Need a few less hydrocarbons....

[Joe Bob]

Anybody have FIRST HAND experience with a fuel additive to reduce HC? I've done the AF adjustment, valves, new pulgs cap(s) and rotors.....

I'm at 124 at idle..... need to be under 120....

[Joe Bob]

"I" have heard that a quart of Naptha in three gallons of gas is good for 20-30 ppm.....but that's what "I" have heard....

[emcon5]

Posted on Usenet usenet rec.autos.misc a while back, credited to "William R. Watt"

Begin big-ass cut/paste:-----------------


The following guide is intended to help the owner of a car which has
failed an emissions test to understand what may be wrong with the car.
Since I am not a mechanic it may contain emissions :-) or errors. If so
I'd appreciate comments as it is intended for emailing to peope who post
emissions queries in the rec.autos. newsgroups.

thanks.

====================================





Emission (smog) test problems.
==============================

What to look for when any of CO, HC, NOx too high.

CO: rich fuel mixture
HC: incomplete combustion
NOx: hot combustion and rich fuel mixture
CO, HC, and NOx: incomplete exhaust conversion

80%-85% of vehicles pass emissions tests.
an in-tune well-maintained vehicle should pass.
allowances are made for the age of the vehicle.
for the rest some details are provded below.

note that both CO and HC rise in the absence of O2 (oxygen) in
combustion and in exhaust, and that NOx rises in the abscence of
O2 at high combustion temperature. HC also rises when there is
too much O2 in combustion.

1. CO (carbon monoxide) too high.
---------------------------------

causes:

a) not enough air (oxygen) in air/fuel mixture to make carbon
dioxide (CO2) so get carbon monoxide (CO) instead (mixture too
rich). can be too little air or too much fuel in mixture.

b) not enough air (oxygen) in exhaust system to convert CO to CO2

c) faulty catalytic converter.

look for:

a) too little air - dirty air filter, stuck choke, plugged or
sticking PCV or EGR system, plugged carbuettor or injector air
passage

b) too much fuel - carburettor or fuel injection system supplying
too much fuel

c) too little air or too much fuel - engine control system -
vacuum hoses, sensors (eg exhaust oxygen, temperature, air flow),
computer, actuators (eg fuel metering solenoid, air metering
solenoids), wires and connections (control system voltages are so
low that small resistances from dirty or loose connections make a
big difference), the computer uses the input from the sensors to
send signals to the actuators to keep the air/fuel mixture at the
optimum for power, fuel efficiency, and low emissions.

d) too little air in exhaust system - restricted outside air feed
to converter (eg air pump or pulse air system - hoses, electrical
connections, valve, pump, drive belt, sensors)


2. HC (hydrocarbons, ie unburned fuel) too high.
------------------------------------------------

causes:

a) not enough oxygen in combustion to burn all the fuel, or too
much fuel (mixture too rich), so excess fuel blows out exhaust.

b) too much oxygen in combustion or too little fuel (mixture too
lean) for uninterrupted combustion (engine misses), so unburned
fuel blows out exhaust.

c) sparkplugs not firing properly to ignite air/fuel mixture
(ignition system), so unburned fuel blows out exhaust.

d) combustion chamber too cold for complete combustion, so
unburned fuel blows out exhaust.

e) combustion chamber hot spots preventing complete combustion,
so unburned fuel blows out exhaust.

f) not enough air (oxygen) in exhaust system to convert HC to H2O
and CO2.

g) faulty catalytic converter.

note that HC in exhaust can combine with S (sulphur) from fuel to
produce rotten egg smell.

look for:
---------

a) mixture too rich - see a,b,c in CO section above. note that if
HC is too high but CO is okay then the problem is not a rich
mixture.

b) too much oxygen in combustion - leaks of air (hoses, gaskets)
and routing of hoses into intake manifold, leaks in EGR and PCV
valves

c) too little fuel - dirt in fuel/filtre/tank/lines, leaks in
fuel lines or connections, weak fuel pump, - mechnical problems
in carburettor (dirty valves or passages or linkages, worn parts
or gaskets) or fuel injection system

d) too much air or too little fuel - computer not mixing air and
fuel properly (see c in CO section above)

d) ignition system - sparkplugs fouled (type of fouling may
indicate problem), poor contact or insulation in high voltage
ignition wires or in distributor (cap, rotor), poor contact in
coil wires, low voltage in charging system (alternator,
regulator), faulty transistorized ignition control module

e) combustion chamber too cold - sticking EGR valve or sitcking
cylinder exhaust valve or bad cylinder valve timming letting
"cooler" exhaust gas into the combustion chamber.

f) combustion chamber hot spots - bits of junk (dirt, carbon) or
nicked or burned metal parts glowing red hot in combustion
chamber and igniting air/fuel mixture (engine misses) - can use
chemical cleaner in combustion chamber or take engine out on the
highway or both to burn off junk - overhaul engine to remove
nicked or burned metal parts or hardened junk

g) too little air in exhaust system - see d in CO section above.


