Hello everyone. I am brand new to the site so if my post is in the wrong place I apologize.

I am desperate for help regarding my 1994 Honda Accord EX 2.2 Liter Engine with 200+,000 miles not passing SMOG.

I was able to get a 7 page smog diagnosis report outlying the problem, however I am female and do not understand a word. The only thing I interpret is a lot of $$$$. I can't afford to put thousands into this car just to pass smog, but am willing to spend a few hundred if the problem is fairly simple.

Here is what the emission results are: High NOx, CO and HC at 15/25mph.

I don't know where to start with this car. The report talks about a defective catalytic converter but states that CA law says all emission faults must be tested and repaired before a new cat can be considered. That sounds expensive to me.

Please if anyone can help me with some suggestions on how to fix this mess, and not get ripped off, I would appreciate all your thoughts. I have been without a car for almost 9 months now and need to do something. I can make the report available or any other info needed. Please understand that I don't know what I should post as far as numbers are concerned.

Thank You
Jennnifer

 

Hey Jen, sorry to hear about failing your smog. Take a picture of your results and post them up. and if you have a moment, do a search..there are plenty of suggestions here to help you out.

 

OK, here is the ASM Emission Test Results
RPM %CO2 02 HC (PPM) CO% NO (PPM)
TEST MEAS MEAS MEAS MAX AVE MEAS MAX AVE MEAS MAX AVE MEAS
15MPH 1698 14.4 0.8 61 29 52 0.51 0.09 0.71 490 169 82 FAIL
25MPH 2603 15.2 0.2 36 17 18 0.49 0.08 0.00 730 139 1164 FAIL

Visual Inspection PASS Functional Check PASS Emissions FAIL

Then there are 3 columns with a bunch of tests ECS? and it says PASS next to each one.
The Odometer is: 248210 VIN: JHMCD5561RC045051 2.2 Liter engine.

Thanks for the help! What should I search for smog problems?

 

CO is non existent at the 25MPH test, and NOx is high. The car is running lean at cruise rpm.

I would suspect the EGR system is partially clogged and needs to be cleaned.
In the Accord FAQ at the top of the page there is the procedure on how to clean it.

 

Thanks Mad Mike...I'm afraid that task is way beyond my ability's. Here's the report they sent me.


SMOGSMART VIR REPORT – 1994 HONDA ACCORD 2.2 LITER ENGINE
SmogSmart VIR Report #658327

Your vehicle’s emissions results: High NOx, CO, and HC at 15/25mph.

Quick Diagnosis: Ultimately you will need a smog repair station to verify this hands-on... but after a complete fuel and ignition system inspection either no faults have been found, or faults found and repaired yet vehicle still fails test, consideration should be given to a defective Catalytic Converter. However it is very important to insure that in fact all other emissions systems are inspected prior to the CAT’s replacement.

Shop Diagnosis: A smog check repair station will first have to find out if your vehicle is in proper fuel control. The diagnosis for this fault should begin with the inspection of the fuel injection “feedback” system. This includes insuring the oxygen sensor is working properly, your vehicle's emissions computer is receiving the signals from the oxygen sensor, the computer is computing the data properly and sending the correct signals to the fuel injectors to either increase or decrease fuel delivery to the combustion chambers.

The feed back test will utilize a 5-gas analyzer (usually a smog machine) and propane. The smog technician should introduce propane to the intake system and insure the oxygen sensor is reading this introduction as an increase in CO, and ordering the computer to decrease fuel delivery at the instant propane is added to the system. This test should be done after the engine has sufficiently warmed up and while it is running at idle. If no change in fuel delivery is seen we know we have a feedback problem. Then the diagnosis should turn to which part of the feedback system is defective. Using a voltmeter the technician should observe the voltage output of the oxygen sensor as propane is added. Voltage should increase. If there is no increase we have a defective O2 sensor. The sensor should be replaced and the test started over. If voltage increase is present at the sensor output the technician needs to insure voltage increase is also present at the computer input terminal. If voltage is present at the terminal as well next the technician must insure the computer output terminal to the fuel injectors are lowering “injector pulse rates”.

