FaLKoN240

1994 Accord Wagon

I'm smogging the car because I'm trading it. This is keeping me from trading. Please help.

The car passed smog the first time with barely any maintenance done to it.

Recently failed for high CO. Just barely.

I recently changed the sparkplugs and the o2 sensor.

Car gets 20MPG average (quite annoying)

Yesterday I did the fast idle repair and cleaned the ICV as well. Didn't really change anything. :-/

0go-part

IS the air filter dirty?
Try cleaning out your EGR valve

MAD_MIKE

High CO indicates a rich running condition.

'Bay Area, CA', you have the 5 gas roller test. Post all the numbers.

FaLKoN240

It passes everything else. I'm getting .4% I can only roll a maximum of .3%

I just cleaned the air filter and did another test. Fail again.

My friend is a smog tech and recommends o2 sensor and if that doesn't work a new cat is in order. I'd prefer not to put another $200 into the car.

I will try the egr tomorrow

MAD_MIKE

IOW, post the numbers so we can all see what the gas analyzer is reading. Just because one gas is barely failing doesn't mean its just one thing.

Help us help you.

FaLKoN240

For sure ill post up a screen shot of the sheet tomorrow. Thanks for all your help!!!

FaLKoN240

BUMP pic of my smog sheet.

MAD_MIKE

I don't believe your car needs a new Catalyst, more like a tuneup.

CO2 is usually ~14.4 on the F22 cars from the various postings those whom have passed.
O2 should not be '0' this indicates more fuel than air.
HC is high, this indicate an incomplete burn.
CO is on the high side, indicative of a rich running issue.

If the engine has not received a tuneup in some time I would have that done. Verify base timing is correctly set, and use NTK brand plug wires, plugs and Denso, Delco or NTK O2 sensor. Change the oil if it is due as well.

Being an EX verify that there is no exhaust leak at or between the head>manifold>downtube>O2 senor pipe>catalyst. A false air signal would make the ECU think the engine is running lean and dump more fuel into the engine.

With the tuneup don't fret if your NOx raised up more, this is indicative of a more complete/efficient combustion.

FaLKoN240

The car has been recently tuned up. I think I'm going to buy a new O2 sensor and coolant temp sensor.

I don't hear an exhaust leak but...

I changed the plugs again today (after recently changing them)
and Sea foamed it. When I seafoamed it, I noticed a lot of smoke (exhaust) coming from the engine bay as well. Would that be coming from an exhaust leak?

Even after that, tried to get it to pass again.

No change.

COs still too high.

MAD_MIKE

Most likely. Trace it down. I use Sea foam for tracing exhaust leaks, hell'uve a lot easier than looking or listening for a leak, especially on a turbo car.

FaLKoN240

Car is going into the shop for new exhaust gaskets today or tomorrow.

Hopefully this fixes the problem! Fingers crossed!

FaLKoN240

So after $120 paying someone to change all the exhaust gaskets, the car is quieter and the pick up and idle are a little better.

Still failed smog CO still too high.

So, today I bit the bullet and paid $185 for a new cat to get welded in.

The welder told me it was the OG cat that came with the car.

FaLKoN240

Failed again this morning, but in a completely opposite way.

Now it's running too lean.



Previous test:

MAD_MIKE

Do you happen to have this test? In post #13 it appears to be the same printout as in post #7.
OOMPF. I wish you hadn't done that.
Output was off by such a miniscule amount that it seemed to be easily tuneable. What brand O2 are you using? Bosch and other beer can style O2S are inherently lazy.

Basing it off the test prior to exhaust gasket work it seems to have just been running a bit rich.

The problem with a new catalyst is that it can often cover up a problem.

Now your NOx is what is failing you.
So what?
The '95 EX is still pimping its OG catalyst 270K+ miles and it works fine.
Did the exhaust shop show you that the catalyst was dead with an infrared laser gun?

No.
Both O2 and CO are now nil, and HC is low. The NOx is what is causing the failure.

Is your NOx high due to the new catalyst that needs a bit of time to charge up? Or is there a fault in your ignition or EGR system?

Read this PDF http://www.autoshop101.com/forms/h56.pdf page 12 has examples I was thinking of may be the issue with your car.

It would be best that you provide what has been done to the car. What parts have been replaced with what brands, what is the base timing set to, and what is the fuel pressure?

It would be really helpful if you could post up the test numbers after the exhaust gasket replacement.

FaLKoN240

No, I don't have this test, just the two that I took pics of. My smog dudes are cool and just let me do test runs to see if my car is even close to the numbers. We were confident it would pass after a new cat was installed.

