EPA-AA-TSS-I/M-86-7
Technical Report
The Results of Plumbtesmo Tailpipe
Testing on Ten Vehicles Misfueled with
0.1 gin/gal Leaded Gasoline
By
Edward L. Glover
September 1986
NOTICE
Technical Reports do not necessarily represent final EPA
decisions or positions. They are intended to present
technical analysis of issues using data which are
currently available. The purpose in the release of such
reports is to facilitate the exchange of technical
information and to inform the public of technical
developments which may form the basis for a final EPA
decision, position or regulatory action.
Technical Support Staff
Emission Control Technology Division
Office of Mobile Sources
Office of Air and Radiation
U. S. Environmental Protection Agency
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1.0 INTRODUCTION
This report is intended to present the results of a
rv.isfueling study done by Automotive Testing Labs under EPA
contract. This study was performed to evaluate the performance
of Plumbtesmo brand lead sensitive paper in detecting the
presence of lead on vehicle tailpipes after the vehicles were
misfueled with 0.10 + 0.02 grams/gal leaded fuel (low lead
fuel). Gasoline with this lead content is the new standard
(Federal Register 50 FR 9386) and will eventually be the only
leaded gasoline available in the marketplace. However,
currently, because of lead "Banking" credits, the lead content
of gasoline varies between 0.1 grams/gal and 1.0 grams/gal and
currently averages about 0.3 grams/gal.
In several vehicle inspection/maintenance (I/M) programs
lead-sensitive test paper is used to detect water soluble lead
deposits in tailpipes. Concern has developed as to whether the
test paper can still be used in I/M programs to detect the
presence of lead deposits resulting from the use of the reduced
lead content gasoline. This report will address this question.
2.0 CONCLUSIONS
Previous EPA studies (ref. 2) on continuous misfueling
with leaded gasoline indicate that from one to six tanks of
leaded gasoline at 1.0 gram/gal are required to initiate a
positive Plumbtesmo reaction. The results of this present
study indicate that Plumbtesmo can also detect the presence of
lead in tailpipes following misfueling with 0.1 gram/gal
gasoline. The number of continuous misfueling episodes is
still from one tank to about six tanks of the reduced lead
content fuel with most vehicles showing a positive reaction
after only four tanks. The testing also showed that Plumbtesmo
could be used to detect the results of misfueling on oxygen
sensors and spark plug electrodes after fueling with unleaded
fuel for an extended period of time.
3.0 TEST VEHICLES
Ten vehicles were tested in this study. Each vehicle was
a 1981 or newer gasoline-fueled passenger vehicle equipped with
a three-way catalyst (with or without an additional oxidation
catalyst) and close-loop configuration. All vehicles had
accumulated at least 4000 miles prior to the tests. The test
vehicles used were screened for absence of indications of
previous leaded fuel use. Screening consisted of testing the
vehicle's fuel for lead content prior to entry into the program
(< 0.05 g/gal Pb), inspection for enlarged fuel inlet
restrictors, and a Plumbtesmo test of tailpipe deposits. Any
indication of previous use of leaded fuel was cause for
rejection. An exception was granted to the owner of vehicle
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#520 because the vehicle had been involved in a previous fuel
switching program. However, at the end of the previous
program, the vehicle's exhaust pipe, catalytic converter,
muffer and tailpipe had been replaced.
The vehicle types consisted of seven General Motors
vehicles, one Ford vehicle, one Chrysler vehicle, and one
Toyota vehicle. A list of the vehicles, their engine size,
induction type, VIN and engine family can be found in Table 1.
4.0 TEST DESCRIPTION
The vehicles were initially fueled with the low lead
gasoline. The vehicles accumulated mileage on public roads, in
normal driving, by the vehicle owners. Fuel was provided to
the vehicle owners without charge as an incentive. After each
refueling, the vehicles' tailpipes were tested using Plumbtesmo
brand lead detection paper.
Each vehicle was continuously refueled with the low lead
fuel until tailpipe lead deposits were detected in the tailpipe
at four consecutive fill-ups or until three months after the
start of 0.1 gram/gal fuel use, whichever occurred first. If
lead deposits were detected with lead detection paper after
four consecutive fill-ups, the vehicle was switched to unleaded
gasoline for the remainder of the three-month testing period.
After all testing was completed, the misfueled catalyst,
oxygen sensor, tailpipe, and spark plugs were replaced and the
lead poisoned parts shipped to EPA for possible further
analysis.
5.0 TEST PROCEDURE
In this study, the Plumbtesmo tests were conducted
outside, on warm vehicles (tailpipe was not so hot that it
could not be touched), and during the period from May to
October.
The test procedure was as follows:
The inside of the tailpipe was degreased by spraying
acetone onto it. The acetone was allowed to evaporate and
the excess solvent or soot was not wiped away.
The Plumbtesmo paper was then cut in half and moistened
with three drops of distilled water. The moistened paper
was pressed against the inside side surface of the
tailpipe and held there for one minute by the individual
conducting the test. After one minute, the test paper was
removed and judged as to whether a pink color was
present. This indicated a positive presence of lead.
