High Hydrocarbons Cause 1989 Oldsmobile to Flunk Emissions Test
Beloved Leader
station wagon, VIN 1G3BP1Y6KRxxxxxx. It has the "Y" code 307 cid (5L)
V8, carburetor, air conditioning, cruise control, and leveling
suspension in the back.The engine management system is the GM CCC
system. The car has only 27,100 miles. Yes, that is low. It was my
parents' car, and it was given to me in the year 2000. It has to pass
the northern Virginia emissions test every two years before I can renew
the registration. Test is conducted under standards set by the Virginia
Department of Environmental Quality; their website is
http://www.deq.state.va.us/mobile/ .
I have the usual hand tools available to me. I also have a timing
light, compression gauge, code scanner, vacuum gauge, dwell tachometer,
several voltmeter/ohmmeters, and some oscilloscopes. I have a few
decades of experience working on cars on an amateur basis. I have
rebuilt the engine and the automatic transmission in my 1976 Cutlass. I
feel comfortable working on cars, but I have come to dread the emission
test, for the reason that I cannot see parts per million or percents of
pollutants in the exhaust.
I had trouble getting this car through this inspection two years ago,
but nothing like what I am encountering now. Then, the problem was high
NOx. I installed a new EGR valve, and a new O2 sensor for good measure.
This year, I took it in for inspection on August 16. The local gas
station has two inspectors, Shakur and Leon. The equipment there is a
treadmill attached to a workstation. The name of the test is the "ASM2
tailpipe emissions inspection." The process is automated, so I figure
that it doesn't matter which inspector is doing the procedure. If you
flunk the first test, you get one free reinspection. All the others
cost $28 each and every time.
For the first test inspector, I had Shakur. The car flunked. Here are
the results:
August 16, 12:46 p.m.
Idle 800 rpm according to the test machine's display.
HC, ppm: 15 mph: limit 55; actual 116 (fail)
HC, ppm, 25 mph: limit 100; actual 138 (fail)
CO, %, 15 mph: limit 0.22; actual 0.06 (pass)
CO, %, 25 mph: limit 0.32; actual 0.08 (pass)
NO, ppm, 15 mph; limit 720; actual 256 (pass)
NO, ppm, 25 mph; limit 700; actual 309 (pass)
Overall test results: fail.
The limit numbers change from year to year, by the way, so if you
happen to have a form from a few years back, you might see different
limit numbers on your form than those that apply in 2006.
When I got back home, I saw that the gas cap, which had been removed
for pressure testing, was missing. The car had been tested with no cap
in place. I went back, thinking that with the cap in place, surely the
car would pass. Shakur had gone for the day. Leon ran the test, and the
car flunked again.
August 16, 4:33 p.m.
Idle 800 rpm according to the test machine's display.
HC, ppm: 15 mph: limit 55; actual 82 (fail)
HC, ppm, 25 mph: limit 100; actual 83 (pass)
CO, %, 15 mph: limit 0.22; actual 0.04 (pass)
CO, %, 25 mph: limit 0.32; actual 0.00 (pass)
NO, ppm, 15 mph; limit 720; actual 232 (pass)
NO, ppm, 25 mph; limit 700; actual 279 (pass)
Overall test results: fail.
"That was your free reinspection," I was told. I didn't think that was
right, as it wasn't my fault that the original test had been run
incorrectly. The next day, Shakur agreed with that and said he would
give me another free test. He said that with a set of new plugs and
wires, the car ought to pass the test. He also said to make sure it was
good and warm when I brought it in.
So I got plugs and wires. As it develops, one of my wires was bad; the
spark plug wire to the #3 cylinder had infinite resistance. Taking a
look at the cap and rotor, I found the rotor also had infinite
resistance. Obviously, the higher voltage present when the rotor was in
use could bridge the open spot in the rotor. The cap had some
corrosion, so I threw in the new cap and rotor as well. I put on a new
air filter too. I checked the timing; it was right, something like 20
degrees BTDC, IIRC. I turned the idle down to 550 rpm, at which speed
the engine was prone to stall. All this was done according to the
procedures specified on the label on the radiator shroud. I went back
for my third test, this time again conducted by Shakur. I drove it in
from the adjacent county, so it was nice and warm. Results:
August 23, 11:06 a.m.
Idle 570 rpm according to the test machine's display.
HC, ppm: 15 mph: limit 55; actual 145 (fail)
HC, ppm, 25 mph: limit 100; actual 232 (fail)
CO, %, 15 mph: limit 0.22; actual 0.06 (pass)
CO, %, 25 mph: limit 0.32; actual 0.23 (pass)
NO, ppm, 15 mph; limit 720; actual 269 (pass)
NO, ppm, 25 mph; limit 700; actual 398 (pass)
Overall test results: fail.