APW International AP4-156 O2 Oxygen Sensor

I changed the O2 out of curiosity to see if I could get rid of my 20mpg situation. I think this was the initial mistake I made. I should've changed the exhaust gaskets first.

After changing the O2 and failing, I cleaned all the HICV and FICV valves and throttle body.

Next I changed the plugs.

Then the exhaust gaskets.

And finally the cat.

I most recently in an attempt to pass smog cleaned the EGR by removing it from the block, opening and closing the diaphragm and drowning the valve along with the port in carb cleaner.

The car runs the best it has ever run, but today the nox ppm would not go below 600 unless we blipped the throttle to trick the ecu to run rich for a bit.

Smog tech thinks I have a shitty O2 sensor, or I have a cracked exhaust manifold.

So tired of this.

FaLKoN240

Just bought this O2 sensor.

http://www.ebay.com/itm/DENSO-234-42...item27cba32e1f

joe94wag

Hey Falkon - did you ever get to the bottom of your smog issues with the accord?

MAD_MIKE

Considering that he never followed through, didn't listen, and it's been two years since he has logged on. I'm going to go with no.

joe94wag

Hey - I posted my 5 gas sheet, but I don't see it here. Will do again. Since failing I replaced plugs, air filter, changed oil, and added seafoam to crankcase and gas.

MAD_MIKE

Running a bit on the rich side. This will not increase HCs, but it will reduce NOx.

Check for excessive fuel pressure/faulty FPR/restricted fuel return line.

Leaking fuel injectors/FPR.

Malfunctioning EVAP system.

Excessive fuel in oil.

PCV valve or hose clogged.

Incorrect inputs to ECM causing closed loop to rich.
Check MAP, TPS, Thermo sensor, and O2 sensors for faulty operation.

joe94wag

Thanks Mike. I posted this separately and got a response from Texas Honda who didn't mention any of these things, except a possible O2 sensor. He suggested air filter/air blockage.

PAHonda said "Inspect the distributor cap and rotor for signs of wear".

I'm not sure how to diagnose or repair any of the things you mentioned, and I would rather not start replacing parts unless I know they're bad.

MAD_MIKE

Most chain stores offer a tool 'rental' which is just a deposit down and then the deposit is returned after use.
Attach a fuel pressure gauge to the test port on the fuel rail and monitor fuel pressure.
This can aid in diagnosing a faulty FPR(fuel pressure regulator) or fuel filter.
Not as easy to do, but can be done. Pull the fuel rail off and pull the injectors out, if there is carbon build up on the spray tip, or the injector tip is leaking fuel/dribbling it may not be shutting off fuel completely when 'off'. This will add to excessive emissions/fuel consumption.
Check vacuum hoses for damage/missing connections. A service manual would be best to have to trace down every line.
This is pretty simple, pull out the dip stick, what color is the oil? If it is dark it needs changing. Take a whiff of it, if it smells like gas, you have gas in your oil.
Center of your valve cover there is a plastic valve that has a hose that goes to the intake manifold. Pull that valve out(PCV valve) and see if it rattles. If not it may be stuck or clogged. Clean it with carb cleaner if it is gummed up, get it to rattle again. With the engine on you should be able to pull the valve off without it affecting engine running, place your finger over the end of the valve, it should suck on your finger and you should feel the valve move.
MAP and TPS can be back probed and checked for linear voltage change with a voltmeter. Should be a smooth transition.
Thermo sensor should be with-in expected resistance parameters.
O2 sensor you would want to back probe and monitor for switching. If it is stuck on one voltage or switches slowly or limited voltage change then the O2 may have become lazy.

As for spark plugs/rotor/cap/wires.
Check the cap and rotor for corrosion/damage/wear. Terminals under the cap sometimes get a corrosion or buildup of dried booger looking crud. Gently scraping that off will improve idle quality. Verify the rotor is not worn from arcing/corrosion. Verify spark plug wires are within reistance figures. Honda(Sumitomo) wires are best, NGK Blues second best, everything else can be hit/miss mostly due to ill fitting spark plug boots that do not seal or pop off. Check spark plugs for wear and correct gap.

joe94wag

THANKS SO MUCH FOR THE AWESOME INFO, MIKE!

Changed the oil, plugs, filters, and threw half a can of seafoam into the gas. Passed smog!

I will get to those other things you mentioned to get the best mpg.

I do have one more question:

Do I need to "jump" ECM connector (under glove box) to set ignition timing?

Thanks again! All the best - joe

NerfGunner420

yes you do. jump it. and set timing. and you are done!

MAD_MIKE

Yeop. It is always best to follow standard operating procedure and jump the connector to verify that base timing is correct.