Air Care News
January 1998
New Dynamometers at Air Care Colorado Stations
Envirotest Systems has completed the system-wide renovation of
dynamometers at all Air Care Colorado enhanced emissions testing centers.
The original mechanical inertia sets were replaced with a newer
and simpler electric version in all 72 testing lanes in the Enhanced Program area. Lanes at state-run
Emissions Technical Centers were also equipped with the newer versions.
"The new dynes will greatly increase our efficiency and
greatly decrease the amount of lane down time and customer wait time," said Major Hearn, general
manager for Envirotest's Colorado operations. "We would not have undertaken such a costly project
if we didn't feel motorists would benefit. We're looking forward to a dramatic reduction in wait times
at our stations."
The company estimates that the conversion cost approximately $2
million.
Local media and other interested folks were invited to the Denver
station at 2300 So. Lipan St. on Nov. 20 to see the conversion work in progress. Representatives from
Envirotest and the State of Colorado were on hand to answer questions.
Work crews removed an older, cumbersome mechanical inertia set
from under the concrete floor of a test lane with a crane and lowered in the sleeker, streamlined
electric version.
"Seeing the two pieces of equipment really helps you
understand why we are so excited by this project," said Nancy Reubert, Envirotest's public
information manager. "The old equipment is much heavier and more complicated, with about 60 moving
parts. The new equipment has four moving parts."
Channels 2 and 4 sent camera crews to record the proceedings, and
reporters from the Rocky Mountain News and
Parts and People also attended.
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You told us what you wanted from "Tech Night." We
delivered.
While consistently praising previous Tech Nights for their
strong technical content, participants have criticized the sessions for not providing hands-on
opportunities with vehicles.
So, starting with the Oct.'97 session, the format was changed
to spend more time focusing on fewer vehicles, with live demonstrations in the shop. This has enabled
technicians to see waveforms, components, connectors and hoses on a vehicle, rather than just talk
about them.
Two troublesome vehicles were discussed in detail in October; the
1984-85 Honda Accord and the mid-to-late 80's Toyota Corolla/Nova. Chris Chesney, owner of Traxx
Auto Services in Englewood, covered the Hondas, aided by a Fluke '98 scope and two ailing examples of
Honda's finest. Scott Rill of Burt Toyota presented a very nice Corolla and old Nova. Both presentations
included excellent handouts.
Future Tech Nights will follow a similar format featuring live
diagnoses on one or two specific engine families. Look for Tech Night announcements and themes in your
"Repair Facility Report Card" in the mail about the 10th of the month in January, April,
July and October.
Doug Decker is an environmental protection
specialist for the Colorado Department of Public Health & Environment Air Pollution Control Division,
Small Business Technical Assistance Program.
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Dennis Cooper says he doesn't know everything.
"In our business, we have mechanics who think they know
everything," he said. "We're just the opposite (at Cooper's Automotive). We want to know
everything we can. There is always something more to be learned."
That approach has helped Cooper run a successful, family-owned
business with his wife Kathy for 15 years. It also earned him recognition from his peers as the
outstanding technician in the enhanced program area for the third quarter of 1997.
Cooper's Automotive is a six-bay shop on Public Road in Lafayette.
Two full-time repair technicians, Dale Moser and Doug Oimas, handle most of the day-to-day repairs.
Cooper handles most of the driveability and emissions repair work himself.
"To be honest, fixing driveability problems is almost the
same as fixing emissions problems," he said. "Any type of information on better ways to fix
cars or more accurate ways of doing things helps emissions."
Until 1995, Cooper and his technicians provided emissions test
along with vehicle repairs. The introduction of the centralized testing program that uses the I/M 240
wiped out a chunk of Cooper's business.
"We were a little concerned when the state took away our
emissions testing," Cooper said diplomatically. "But we jumped on the new program bandwagon as
soon as we saw it coming. We already had our FIRST training done before the new emissions ever got here
(the program was introduced in Boulder County in July '95). We wanted our foot in the door from the
very first."
The repair challenges that accompanied the new enhanced test
were apparent to Cooper and his technicians.
"We had to learn more accurate ways of doing things,"
he said. "We know a lot more than we knew two or three years ago. We fix the cars the way they are
supposed to be fixed. And our business is larger because of the lack of backyard neighbors who are able
to fix each other's cars. We are a better repair facility because of the education that we've received
in the new emissions program. We're serving our customers better."