Right. It was worse than before I put on the new parts, a lot worse.
Talk about a sinking feeling. I couldn't work on the car for a while,
but when I got back to it, I took a close look at the hoses. I found
three that were bad, including one with a split about an inch long. One
of the leaking hoses provided vacuum for the cruise control. I replaced
all the bad hoses and dug out my vacuum gauge. I hadn't used one in so
long that I had forgotten how to use it. None of the manuals I could
find had information on its use, but a website told me what I should be
looking for.
"How to Use and Interpret a Vacuum Gauge"
http://www.secondchancegarage.com/public/186.cfm
With the bad hoses replaced, I could get 23 inches vacuum as soon as
the car started, with the engine running at a substantial rpm. The
needle was steady. Satisfied there were no vacuum leaks, I took the car
in for its fourth test. Shakur ran the test. As the car was on the
treadmill, I watched the test machine's display. The screen flashed red
several times before the machine announced that the test was being
aborted due to something called "low flow." That will be $28, said
Shakur.
August 28, 10:33 a.m.
I didn't notice the idle on the test machine's display.
HC, ppm: 15 mph: limit 55; actual N/A (N/A)
HC, ppm, 25 mph: limit 100; actual N/A (N/A)
CO, %, 15 mph: limit 0.22; actual N/A (N/A)
CO, %, 25 mph: limit 0.32; actual N/A (N/A)
NO, ppm, 15 mph; limit 720; actual N/A (N/A)
NO, ppm, 25 mph; limit 700; actual N/A (N/A)
Overall test results: failed/invalid.
Well, what in the world? Shakur said there must be a leak somewhere in
my exhaust. Back home, I rolled the car up onto a set of ramps and
inspected the exhaust. It had been replaced behind the catalytic
converter in about 1999, so it was good and rusted. The metal donut
that goes between the right hand exhaust manifold and the exhaust that
pipe that leads to the catalyic converter had deteriorated and called
for replacement, but there were no gross leaks. The system as basically
tight and leak free.
I got on my bicycle and made the ten minute trip to the Cadillac
dealer. Since some Cadillacs used the 307 motor, I figured they might
have some insight. I couldn't talk to the inspectors until the evening,
and when I went back, I showed them the test results. They told me
right away that the problem with low flow was not with my car, but with
the test machine. An exhaust leak would not cause that condition. I
ought to get another test at no charge.
The next morning, I called the Virginia DEQ and expressed my
frustration with what was going on. I pointed out that I had no problem
with the person running the test; rather, I couldn't understand what
had happened. The person at the DEQ pulled up my test results at his
own terminal and handed it to the DEQ inspector. The inspector said he
couldn't understand the results either, so he went over to the gas
station where the test was being conducted to look at the machine. I
didn't have the time to go down to the gas station to talk to him
there, but he called after he got back to the office and said that
Shakur wanted me to bring the car back in for another free test.
I got back to work on the car. When the weather permitted, I installed
the new metal donut. During that procedure, I broke the air tube that
connects the air injection check valve to the catalytic converter. That
was a special order. Eventually, I had all the parts in place. I got in
the car to drive off the ramps, started it, and put my foot on the
brake pedal. The pedal went all the way to the floor. The rusted brake
line to the left front wheel was obvious. Recall that the car has only
27,100 miles, and you'll understand that the left front wheel could be
so rusted in place that it took two days to remove it. I wanted to
check all my brakes. I found the left rear wheel rusted in place too.
The wheels on the right side were fine. OK, with a one-time extension
on my car's license plates, I went back to the gas station, taking the
long way to get the car warm. I checked the vacuum on the way; it was
21 inches and steady.
October 4, 11:17 a.m.
Idle 538-540 rpm according to the test machine's display.
HC, ppm: 15 mph: limit 55; actual 59 (fail)
HC, ppm, 25 mph: limit 100; actual 79 (pass)
CO, %, 15 mph: limit 0.22; actual 0.01 (pass)
CO, %, 25 mph: limit 0.32; actual 0.04 (pass)
NO, ppm, 15 mph; limit 720; actual 136 (pass)
NO, ppm, 25 mph; limit 700; actual 188 (pass)
Overall test results: fail.
Right. Failed again. At this point I had no idea what to do. I went
back to the Cadillac technician. He suggested pouring into the
carburetor a can of a product that GM sells called "Top Engine
Cleaner." I've used it in this car before, back in 1998 or so. I had
asked him in August if I should try that, but at the time, he had said
it would be a waste of money. Clearly by now his mind had changed. He
also said that after doing that I should "drive the car hard."
