taylor25

thanks guys, I will check all the voltages, and will wait to hear what else you can think of before I take the shotgun to it...er I mean bring it to the mechanic!

Complink

ummm are u sure? thats a pretty elaborate resistor then... lol but really its just to reduce turbulence... the vortex generator produces vortices which are recorded as Hz. the temperature sensor is probably what your thinking of

comatose721

iTrader: (16)

i'll scan it up and post it if you want to read it. it's in my UTI text book. i always thought it was meant to do exactly what you said. recently i was reading my textbook again though and it explains what i had posted about it being a resistor.

if you had any interested in reading it i'd be more than happy to send it to you. just let me know and i'll scan it up.

Complink

yeah that would be cool if you could, id like to see it... i always like to learn about stuff like that.

Complink

sorry i couldn't resist...

we have the karman vortex meter btw...

taken from http://www.wellsmfgcorp.com/pdf/Counterpoint3_3.pdf

KARMAN-VORTEX TYPE MASS
AIR-FLOW SENSORS
Another type of mass air-flow sensor that is used
on some Japanese vehicles is a Karman-Vortex
type air-flow sensor. What makes this sensor
different from vane air-flow and hot wire mass airflow
sensors is its unique approach to measuring
air flow.
The advantage of using a Karman-Vortex air-flow
sensor instead of a vane air-flow sensor is that it
causes less restriction. And compared to other
types of mass air-flow sensors, it is simpler and
more reliable, as contamination of the heated
wire or filament in MAF sensors is always a
concern. What’s more, a Karman-Vortex air-flow
sensor can respond more quickly to changes in
air flow than other types of mass air-flow sensors,
which allows the PCM to maintain better control
over the fuel mixture.

HOW IT WORKS
The sensor uses something called the Karman-
Vortex principle to measure air flow. When air
flows past a stationary object, it creates turbulence
or “vortice” (swirling eddies of air) behind the
object. It’s similar to the wake created by a passing
boat. The greater the air flow, the greater the
turbulence. So the sensor measures the amount of
turbulence behind a small object that is placed
in the path of the incoming air to generate an
air-flow signal.
The turbulence is measured electronically one of
two ways: by passing light or sound waves through
the air to detect the changes in pressure, or by
counting the frequency of the pressure changes
(air turbulence). This allows the sensor to generate
a signal that is proportional to air flow.

TOYOTA & LEXUS APPLICATIONS
Karman-Vortex air-flow sensors are used on 1987
and later turbocharged Toyota Supra’s, and all
Lexus engines except the ES 250 and ES 300.
The sensor on these applications has a five-pin
connector and an integral air-temperature sensor.
A light-emitting diode (LED), mirror and photo
receptor are used to count the pressure changes in
these applications. The mirror is mounted on the
end of a very weak leaf spring, which is placed
over a hole leading directly to the area in the sensor
where the vortices form (the “vortex generator”).
Every time a vortex forms, the drop in pressure
wiggles the spring, which causes the reflected light
from the LED to flicker as it is picked up by the
photo receptor. The vibrations of the mirror
produced by the vortices thus causes the light to
flicker on and off in proportion to air flow.
The photo receptor inside the sensor generates
an on-and-off digital signal that varies in frequency
in direct proportion to air flow. At idle when air
flow is low, the signal frequency is also low (about
30 Hz). But as air flow increases, the frequency
of the signal increases. At high speed the signal
may go to 160 Hz or higher.

MITSUBISHI APPLICATIONS
Karman-Vortex air-flow sensors are also used on 1983
and later Mitsubishi’s with turbocharged engines,
and 1987 and later fuel-injected applications.
In the earlier applications, ultrasonics are used
to detect the pressure changes. A small speaker
sends a fixed ultrasonic tone through the vortex
area of the sensor to a microphone. The greater
the number of vortices, the greater the turbulence
and the more the tone is disrupted before it reaches
the microphone. The sensor’s electronics then
translate the amount of tone distortion into a
frequency signal that indicates air flow.
The 1983-86 Mitsubishi sensor has a four-pin
connector while the 1987 to 1990 versions have
a six-pin connector. The early units also contain
an integral air-temperature sensor while the later
ones also contain an integral barometric-pressure
sensor. In 1991, Mitsubishi changed to a redesigned
Karman-Vortex sensor with an eight-pin connector
that replaces the ultrasonic generator with a
pressure sensor that measures fluctuations in air
pressure directly
KARMAN-VORTEX

SENSOR DIAGNOSIS
Both Toyota/Lexus and Mitsubishi Karman-Vortex
air-flow sensors put out two signals: an air-flow
frequency signal and an air-temperature or
barometric-pressure voltage signal. The Karman-
Vortex signal should be a square-wave signal that
flips back and forth from 0 to 5 volts. The frequency
of the signal will increase (narrower pulse width)
as air flow increases. Frequency should increase
smoothly and steadily with rpm.
Driveability problems such as surging, hesitation,
stalling and elevated emissions may indicate a
sensor failure. Most sensor problems are caused
by a loose or corroded wiring connector.
On the early Mitsubishi applications, the sensor is
mounted inside the air cleaner. A poorly fitting
air filter may prevent the air cleaner lid from fully
seating against the sensor and cause problems.
Similar problems can be caused by air leaks in the
intake plumbing or manifold.
Codes 31 & 32 indicate no signal from the air-flow
sensor on the Toyota & Lexus applications. Code
12 refers to a fault in the air-flow sensor circuit
on Mitsubishi applications.

comatose721

iTrader: (16)

good man

i'll try to scan up the part of the chapter tomorrow.

taylor25

ok, well, I decided to give it one more check yesterday, and rechecked the plugs, wires, coils, etc. Took off the CAI, made sure it was clean, checked the throttle to make sure nothing was sticking. When everything got put back together, reconnected the battery wires and let it idle for about 30 min for ecu resetting. Everything was idling correctly. Drove the car down the road, and it started misfiring at idle. At one point I was under the hood, and when I gave it some gas by the throttle, it started idling right again, but when I gave it some more gas, the misfire started back. Hasn't corrected since. So I've got a stutter at 2500-3500 rpm and misfire. DOH. Code for it was P0300. (figures huh) AARRRGHHGHH!!!

Complink

do you have a way to do any logging?

taylor25

Unfortunately no. Could the egr valve cause this? I also checked for vaccum leaks, found none. I know it doesn't have bad gas, I filled it with 93 octane before any of it started.

Complink

i don't know about the egr valve but i would try putting the regular octane back in. temps in your area shouldn't warrant the need for higher octane... unless you have tuned for it

taylor25

I'll give it a try on next tank. I almost want to say that it is a vaccum leak, cause what else would cause such a bad idle misfire. Just can't seem to figure out where it is coming from. On top of everything there is still the original problem of the stutter in the mid rpm.

Complink

if you did have a vacuum leak, the fuel trims would eventually correct for it at idle.

taylor25

Ok, i got the idle took care of. (thank you aluminum pepsi can) I just had to make a temp. gasket for the egr valve. Now back to the skipping/stuttering. Think there is a chance I might have gotten a bad coilpack when I got the new ones?

Thanks

Geo_lancer

iTrader: (1)

try tapping ur maf with ur knucles when the car is on, if shes turns off then its the maf

Complink

you could have a bad injector... when i was tuning my car and it would be real lean in hot weather it would stutter but not as bad when cold.. only way to find out i guess would be to do some logging