could already pull a speed log if they really wanted to.

You are right on speed logging, I was thinking post-accident investigation.

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Jim Warman - 22 Nov 2004 05:45 GMT
Taken from the 2005 Ford PC/ED manual...... there are two "styles" of
electronic throttle bodies (no mention is made of which goes to which
application) but the difference is in whether the servo-motor is part of the
throttle body or attached separately. The TPS is redundant... one part is
negative slope and the other positive slope. The throttle pedal assembly is
triple redundant..... one negative slope sensor and two positve slope
sensors - the two positive slope sensors share VREF and GND circuits but
have separate SIG-RTNs. No mention is made of an Idle Validation Switch as
found on the diesels (which have been drive by wire for many years, though
they have no throtle plate). There is no IAC and cruise control functions
are through the PCM. During failsafe operation, vehicle speed will be
limited to about 48 mph.

AFAIK, sensor readings are not stored in the PCM... they are simply live
data - read - reacted to and discarded. The restraints control module is
(again AFAIK) still the only place where crash data is stored and it takes a
significant event to initiate the data storage sequence.
John - 22 Nov 2004 11:47 GMT
Thanks Jim!

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> Taken from the 2005 Ford PC/ED manual...... there are two "styles" of
> electronic throttle bodies (no mention is made of which goes to which
[quoted text clipped - 13 lines]
> (again AFAIK) still the only place where crash data is stored and it takes
> a significant event to initiate the data storage sequence.
JS - 22 Nov 2004 05:56 GMT
>>> It sounds like a computer conditioned servo-mechanical circuit.  The
>>> airline industry has used these for years for many reasons like lower
[quoted text clipped - 29 lines]
> phases in the computers program though.  DriveSpy posed the question of
> one servo below. Hopefully someone really knows.

I'm sure that there is only one servo now... would seem senseless to have
two fighting each other.  I was just mentioning that the original servos
that ran the cruise couldn't have dealt with this kind of use/abuse on a
regular basis.  The CC servo lives a pretty easy life comparatively
speaking.

>>> You have to admit it consolidates components for the cruise control real
>>> nice.
[quoted text clipped - 12 lines]
> You are right on speed logging, I was thinking post-accident
> investigation.

Good point.  I'm sure they *could* do it... it's just a matter of if they do
it or not.

JS
John - 22 Nov 2004 11:51 GMT
> I'm sure that there is only one servo now... would seem senseless to have
> two fighting each other.  I was just mentioning that the original servos
> that ran the cruise couldn't have dealt with this kind of use/abuse on a
> regular basis.  The CC servo lives a pretty easy life comparatively
> speaking.

Agreed.

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Rein - 21 Nov 2004 23:22 GMT
>The December issue of Road & Track has a great review on the '05 Mustang GT.
>
[quoted text clipped - 14 lines]
>So, what is electronic throttle?  There's no cable from the gas pedal to the
>engine?  Does it really result in softer response at low rpms?

yup, no cable. There's sensor at the the pedal which measures the
position of the throttle, and there's some sort of servo at the intake
that is controlled by the computer, using the input from your pedal.
Fly/drive by wire, used in almost all new commercial airlines after
airbus started using it.
Now, I have driven a bmw 3 series and I think they have this system
already. Like other people have commented on, slowly accelerating from
a light is harder than on 'wired' cars. Not sure why, it's almost like
a slight delay, then it takes off.

Remove NO-SPAM from email address when replying
DriveSpy - 22 Nov 2004 01:55 GMT
Hey Jim,
  Does the throttle by wire allow Ford to ditch the Idle Air Control actuator
or speed control servo unit and hardware?
Jim Warman - 22 Nov 2004 05:46 GMT
Yes... see my reply to John for some more info....

> Hey Jim,
>   Does the throttle by wire allow Ford to ditch the Idle Air Control
> actuator
> or speed control servo unit and hardware?
 
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