-2-
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If the test was positive, a confirmatory test was
performed on the same spot in the tailpipe. If the test
was negative, i.e.,a color change was not observed, the
tailpipe was wiped out and degeased with acetone. The
test was then performed again at the same location
If the second test at the same spot was negative, the
tailpipe was again degreased and the test was performed on
the bottom of the inside tailpipe surface. If after the
three tests, no positive result could be determined, an
overall "negative" result was recorded. If any test in
any spot produced a reaction, a "positive" result was
recorded.
6.0 RESULTS
The lead detection paper results are shown in Tables 2-4.
For all vehicles a Plumbtesmo failure occurred at or prior to
the sixth tank of low lead fuel. For all but one vehicle, a
1984 Chevrolet Cavalier, the first failure occurred at or prior
to the fourth tank. Three GM vehicles experienced a Plumbtesmo
failure after only one tank of the leaded fuel.
The number of unleaded tanks that a particular vehicle
received varied from two to twenty-five. For some vehicles,
the presence of lead as detected by a positive Plumbtesmo
reaction never disappeared; while on other vehicles, the
positive Plumbtesmo vanished after just one tank of unleaded
fuel. Consequently, no definite conclusions regarding the
disappearance of lead deposits on tailpipes from unleaded gas
usage can be made. However, the disappearance of a positive
Plumbtesmo reading occurred on most vehicles after four tanks
of unleaded fuel use.
During the course of the test program several problems
occurred. For instance, difficulties in blending the second
batch of low lead fuel caused unscheduled unleaded fuel usage
in vehicles 512, 513, 517, and 520. Similarly, vehicle 516 was
filled twice away from the laboratory with unleaded fuel.
Vehicles 511, 512, 515 and 517 were "topped off" before a trip,
but did not receive Plumbtesmo tests at those points.
Vehicle 517 had cold start driveability problems near the
end of the program. Replacement of the oxygen sensor and spark
plugs at the end of the program cured the complaint. Also, the
front converter on vehicle 518 melted down and partially
plugged the rear converter. The owner had noticed a
deterioration in driveability which was eliminated following
replacement of the converter, plugs and sensor at the end of
the program.
One concern when using Plumbtesmo paper was that large
amounts of deposited lead would be removed from the tailpipe
-3-
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during repeated Plumbtesmo tests. This question was resolved
by removing the tailpipe from the vehicle and testing an
internal portion of it at the end of the testing program. The
results of testing an internal portion of the tailpipe were no
different than those performed at the normal outlet.
Plumbtesmo tests were performed on oxygen sensors and
spark plugs from the vehicles after they completed the final
fueling with unleaded gasoline. The number of unleaded tanks
that a particular vehicle received varied from two to
twenty-five. The Plumbtesmo paper, in all cases, gave a bold
pink reaction indicating the presence of lead on the oxygen
sensor. Plumbtesmo tests performed at the vehicles' spark plug
electrodes, after the final fueling with unleaded gasoline,
showed the presence of lead on most of the spark plugs from all
of the vehicles. One spark plug from vehicle 511 tested
negative for lead and the other plugs from that vehicle
produced only faint pink reactions. The negative Plumbtesmo
reaction correlates well with the relatively high amount of
unleaded fuel (180 gallons) which vehicle 511 consumed prior to
the final Plumbtesmo test. This result indicates that the
presence of lead due to misfueling may disappear from spark
plugs after the vehicle has operated on unleaded fuel for more
than 6000 miles. In a similar misfueling study done by General
Motors (ref 1.), it was found that the degree of Plumbtesmo
reaction decreased similarly.
-4-
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References
Mclntyre, Barbara R. and Faix, Louis J., "Leed Detection
in Catalytic Emission Systems and-Effects on Emissions.
SAE Paper 860488, February 1986.
Michael, R. Bruce, "Misfueling Emissions of Three-way
Catalyst Vehicles." SAE Paper 841354, October 1984.
"Misfueling with Reduced Lead Content," Prepared by
Automotive Testing Laboratories for EPA under Contract
68-03-3230, September, 1986.
