Re: Failed Emission Test - WHY?


<lukus2005@xxxxxxxxx> wrote in message
news:1174137648.448182.303370@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I just bought a 1994 Camry LE 3.0L and it failed the Ontario Vehicle
Emissions Inspection to my surprise.

The engine runs super smooth and all the leaks at the flanges were
fixed. Here are the results of the tests...

ASM2525 TEST
HC ppm..... limit: 57...... reading: 89..... FAIL
CO %........ limt: 0.32.... reading: 0.31.. pass
NO ppm..... limit: 421.... reading: 9...... pass
RPM: 1683..... valid
Dilution: 15.0.. valid

CURB IDLE TEST
HC ppm..... limit: 200.... reading: 30..... pass
CO %........ limt: 1.00.... reading: 0.01.. pass
NO ppm..... N/A.... reading: N/A
RPM: 705...... valid
Dilution: 14.9.. valid

Gas Cap Pressure Test: pass

The brochure they provided me says the problem could be one of the
following:
- vacuum leaks
- ignition system malfunction
- faulty computerized engine management system and/or oxygen sensor
- faulty air injection system
- internal engine problem
- failed catalytic converter

Now I'm told by the guy who checked out the car for me before buying
it, he thinks that it could be the oxygen sensor (but the Camry
apparently has 2 of those and which one to change is a (guess). He
doesn't think it's a vacuum problem or a computer/engine problem given
how smooth it runs. He's really leaning on the oxygen sensors.

The car may have been sitting for about 4 months before I drove it
about 75 miles to get tested. Now I'm told that because it has sat
for a while, I should fill it using Super gasoline and one of them
"Garanteed to pass" engine cleaner you put in the gas.

I even had someone suggest I put Coleman Camping Stove fuel in my
gas. Apparently it burns hotter than regular gas and thus does a good
job at cleaning the engine and catalytic converter. Anyone ever heard
of that trick?

Reading other threads, most seem to point towards either the EGR valve
or the oxygen sensors. I'm hesitant to start replacing parts in the
hope I replace the right part... could end up costing me a fortune if
i take that route. I need your help please.


It looks like the car passed everything except the Hydrocarbons (HC) test
above idle.

From this article about emissions testing:
http://www.aa1car.com/library/tr1196.htm

"Hydrocarbon failures mean unburned gasoline is passing through the engine
and entering the exhaust. The three most common causes include ignition
misfire, lean misfire and low compression (typically a burned exhaust
valve). Ignition misfire can be caused by worn or fouled spark plugs, bad
plug wires or a weak coil. Lean misfire results where there is too much air
and not enough fuel, so check for vacuum leaks, dirty injectors or a fuel
delivery problem. In addition to these, hydrocarbon failures can also be
caused by oil burning due to worn valve guides, valve guide seals and/or
rings."

As viperkiller mentioned, do not try any home brews like Coleman gas, etc.
Premium fuel will not help.

What may help is a bottle of fuel injector cleaner like Chevron Techron or
the stuff that Toyota dealers sell, although I doubt if it would make much
of a difference.

If you replace ignition parts, I recomend using OEM ignition parts to
increase your chances of success.

You an try cleaning the Mass Air Flow Meter located at the outlet of the air
filter housing with carb cleaner.

Regarding O2 sensors, the #1 sensors on the exhaust manifold control fuel
mixture, the #2 sensor by the catalytic convert monitor the converter.
Check both #1 sensors operation before replacing them so that they are not
replaced needlessly.
--

Ray O
(correct punctuation to reply)


--

Ray O
(correct punctuation to reply)



.

Relevant Pages

  • Re: Help. replaced dead battery, now engine starts but wont run.
    ... Ignition module is a possibility also or bad ign switch. ... The systems can be checked easier while the engine is not running or not ... Hmm...ok, dead battery. ... - checked fuel pumps, both run when ignition turned on and stop when ...
    (rec.autos.makers.vw.watercooled)
  • Re: Running out of Ideas, HELP
    ... The problem is non-starting, it just cranks, thats it. ... it could be in the ignition system or the fuel system. ... resistance of the pick up coilreplace the main engine ...
    (alt.autos.toyota)
  • Re: Running out of Ideas, HELP
    ... The problem is non-starting, it just cranks, thats it. ... it could be in the ignition system or the fuel system. ... resistance of the pick up coilreplace the main engine ...
    (alt.autos.toyota)
  • Re: Switch mode regulators - PWM, VFM, etc.
    ... > there could be a big kablouie and the engine went to shreds. ... procedure is to shut off the fuel and keep the ignition on. ... the engine is off, as long as it is rotating, oil is being pumped ...
    (sci.electronics.design)
  • Re: Any hope? ST (Itlaian) ST .25 ? (ATTN: LONG)
    ... Super Tigre carburetor adjustment procedure ... The Super Tigre carburetor has two needle valves for adjusting fuel ... left of the carburetor throat (as viewed from rear of engine). ...
    (rec.models.rc.air)