3. NOx (oxides of nitrogen) too high:
-------------------------------------

causes:

a) too much heat in combustion chamber - air contains about 78%
N2 (nitrogen gas) which becomes chemically unstable above 2500
def F and combines with O2 (oxygen, making up about 21% of air)
to form NO which, released into the atmosphere, forms NO2 which
in the presence of sunlight combines with HC (hydrocarbons) to
form smog. note that NOx only happens when engine is under load
(car at crusing speed on road or rollers).

b) too much CO in exhaust (CO enhances the conversion of NO to
NO2).


look for:

a) too much heat in combustion chamber - the EGR system or the
valve timing is used to bring exhaust gas back into the
combustion chamber to cool it off when the engine is hot under
load at cruising speed - check the EGR system valves, solenoids,
wiring, hoses - if the car does not have an EGR system check
valve timing - (engine cooling (water) and lubricating (oil)
systems may have some effect on combustion chamber temperature?)

b) computerized engine control system - adjusts engine operation
to minimize emissions (see c in CO section above).

----------------------------------------------------------------

sources:

"Automechanics" (Prentice-Hall, 1988)
"Import Car Manual 1983-1990" (Chilton, 1989)

[Joe Bob]

The P-car wrench says my cats are failing,,,,,they are relatively new,,,,arrgh...

[emcon5]

This is on the 3.6?

This is secondhand, but I have heard that you can unplug the electrical connection on one of your fuel injectors and run one cylinder as an air pump.

I don't know if this will give you a check engine light.

Just a thought.

Tom

[ischmitz]

So all the hard work last weekend did exactly NOTHING??!! to the results.

What did you do to the AFM. Leaning it out by backing out the adjustment screw?

Ingo

[cowtown]

Originally posted by emcon5
This is secondhand, but I have heard that you can unplug the electrical connection on one of your fuel injectors and run one cylinder as an air pump.

Interesting. Would the O2 sensor try to richen up the mix because of all the extra O2?

[Joe Bob]

Originally posted by emcon5
This is on the 3.6?

This is secondhand, but I have heard that you can unplug the electrical connection on one of your fuel injectors and run one cylinder as an air pump.

I don't know if this will give you a check engine light.

Just a thought.

Tom

I'm just trying to get the #s down....the readings out of the right muffler are higher than the left muff. This is what leads me to beleive the cats (new last year ) are failing....

I will go to the muff guy and see if he will stand behind them.....

It's called RXP. Try THIS site.

[sammyg2]

Ethanol will help more than naphthalene, but too much of a good thing is too much.
I figure about 5 to 7% ethanol by volume would be max. to try and get it to pass. If that don't do it you need to try and fool the O2 sensor into thinking it's running too rich.

[Joe Bob]

Sammy...where does one get Ethanol, especially if one does not work in a refinery....

[ischmitz]

Ethanol should be available at homeless depot.....

fooling the O2 sensor is harder to do. I would first try to disconnect one of the injector connectors and see if that gets you anywhere. Is it the side with the O2 sensor that gives worse results? If so you are lucky: The O2 sensor won't notice that the other bank has one bastard cylinder just pumping air.....

Ingo

[ruf-porsche]

Originally posted by mikez
Sammy...where does one get Ethanol, especially if one does not work in a refinery....

All the gas stations in Chicago has a blend of ethanol and gasoline. The blend is used to cut down on the pollution. Try checking to see if the gas stations in a large Urban area near you are also blending their gasoline with ethanol.

[campbellcj]

76 gasoline here has ethanol I believe; they stopped using MBTE a year or two ago

[ischmitz]

If you pee into your tank after a heavy night out that might do the trick, too......

ingo

[sammyg2]

Most auto parts stores carry fuel additives that are supposed to help you pass smog. They are mostly ethanol with some detergent additives.
Kind of expensive but it's only a one time use thingy.

[Joe Bob]

Ethanol is not a common product in hardware stores...as to using one cylinder on the opposite side as an O2 pump, that won't work as there is no cross over on the exhaust pipes....

[ischmitz]

Mike,

One bank is monitored by the O2 sensor in your setup. If you are lucky, it is the "dirty" bank. That way disconnecting one injector on the clean bank will make it even cleaner without the O2 sensor fighting the changed conditions. No need for a cross-over.

If your clean bank is the one that is monitored by the O2 sensor you will have to try if the dirty unmonitored bank cleans up enough by running on 2 fueled barrels or if disconnecting one barrel on the monitored dirty bank cleans that one up enou gh without the O2 sensor messing with the mixture.

ingo

[Joe Bob]

The bank with the 02 sensor is higher on the HC....BUT....is not the control of mixtures via the DME for ALL cylinders?

[john walker's workshop]

disable the fuel flow to one injector. that turns the cylinder into an airpump, and dramatically lowers emissions. on electric injectors, pull the electrical connector off. on CIS, substitute an injector with a brazed up tip, or plug the fuel distributor port to that injector. then you can pass the test and deal with the problem later.