Throttle on a 2008 Elantra

Does my car have a "drive by wire' throttle or a cable arrangement?


---MIKE---

 

Does my car have a "drive by wire' throttle or a cable arrangement?


---MIKE---

Probably, if it does not you'd see the linkage from the pedal leading to the
firewall.

Most cars are going to that sort of setup as computers control so much now,
to keep the engine running at top efficiency. IIRC, Airbus was the first to
use a "fly by wire" system some years ago.

Something we should all do though, is mentally practice what to do if the
throttle malfunctions. Toyota has had 2200 reported instances, 200+
accidents and 18 deaths. You shift into neutral and steer to the side of
the road and stop. I'm sure most of the accidents are due to panic. Be
sure other drivers in your house are aware of what to do.

 

Ed - if you just shift into neutral won't you end up over revving? As I
understand the problem it is a "sticky" throttle and it is my
understanding that a car's brakes can overcome the power of the engine
so my suggestion would be to apply the brakes forcefully, turn the
ignition off, shift to neutral and then turn key back to on to allow
steering (being aware that with the engine off braking and steering will
require more effort) at which point you may pull out of traffic. Of
course this is all easier said then done at the moment of increased
throttle but the first thing is to step on the brake.

 

I believe this was the first use and a number of military aircraft had
fly-by-wire prior to Airbus.

http://disenchanted.com/dis/technology/fly-by-wire.html

I would just depress the clutch.

Matt

 

Virtually all modern engines have rev limiters so this isn't a big concern.

I believe the brakes will overcome most engines, but you would have to
apply them very forcefully as once they become hot you could be in trouble.

It is much safer to do as Ed suggests and shift into neutral so that you
maintain steering and power brakes and don't risk locking the steering
when turning off the engine using the key.

Matt

 

I may have to try stopping while not taking my foot off the gas (right
before I trade it in.
And to think that they used to make cars without power brakes or
steering. How did we ever manage???

 

That was the easy part, the harder thing was starting using
a crank handle and setting a choke.

 

My original question was not answered. Does my car have a "fly by wire"
throttle or not?


---MIKE---

 

I thought you were correct when I first heard about the problem, but
the reports said that some drivers were unable to stop under power.

Most engines will not over rev because of limiters on them, but given
the choice of a $3500 engine or crashing into a tree, you know the
right choice.

 

Do you have a free account on HMAService.com? I lost my info last
week in a computer crash and have not set it up yet. They will show a
diagram of the throttle so you can see.

 

Per HMA instructions:
At some point, there is a cable. Try to follow it to the pedal.
1. Removal the engine cover(A).
2. Disconnect the throttle position sensor(TPS) and the idle speed
actuator(ISA) connectors.
3. Disconnect the positive crankcase ventilation(PCV) hose and the
breather hose.
4. Disconnect the accelerator cable.

Here is some info on the Throttle Position Sensor

The Throttle Position Sensor (TPS) is mounted on the throttle body and
detects the opening angle of the throttle plate. The TPS has a
variable resistor (potentiometer) whose characteristic is the
resistance changing according to the throttle angle. During
acceleration, the TPS resistance between the reference 5V and the
signal terminal decreases and output voltage increases; during
deceleration, the TPS resistance increases and TPS output voltage
decreases. The ECM supplies a reference 5V to the TPS and the output
voltage increases directly with the opening of the throttle valve. The
TPS output voltage will vary from 0.2~0.8V at closed throttle to
4.3~4.8V at wide-open throttle. The ECM determines operating
conditions such as idle (closed throttle), part load,
acceleration/deceleration, and wide-open throttle from the TPS. Also
The ECM uses the Manifold Absolute Pressure Sensor (MAPS) signal along
with the TPS signal to adjust fuel injection duration and ignition
timing.

 

Check the fatality rates per mile driven back then compared to now and
you will see how we managed. We managed by killing many more people per
mile than today.

Also, engines had a lot less power on average back then, speeds were
generally lower and throttles were entirely mechanical so that in the
rare event they stuck (and yes they did as I have had it happen), you
could generally hook your toe under the accelerator and pull it back!

Also, people back then generally knew more about their vehicles (they
had to too keep them running) and knew what to do with a stuck
accelerator. I am still amazed at the family of the, as I recall,
police officer who were killed in the one wreck because the man didn't
have the intelligence to shift into neutral. Personally, I am not
convinced that was an accident. I suspect he decided to take out
himself and his family for some reason that we may never know.

Matt

 

The choke was the easy part, it was the spark advance that took talent!

Matt

 

Yup, that was the hard part. I was gifted at getting it right, my Father
no, so it cost me half an hour sleep
every morning, my Father waked me early to start the farm tractor.

 

I came along after the crank handle but I sure remember having to pull out
the choke.

 

I've read that some manufacturers (Chrysler for one, IIRC) program a brake
override in the computer. In case of signals from brake and accelerator, the
brake wins.
Toyota admits they do not. I wonder if Hyundai does. Anybody know for sure?
HYUNDAITECH?????

 

I had not heard that before about Chrysler, but it sure makes a lot of
sense. As I have stated previously, I have always been impressed with
Chrysler engineering, it is just their manufacturing that has long sucked.

This is similar to the difference in philosophy between Boeing and
Airbus. Boeing has long designed their airplanes to allow the pilot
full control, even to the point of stalling or overstressing the
airplane. At least this was the case up to 10 or so years ago when I
knew engineers at Boeing. It may not be the case anymore. Airbus on
the other hand, chose the philosophy of having the computers limit the
pilot's control authority so as to "protect" the airplane.

The trouble is, in some circumstances it is better to risk airframe
failure or engine failure to avoid some other certain disaster.

Matt

 

This was picked up from the Toyota News group:

This is good news!


---MIKE---

 

Cable from pedal to throttle body.

 

I cannot confirm (nor deny) this.