-5-
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Table 1
Test Vehicle Information Table
VEH ^VEHICLE DESCRIPTION ENGINE FAMILY
511 1983 Olds Cutlass D4G3.8V2NEA3
512 1983 Olds Cutlass D4G3.8V2NEA3
513 1984 Chev. Cavalier E1G2.0V5XAJ5
514 1983 Chev. Citation D1G2.8V2NNA9
515 1985 Buick Skyhawk F1G2.0V5XAG1
516 1983 Ford Thunderbird DFM5.OV5HLFB
517 1983 Buick Regal D4G3.8V2NEA3
518 1983 Dodge Diplomat DCR3.7V1HAS3
519 1982 Buick Skylark C2G2.5V5TPG5
520 1981 Toyota Celica BTY2.4V2EF6
VIN NUMBER
1G3AR47A7DM550973A
1G3AR47A4DM5543514
1G1AD69PXEJ1092641
1G1AXCBX7DT101244
1G4JT27P8FK479237
1FABP46F3DHI42704
1G4AM69A1DH813308
2B3BG46H5DR104747
1G4AB37R6CT106181
JT2RA44L3B0026720
-6-
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Table 2
VEHICLE PLUWBTESMO TEST RESULTS
VEHICLE
511 512
513
514
515
516
517
518
519 520
Incoming
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
TANK
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
F
F
P
F
F
F
F*
F
F
P
F
P
P
P
F
F
F
P
P
F
P
P
P
P
P
P
P
P
P
P
P
P
P =
F =
1 =
F
P
P
P
P
F
1
p**
p**
F
P
P
P
P
P
P
P
-
-
-
-
P*
P
P
P
P
F*
F*
F
F
F*
P
P
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Pass or
Fail or
Vehicle
* p
P
P
F
F
* F
* F*
F
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
negative
positive
received
F
F
F
F
F
F*
F
P
F
P
P
P
P
i
±
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
P
P
P
F
F
F
P
2
2
P
P
P
-
-
-
-
-
-
-
-
Plumbtesmo
Plumbtesrao
only a half
P
P
P
F
1
p* *
F
F
F
P
P
P
P
-
-
-
-
-
-
-
-
-
-
results
results
a tank
P
P
F
F
F
F*
F
F
F
F
F
F
F
F
F
F
P
P
P
P
F
-
-
-
-
-
-
-
-
-
-
-
of
P
P
P
F'
F
F
F
F*
P
P
P
-
-
-
-
-
-
-
-
-
P
P
P
F
F
p* *
F*
F
P
F
P
P
P
P
P
-
-
-
-
-
-
-
-
-
-
2 =
*
* * =
of leaded fuel.
Vehicle was filled with unleaded on road.
No test was performed.
Vehicle was permanently switched to
unleaded fuel.
Vehicle was temporarily switched to
unleaded fuel due to fuel blending
problems.
-7-
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Table 3
Tailpipe PI umbtesnio
Vehicle
511
512
513
514
515
516
517
518
519
520
Engine C
MYJJ Vehicle Size
83 Olds Cutlass 3.8L
83 Olds Cutlass 3.8L
84 Chevy Cavalier 2.0L
83 Chevy Citation 2.8L
85 Buick Skyhawk 2.0L
83 Ford T-Bird 5.0L
83 Buick Regal 3.8L
83 Dodge Diplomat 3.7L
82 Buick Skylark 2.5L
81 Toyota Celica 2.4L
Vehicle MYR Vehicle
511 83 Olds Cutlass
512 83 Olds Cutlass
513 84 Chevy Cavalier
514 83 Chevy Citation
515 85 Buick Skyhawk
516 83 Ford T-Bird
517 83 Buick Regal
518 83 Dodge Diplomat
519 82 Buick Skylark
520 81 Toyota Cel ica
Catalyst
Type
OX/3CL
OX/3CL
3CL
OX/3CL
3CL
OX/3CL
OX/3CL
OX/3CL
3CL
3CL
Engine
3.8L
3.8L
2.0L
2.8L
2.0L
5.0L
3.8t
3.7L
2.5L
2.4L
Leaded
Tanks Gal s Miles
7 99.7 1748
15 215.4 4395
7 72.4 1781
7 91.2 1613
6 69.9 1979
11 155.4 2236
12 155.7 3087
6 80.0 1511
8 90.4 1779
6 79.4 1715
Table 4
Catalyst
Tvpe Tanks
OX/3CL 25
OX/3CL 2
3CL 6
OX/3CL 2
3CL 8
OX/3CL 2
OX/3CI 1
OX/3CL 16
3CL 4
3CL 10
Total
grams
of Lead
10.0
21.5
7.2
9.1
7.0
15.5
15.6
8.0
9.0
7.9
1st Pb
Failure
1
1
6
4
1
4
4
3
4
4
1st Pb
Failure Plumbtesmo Presence of Le,
(gal s) Oxygen Sensor Spark Plugs
14.2 Yes yes«««
14.4
62.1
52.1
11.7
56.5
51.9
40.0
45.2
52.9
Yes yes
Yes yes
Yes yes
Yes yes
Yes yes
Yes yes
Yes yes
Yes yes
Yes yes
Tailpipe Plunibtesmo
after unleaded fuel use
Unl eaded
Gals
347.0
29.6
61.9
24.3
93.4
24.9
14.5
207.7
42.5
142.3
Miles
6441
607
1473
440
2653
568
:soo
3502
892
3109
Last Pb
Failure
13
-
1
-
4
-
1
II
1
4
Last Pb
Failure
(gal s) Comments
180.4
*
10.3
_ *
46.7
_ * *
14.5
142.8
10.6
56.9
I
CO
I
Comments:
* During the misfueling portion of this test, the car was temporarily put on unleaded fuel.
The vehicle's fuel was re-filled on the road. See -text.
*** Lead was not detected on every spark plug of Lhis vehicle.
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