Following the instructions on the can, I poured it in. I had
non-automotive chores to take of later that day, so I have not gone for
the brisk drive yet. It was at this point that I composed my post at
sci.electronics.repair and sci.environment. I noticed an old post at
rec.autos.tech in which the poster, discussing a similar situation,
suggested looking at the air injection system. I haven't done anything
along those lines yet.
If the car does not pass, it cannot be registered. A waiver is
possible, but only after I have spent $680 on repairs. The work must be
done by a certified technician at a certified repair facility. All the
work I have done and the parts that I have installed up until now do
not count. According to my latest tax statement, the car's value is
$700. I would probably end up selling the car to someone who lived
outside the area where the test is required. That person would be the
big winner, as he would get a car that would serve him well for years
and years. Inevitably, as the car drives absolutely flawlessly, he
would put not 1500 miles per year on the car, but 1500 miles per month.
The hydrocarbon emissions would still be high, but no one would care. I
would lose a car, and the environment would be worse off.
You now know what I have done in an attempt to get my car through the
emissions test. Please give me your ideas.
Thank you.
Shep
sure you oil is not fuel contaminated, also make sure the evap cannister is
not loaded with fuel also.
"Beloved Leader" <Kim_J...@volcanomail.com> wrote in message
news:1160172391....@i42g2000cwa.googlegroups.com...
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Beloved Leader
Shep wrote:
> High hc's are usually due to raw unburned fuel in the exhaust stream, make
> sure you oil is not fuel contaminated, also make sure the evap cannister is
> not loaded with fuel also.
It's funny you should mention that. Earlier this year, I was certain
that I had a gas tank leak. Due to the cost of gasoline, I never filled
the tank. Rather, I kept only enough gas in the tank to take care of
any errands that may arise. When I parked the car after putting in a
few gallons of gas, there would be a strong odor of gas around the back
of the car. Also, there would be a drop of gasoline on the bottom
outside of the tank. The ground beneath the tank would not be wet with
gasoline, as the drop of gasoline evaporated in place. I thought the
seam where the top half of the tank joins the bottom half of the tank
had rusted through, and I was prepared to replace the tank, at no small
expense.
For the emissions test, I removed the charcoal canister, cleaned its
filter, and cleared out the loose leaves and dirt in the vicinity of
the bottom of the canister. Later I found and replaced three hoses with
holes or a split, eliminating my vacuum leak. To my surprise, once I
did that, I eliminated my gas tank leak too.
I have know for some time that vacuum leaks manifest themselves in
unusual ways, but I was surprised to discover that my gas tank leak was
actually a vacuum leak. At least I dodged the bullet of having to spend
$170 on a new gas tank.
Ancient_Hacker
Beloved Leader wrote:
> I have know for some time that vacuum leaks manifest themselves in
> unusual ways, but I was surprised to discover that my gas tank leak was
> actually a vacuum leak. At least I dodged the bullet of having to spend
> $170 on a new gas tank.
Wait a sec, it's possible to interpret that situation another way:
Before you had a slow gas tank leak, but only when the tank was under
pressure. Most cars pressurize the fuel tank a little bit as part of
their vapor recovery system.
After you messed with the canister, you may have introduced a small air
leak. That would cause the gas tank pressure to drop to zero very
quickly after turning off the engine. Without pressure, the rusty gas
tank seam or whatever doesnt leak. So this "improvement" may actually
be a step backwards. With low or no gas tank pressure, the vapors may
not be getting scavenged by the charcoal canister, and/or the vapors
may not be being purged during normal engine operation. I'd take a
whiff of the canister-- if it smells strongly of gas, it's probably
gas-soaked and needs replacement, or fix the problem in the scavenging
system and run the engine for a few hours and that *might* clean out
the canister. In many cases of a really soaked canister, replacement
is the only viable option.
Beloved Leader
Ancient_Hacker wrote:
> Wait a sec, it's possible to interpret that situation another way:
>
Well, that _would_ be the story of my life.
> I'd take a whiff of the canister--
I'll do that. Thanks for pointing out something I had not considered at
all.
Beloved Leader
Beloved Leader wrote:
> Ancient_Hacker wrote:
> > I'd take a whiff of the canister--
>
> I'll do that. Thanks for pointing out something I had not considered at
> all.
(Later) I opened the hood, leaned in, and took in a big ol' snort.
There is no smell of gasoline in the vicinity of the charcoal canister.
Bonus observation: this canister, and the vacuum supply tank for the
cruise control, are located in what would be the battery tray in a car
with dual batteries. That would be the diesel engine Oldsmobile. I had
never noticed that before.
Thanks again for the suggestion.
Ancient_Hacker
canister end.