Anyone know anything about these?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7909446934&category=33656

 

What is it? Is there a keyword for it so I can look it up? All I got was
this error page from Ebay:

"The item you requested (7909446934) is invalid, still pending, or no longer
in our database. Please check the number and try again. If this message
persists, the item has either not started and is not yet available for
viewing, or has expired and is no longer available."

 

Try this:

http://tinyurl.com/2vy2r

 

this is actually the original one I wanted to post

http://tinyurl.com/2bt6f

 

Well, wish I could help you, but I got nothing for both of those "tinyurl"
pages, prolly cuz I have high security on my pc & those pages (not Ebay's,
though) come up as "restricted sites" on my IE (browser).
Sorry---

;{

 

it reminds me of the thing that you could plug into a wall outlet and "turn
your whole house into a giant TV antenna."

 

I would not waste my money on this.
It's a device(resistor) to alter the O2 sensor's input to the ECU to give
"more performance".

A cold air intake would give better results.I bought my Bomz CAI off
Ebay,$60 postage included.

 

junk

 

it's the tornado fuel saver, and if it worked for shit,
manufacturers would be using them in production.
Chip

 

i just saw the other url. that's an o2 sensor resistor, forces it
into closed loop. unfortunately the ecu doesn't know the real air fuel
mix at that point. if it leans out you buy an engine.
Chip

 

(Chip Stein) wrote in

That would be OPEN loop,when the ECU goes by a preprogrammed map.
(no feedback corrections)

Closed loop is where the ECU uses feedback from the O2 sensor to correct
the mixture,"closing the loop".
(O2 sensor detects lean/rich condition,ECU applies correction[more
fuel/less fuel],then O2 sensor then reads optimal,= a correction loop)

 

putting a resistor in tells the ecu what the 02 level is. thereby
holding it in closed loop. ever watch one with a scan tool? i have,
and they stay in closed loop once the coolant sensor says the engine
is warm.
Chip

 

(Chip Stein) wrote in

You misunderstand what the term "closed loop" means. Closed loop is where
feedback from a sensor is used to generate an opposite response from the
controller,thus bringing the sensor back to 'neutral',maintaining the
closed loop. When you fix(replace) the sensor with a resistor,you have
broken the feedback loop(thus "open loop").The controller gets a fixed or
simulated sensor input and cannot bring the system back to stochiometric.

Now if the resistor goes in series with the O2 sensor,then it offsets the
sensor output,giving a bias.

 

You misunderstand what the term "closed loop" means. Closed loop is where

i don't misunderstand, i've watched these on a live data list, once
the system goes closed loop, it take whatever the o2 reading is and
adjusts fuel trim, both short term and long term. the o2 input is not
required for the ecu to go into closed loop.

 

The URL above does not work.

Are you referring to either of the other two URLs that the original poster
(Lattes) gave? Namely:

http://tinyurl.com/2vy2r which says, among other things, "This is a resistor
that will plug into your AIT (air intake temp) sensor and modify your AIR/Fuel
ratio and slightly change your engine timing to run stronger and with increased
power."

http://tinyurl.com/2bt6f a.k.a. an "intake twister."

If you're referring to the device at Ebay auction site http://tinyurl.com/2vy2r
, then this device modifies the air intake temperature output signal to the ECU.
This signal causes the ECU to modify the fuel injector basic discharge duration.
See http://tinyurl.com/22d46 for more info.

The AIT sensor signal with the ECU comprises an open loop. That is, air intake
temperature changes, the AIT sensor signal changes, and the ECU reads the
changed AIT sensor signal. The ECU then commands a different fuel injector
discharge. There's no feedback to tell the ECU whether it correctly adjusted the
fuel injector discharge in response to the changed AIT.

 

Wouldn't the (OBD-II,since OBD-I has no AIT,AFAIK)primary O2 sensor loop
RE-correct the fuel input to maintain proper mixture,nullifying the AIT
correction?

IOW;the AIT mod changes(adds fuel?) the fuel input,enriching the
mixture,the O2 sensor detects the rich condition,and leans it out by
reducing the fuel input.(to get more power,one has to have more fuel-AIR
mixture,not just more fuel)

Colder,denser air is effectively more air,thus enabling the addition of
more fuel.That;s why cold air intakes give more power,they effectively
increase the amount of fuel-AIR charge to the cylinders.
Fooling the ECU into thinking the air is more dense(colder=more dense)when
it is truly not would only screw up the mixture,making it less optimum.

I suspect the AIT input is for when the engine has not warmed up to
operating temp,when it operates from the pre-programmed map.

 

First, I thought OBD-II was not required until car model year 1996. So my
Chilton's manual for 1984-1995 Civics must be focusingon OBD I emissions
controls. Chilton's indicates that 1988-1995 Civics have an AIT sensor. The
Autozone site at http://tinyurl.com/22d46 suggests the same. Also,
http://www.honda.co.uk/owner/ConcertoManual/index.html indicates the 1991
Concerto (whose engine I believe is identical to the 199 Civic's engine) has an
AIT sensor.

Second, I agree that the O2 sensor kicks in at some point (e.g. after the car
has warmed up and is moving at stead speed) and also modifies the fuel injector
basic discharge duration.

