Cup Holders

 

 

The Wizard cup holder

The Wizard cup holder

 

 

Oxygen Sensor
Simulator

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Casper Electronics is selling
O2 simulator for OBD2 cars. It is about $40 and I ordered it right away to
compare with my simulator. The simulator from Casper is very small, and nice
looking with 4 wires coming out of it. I connected to battery and looked at the
signal using voltmeter. The signal appeared to be quite similar to signal that
555 timer circuit produced, but appeared more random. It should work. I haven’t
tried on my car, but looking at the signal, it looks even closer to the real O2
data that I had collected earlier. If square wave signal was enough to fool OBD2
MKIV ECU, this one will fool it too. 

http://www.casperselectronics.com/gp/O2SIM/index.htm

 

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What is O2 sensor simulator?
The OBD-II cars (1996-1998) have the two O2 sensors to measure the amount of
oxygen in the exhaust gas. First sensor is measuring it right after gases escape
engine and this data is used to adjust fuel trim of the engine, as well as catch
some faulty conditions. The second sensor is located after the catalic
converter, and is used to detect the health of catalic converter. The ECU
expects the signal from the sensor to be oscillating from below 0.4v to above
0.6v, but not above 1.2v, every few seconds when cruising.

If you install the aftermarket downpipe with no cat (which as we all know is
purely for off-road applications) the ECU will detect this and indicate the
error (MIL). The ECU is quite lazy at detection, and detects this condition
approximately during second long trip. You can reset the ECU to clear the error
code, but it’s very inconvenient, as you don’t really know if the error was
because of oxygen sensor or some important thing is wrong and needs to be taken
care of ASAP. It’s also quite annoying.

 

How to build Your Own Oxygen
Sensor Simulator!
The rest of the page shows how to build an oscillating signal generator with
just the right frequency and voltage to fool the ECU. It is based on classical
astable operating mode of 555 timer, so nothing revolutionary there. However we
spent few days of fiddling and testing to get the right behavior.

The parts will cost about $15 – $20 from RadioShack. It’s not that hard to
build if you have some experience.

Electrical diagram:

Components: 

R1	100 K Ohm
R2	1 M Ohm
R3	100 K Ohm
R4	10 K Ohm
C1	4.7 uF
C2	22 uF
D1	1.7v@20mA LED
D2	1.7v@20mA LED

Hookup:

Power source	Ignition, or to the ECU PIN #1
Ground	One of the ground points or ECU PIN #80
OUT	ECU PIN #47 (disconnect the O2 sensor wire)

Catalog part numbers from RadioShack stores:
(NOT for their online
system)

276-309	5mm wide angle red led 1.7v, 20mA
276-1723	The 555 programmable timer
276-1995A	The 8 pin socket for timer chip. It makes soldering safer and replacement easier
276-150A	Generic PC board
64-3052A	Pack of blue tap-in connectors
278-1225	Stranded wires (black, red and green)
270-1801	Small black plastic project box 3 x 2 x 1
272-1024	Capacitor, 4.7uF
272-1026	Capacitor, 22uF

 

Additional notes:
If you use different flavors of 555 timer chip or LEDs with different
parameters you will need to readjust the values of R4 and R2 to get the interval
and output voltage right.

Don’t attach it directly to the ECU right after assembly. Instead attach it
to the battery and check the output. You should get approximately 0v/0.7v
flipping about every 3.3 seconds when the car is not running, and 0v/0.9v when
the car is running. The current should stay below 10mA.

One LED should be always on whenever the power is supplied. Another LED
indicates when the output signal is high, so it should go on and off with the
signal.

When tapping the ECU wires, triple check everything before hooking up the
oscillator. The power source should read 0v when the key is removed, about 12.6v
when they key is at ACC and about 14.3 when the alternator is running. The
resistance between ground wire and the body shield of the ECU should be 0 ohms.
And it would be best if you run the car and monitor the voltage of the original
oxygen sensor wire before cutting it to make sure you have indeed got the right
one. The resistance between ECU PIN
#47 and ground is about 1.3 to 1.6 M Ohm.

The original sensor should still be dangling around, or plugged into the
downpipe. The reason is that ECU also monitors the resistance of heater circuit
inside the sensor. If you want to COMPELTELY disconnect it, you will need to
measure the resistance of the heater circuit and install the right resistor
between ECU PIN
#72 and ECU PIN
#31 Anyway, there is no need to do it if you just leave O2 sensor alone and
only intercept the oxygen signal wire.

Above testing and precautions will prevent you from frying the ECU and
spending major $$$$. Anyway, I assume no responsibility if you still manage to
do so.

Thanks to:

Mohd A, providing documentation
Nick P, running the
www.mkiv.com list,
Oolan Zimmer,
encouraging (and testing)
Steve V., RadioShack part numbers
Tovar
Millhollin, testing the prototype

Any
Feedback is welcome!

 

 

ÿØÿà

TRAC Off Light + MIL + Cruise
Control Dropouts + No ABS Lamp

By John Cribb

These are mysterious, patient but well known and related problems
with MKIV Supra’s caused by cold solder joints or broken traces on certain
printed circuit boards in the dash warning lamp clusters.