"You've got to change your business to keep up with changes
in technology," he added. "Some people don't want to do that. We're excited about
doing that. If you don't keep up with the times, you won't be in business. I have another 25 years before
I retire. I'm planning on being here."
Dennis Cooper still says he doesn't know everything. His customers
and colleagues know better.
Christopher Dann is the public information
officer for the Air Pollution Control Division, Colorado Department of Public Health & Environment.
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Does the sight of a mid 1980's Ford CFI with a moderate carbon
monoxide failure give your fits? Until recently, no single problem or repair had been identified
for this common failure.
An EEC IV feedback throttle body injected system was installed on
the 3.8 liter V6 and 5.0 liter V8 from 1984 through 1987 in mid-and full-size Ford/Mercury cars.
The system is complex and, when coupled with the car's age and lack of proper maintenance, can be costly
to diagnose and repair.
Here are some tips to help you through it.
First, perform a visual under-hood/under-car inspection for the
obvious -- tampering, external damage, vacuum and wiring integrity, dirty air cleaner, leaks,
etc.
Scan the computer for Key On/Engine Off and Key On/Engine Running
codes. Air management, EGR position, and fuel control codes are very common codes seen with this
emissions package. Correct as necessary.
Next, check to see if the system is controlling fuel. There are
several critical elements to this:
The 3.8 liter CFI system uses two oxygen sensors. The O2 sensors must be switching
together (the 5.0 liter has only one sensor). When viewed on a dual trace scope, the signals
from both sensors should be nearly identical in frequency and amplitude.
Check control at idle by driving the system lean (induce a vacuum leak) and then rich (with
propane).
Check fuel control (O2 switching and bias) at light and medium load.
If the sensors are switching together but the system still is not
in control, check the air switching valve (upstream/downstream). After 30-45 seconds at idle, air will
switch to upstream in order to force the mixture rich for idle quality and catalyst protection. Ensure
that the air system switches downstream off idle. The air management system is controlled by
the TAB (Thermactor Air Bypass) and TAD (Thermactor Air Divert) solenoids located under the coolant
overflow bottle.
Critical inputs to this EEC IV system are:
Coolant temperature
RPM
MAP
O2 sensor
Air Charge temp
Throttle position
EGR valve position
Check each for a proper signal, and also check the other powers
and grounds.
Fuel pressure is critical, as it is on most TBI vehicles.
Specification calls for 39 psi for this application, regulated at the throttle body. Do not confuse
this with the fuel pump pressure specification. It is not uncommon to see regulated fuel pressure
as high as 42-43 psi.
There are a few more items to check -- canister purge solenoid and
operation, injector performance, and catalyst efficiency. Remember, this is an aging Ford and all of
these items are suspect.
Building manifold vacuum works wonders with this system. Ford uses
a frequency-based MAP sensor to determine load, which in turn determines when the system goes into open
loop.
On some worn 3.8 liter cars, this can be as low as 20 m.p.h.
cruise! At our altitude, we lose 3-5 inches of vacuum off the top. An additional 2-4 inches go away on
high mileage engines due to cam and ignition timing slop, carbon buildup, exhaust backpressure and EGR.
Check the timing chain for excessive play and replace if necessary.
Check and reset base timing (up to 4 degrees advanced) from specification. A full carbon treatment may
be needed, based on a boroscope examination. Check and correct exhaust backpressure.
So, you've checked all of the above and the car still emits 30-35
grams of carbon monoxide. What now?
How does the CFI system meter fuel? By varying injector pulse
width while working with a fixed fuel pressure (the 39 psi). By reducing the fuel pressure, you'll reduce
fuel delivery.
Readjust the fuel pressure regulator on the throttle body unit
down to 38 or 37 psi. Do not lower fuel pressure below 37 psi! This simple adjustment will usually bring
a 30-gram car down to around 10-15 grams if everything else is working properly, the system is in control
and the catalyst has not used up its nine lives.
Congratulations! You've now effectively re-jetted the system
to run leaner. Be sure to road test the vehicle, to ensure against hesitation or lean surge complaints.
For additional assistance on this or any other diagnosis, call
your nearest Emissions Technical Center.
Thanks to Chris Chesney, his DTEC crew,
and the Emissions Technical Center staff for researching and documenting this fix!
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