I think "RE-correct" is the correct word here, but "nullify" is not. That is,
suppose the air intake temperature changes. From my reading, the ECU will
respond, and adjust accordingly, the fuel injector basic discharge duration.
Then the O2 sensor reads from the exhaust whatever oxygen content results from
(1) the new air intake temperature and (2) any new discharge duration. The O2
sensor sends its signal reflecting this. This signal doesn't eliminate or
diminish in any way the AIT signal (or any ECU correction response from this
signal), but it may cause further correction of the fuel injector basic
duration.

Two sentences from Chilton's (and Autozone at http://tinyurl.com/22d46 ) keep
leaping out at me:
____
ELECTRONIC CONTROL UNIT (ECU) [for 1991 Civics, among others]
The unit contains memories for the basic discharge duration at various engine
speeds and manifold pressures. The basic discharge duration, after being read
out from the memory, is further modified by signals sent from various sensors to
obtain the final discharge duration.
____

http://www.honda.co.uk/owner/CivicManual/pdf/11-20.pdf has the exact same words
(from "contains" on) for 1995-1997 Civics.

My impression is it's a balancing act.

As you're probably aware, control systems like the PGM-FI system are difficult
to characterize in "step-by-step" fashion. ECU's don't respond slowly and to a
single input at any instant. ECUs are reading input from several sensors at any
time.

From my reading on Civics, I do agree only one input is also feedback (in the
closed-loop sense): The oxygen sensor's.

I agree the AIT sensor signal most likely reflects this.

I'm hesitating a little because there are practical limits as to how cold the
air can be before one has to worry about whether the air-fuel mixture will even
ignite. The colder the air is, the harder it is to ignite, in general. So, yes,
colder air is denser, permitting more fuel to be packed in with it, but only up
until ignition problems enter the picture.

I agree.

I don't know what the overall effect of this Ebay auction device for the AIT
sensor is, but I'd sure be concerned it will screw up something in the car.
Perhaps first the catalytic converter, as I understand (that's the car repair
novice in me speaking) it is vulnerable to "too rich" operating conditions.

I think the AIT input is used all the time, but in general and practically
speaking, when the car is warmed up and cruising at steady speed, any ECU
changes to fuel injector duration are mostly (but not exclusively) due to the O2
sensor.

For example, suppose a person is driving down a Colorado Rockies mountain, and
the air temperature changes markedly. It seems to me the AIT will change the
ECU fuel injector signal, but only in "gross" fashion. That is, the AIT signal
is X at the top of the mountain (50 degrees F) and Y at the bottom of the
mountain (65 degrees F). Once the car is at the bottom and stays at this lower
elevation, where the temperature is pretty steady at about 65 degrees F, the AIT
sensor signal does not change.

Is the car flip-flopping between open loop (no O2 sensor signal) and closed loop
(O2 sensor signal) while driving down such a mountain? I think so, but this
might vary from one make's ECU design to another's. All I can say with
confidence and from my reading is that, in general, when the car is warmed up
and running at steady speed, the car is in closed loop; the oxygen sensor's
signal dominates the ECU's decision-making. But the second someone hits the
accelerator or brake, all bets are off. The car may revert to open loop, by
design.

The only really clear, specific documentation I have for this is Chilton's, the
Autozone site, and the UK manual site. Otherwise, I'm drawing on a lot of
textbook control systems design experience.

 

My mistake;I had thought my GSR lacked the AIT(IAT in the Haynes manual)

I believe too cold of an air temp prevents proper atomization of the fuel
charge,thus more difficult ignition.

Perhaps the AIT input is to get the mix into an approximate range,where the
O2 sensor can fine-tune the mix for optimum? I think once the car warms
up,the under-hood temps will swamp out such air temp changes when driving
thru differing climes.The AIT would only be useful if a REALLY drastic temp
change occurred.

Apologies for not editing down this replay,but I wanted to retain the whole
thing for clarity.

 

From my reading of the manuals, I think this is as good a way as any to put it.

I think you're probably right.

 

shouldn't really be an issue. most modern production cars inject onto
inlet valves that are designed to run hotter than in the old days.
liquid gas on hot metal = very good evaporation!

in addition, the compression stroke raises the temperature of the
fuel/air charge very effectively. i can't recall the numbers now, but
remember, diesels work on the principle of the compressed air being hot
enough to ignite the fuel instantly it's injected. compression in a
gasoline engine is not as highas a diesel so compression temperature
rise is less, but the same principles apply.

"difficult" ignition happens when there is something like an injector
problem where droplets of fuel are entering the cylinder that are too
large to evaporate quickly enough. /that/ causes all kinds of nastiness.

afaik, air temp is monitored all the time. depends on the system i
guess because as you say, some seem only to respond to gross changes,
but in theory, air temp /should/ be monitored all the time - it affects
air density and density affects the amount of fuel that needs to be
injected.

http://www.amazon.com/exec/obidos/ASIN/0837606144/qid=1089585815/sr=2-1/ref=sr_2_1/103-6620766-9100633

is a great book on all kinds of stuff like this.