Symptoms:

• The TRAC Off lamp may illuminate from time to time
  accompanied by a dimly lit MIL
• Cruise control may stop working
• Engine warning lamps in left hand side dash pod may or
  may not work at all
• Any or all of these conditions can be manifested by
  giving either the left or right hand Warning Lamp cluster a sharp couple of
  raps with the knuckles, or pressing on them with 2-3 fingers.

 

The Fix:

• Removal of engine Warning Lamp pods from dash, and a
  “touch up” of all exposed solder joints, along with inspection and repair of
  any broken printed circuit traces.

 

Tools Needed:

• For the Warning Lamp cluster removal, one normal length
  #2 Philips screwdriver, and one “shorty” #2 Philips are all that are required.
  Magnetic tips are your friends here.
• For the soldering job, a well lit work area, a 25 watt
  pencil tip soldering iron, and some rosin core (not acid core) soldering paste
  or flux, are required, along with 1-2 flat wooden toothpicks. The 25 watt
  pencil tip iron is just about perfect for this job as it melts the solder
  joints quickly, but doesn’t overheat or burn the board. A 15 watt iron doesn’t
  apply enough heat and this will cause “cold” solder joints, while a 50 watt
  iron will scorch the board. The toothpicks will be used to apply the rosin
  flux to the solder joints.

 

Warning Lamp cluster removal:

• First, disconnect the negative battery terminal to
  prevent airbags from inadvertently going off and/or accidental short-circuits
  from occurring.
• Next, get the soldering iron plugged in and heating up.
  The cluster removal won’t take more than 10-15 minutes.

 

Now, looking up under the instrument cluster, notice there
are five (5) screws. Remove these:

 

This upper trim piece with the left & right warning lamp
pods & odometer can now be pulled away from the dash:

 

Very carefully pull this piece away from the dash until the
connectors are exposed for the right & left warning lamp pods. Find the spring
releases on these connectors and release the harness and unplug the assembly. Do
not force anything here! Once you properly release the spring catches on the
connectors, they should unplug fairly easily. Do not pull on the wires
themselves, only the plugs & sockets:

 

Once the trim piece with lamp pods has been removed, it’s
time to take the lamp pods off and disassemble. Here is a photo of the left hand
pod where most of the problems occur:

 

Remove the black screws first, which hold the pod to the
trim, then remove the brass screws which will expose the two printed circuit
boards. Disassemble the unit.

 

Gently spread the boards apart to expose the solder
connections. Note how the main connector for the module is mechanically fastened
to the board by its solder joints – this is one weak spot, with the connections
for the ribbon cable also being suspect:

 

Now, apply a thin coating of rosin core flux to all the
exposed solder joints and “touch” each one with the soldering iron so that the
solder becomes molten again and flows through the joint. Leave the iron on the
joint only long enough to ensure the solder has reflowed, then remove it. Do not
jar or move the assembly for at least 5-10 seconds after removing the iron, as
this may result in a “cold” joint. If you have done this properly you should be
rewarded with a shiny new solder joint. Note, it must be gleaming & shiny – if
it looks dull, then you moved it while it was solidifying, didn’t heat it
enough, or you forgot to use the rosin flux to keep the joint clean. The use of
rosin flux is MANDATORY for this work. The high heat of soldering causes rapid
oxidation of the metal – oxidation leads to poor bonding, and poor bonding means
cold solder joints. If your joints are not shiny, you must do them again.

Repeat this process for each exposed solder joint, then
clean the excess flux off the board with a clean rag or paper towel and inspect
your work closely. Make sure all new solder joints are clean and shiny, and
ensure that no joints have accidentally shorted together by “bridging”.

If you have access to a good light source and a magnifying
glass, it may be useful to inspect the board traces closely for any evidence of
cracking or breakage as some owners have reported problems with broken traces on
their boards rather than just cold solder joints. If any broken traces are
noted, the break can usually be bridged by applying a “very” small bit of solder
at the point of the break. Keep in mind that less is best! Only apply a small
bit of solder to the tip of the iron – not even enough to make a visible “drip”
on the tip, then apply the tip to the broken trace and let the solder “heal” the
break.

 

Once you are happy with this cluster, repeat the process
for the right hand odometer cluster. Note how many more connections it has due
to the display:

 

Finally, reassemble both Warning Lamp clusters in their
pods and into the trim piece, reconnect the wiring harness and reinstall the
trim piece into the dash. Note this trim piece has several pin & sleeve type
locators on both the left & right sides, as well as the top of the gauge
cluster. Make sure these pin & sleeve points are mated correctly as the piece
will not fit otherwise and/or something will break. Replace the five (5) black
trim screws, reconnect the negative battery terminal and you’re ready to test
your work.

Start the car, noting that the ABS lamp will stay on in the
left-hand pod for two seconds after the ignition is turned on (this is the ABS
self test). After this, confirm that all warning lamps have extinguished and the
car is running OK. Give both left & right pods a couple of sharp raps with your
knuckles, or apply finger pressure and see if a MIL can be produced. If this
procedure produced a MIL previously, and does not now, congratulations! Take the
car for a spin, over some railroad tracks if possible, or other rough surface
and continue to give the left & right pods some sharp raps and watching for
MIL’s or other warning lamps.

If any new Warning Lamps or MIL’s are illuminated, you may
have to disassemble the dash, pull out the instrument cluster, and resolder the
joints on this assembly just as you did for the Warning Lamp pods.

0&²uŽfÏ

RIFFÒE