The additional sensors which should be inspected for proper operation (and which also play a significant role in determining air/fuel ratio) are the Engine Coolant Temperature (ECT) sensor and the Mass Air Flow (MAF) sensor. If the coolant temperature sensor is not operating properly (not sending the correct voltage signal to the Engine Control Module) the ECM will not be able to properly calculate how much fuel to deliver to the combustion chambers. When the engine is cold the ECM is programmed to deliver a richer fuel mixture (more fuel). As the engine warms up, the ECM will lean out the mixture. Insuring the ECT is sending the correct voltage to the ECM is important for correct air/fuel ratio (optimum is 14:7). The MAF sensor measures the amount of air entering the intake manifold. This sensor must send accurate information to the ECM as well, in order for the ECM to calculate exactly how much fuel to add to the air entering the combustion chambers.

At the end of the feedback test it will be know whether your vehicle is in proper fuel control, and if not, whether the problem is electronic or mechanical. The technician can further diagnose the fault. If the fault is determined to be mechanical, the locations which need to be inspected are any and all points of "fuel entry"... such as and most predominantly the Fuel Injectors. It is not uncommon to a stuck "closed" or "sticking" fuel injector to cause low CO. One other mechanical fuel related concern is that of a malfunctioning "fuel pressure valve". This valve during normal operation will return all unused fuel to the fuel tank.

What is CO: CO stands for Carbon Monoxide. It is a by-product of incomplete combustion, more then often related to the presentation of too much fuel to the combustion chambers. The spark created at the sparkplug can only burn a small amount of fuel, the fuel it cannot burn is sent out the tailpipe and will normally contain high levels of partially burned fuel(CO) and un-burned fuel(HC). In a "Rich Fuel" condition diagnosis would begin with inspecting all possible mechanical faults which could cause excessive fuel to enter the combustion chambers. This diagnosis would include inspecting your vehicle for high fuel pressure, intake vacuum leaks, air restrictions and/or leaking fuel injectors. A dirty air filter may restrict ample air from entering the combustion chambers. The lack of air will create a rich fuel condition and result in high CO.

Defective Emissions Component (sensor, solenoid, ECU) - Your vehicle's engine has several emissions sensors which send vital engine information to the emissions computer as well, such as the TPS (Throttle Position Sensor), ECT (Engine Coolant Temperature Sensor) and the MAP or MAS (Vacuum/Pressure Sensor). These components should be inspected individually after a feedback test insuring proper oxygen sensor operation first.

Defective EVAP System - The EVAP system is designed to introduce gas vapors into the combustion chambers. These gases are just as combustible as the fuel in your gas tank. If they are not routed into the combustion chamber, the vapors build up within your engine's fuel system and escape through a vent into the atmosphere. In order to fix this problem auto manufactures have designed the EVAP system to make use of the vapor. Gas tank vapors are collected by the EVAP canister and stored for use during cold starts and acceleration. A defective EVAP system may be delivering vapors when not needed or at all times. The fault may be due to a defective solenoid, and/or mechanical fault.

What causes High HC: Hydrocarbon is basically raw fuel, otherwise known as gasoline. The main reasons vehicles fail for high HC is defective spark delivery. During the combustion process any number of engine conditions can cause emissions failures. Out of the three systems your engine relies on to produce combustion (air intake, fuel delivery, and spark control), the spark system has the components which require replacement most often. Sparkplugs and spark wires are constantly exposed to high temperatures and high voltages. You must insure your engine's ignition system is functioning properly, by inspecting all the sparkplugs and their wires. If any of the plugs look worn out or have excessive carbon build-up replace them immediately. You may use any brand of product designed to work in your vehicle. The distributor cap should also be inspected for cracks or excessive carbon deposits. If it appears that the cap may be faulty, you will need to replace it. More then likely you will see an instant performance increase once these corrections are made.

What does HC have to do with the High CO: There is a condition called the "Rich Misfire" your vehicle might be suffering from. This condition is created, when for any reason, the combustion chambers receive too much fuel, causing the fuel that is delivered to burn improperly and leave behind high levels of raw fuel(HC) and partially burned fuel(CO). Vehicles producing high HC for fuel management reasons usually begin producing normal HC levels once the fuel problems are corrected.

However for those vehicles suffering from high HC not related to fuel management, should have the engine ignition system closely inspected.

What is NOx: NOx stands for Nitrous Oxide. NOx is a chemical created when an engine's combustion chamber temperatures rise above 2500F. CO is a by-product of incomplete combustion caused by either too much or not enough fuel being sent to the combustion chambers. As we now know, fuel distribution to the engine's combustion chambers is controlled by the vehicle's computer and carburetor, and air/fuel mixture must be preciously controlled to produce the least emissions.

When the fuel injectors do not present enough fuel to the combustion chambers, the chamber temperatures increase resulting in high NOx emissions. When the fuel injectors present too much fuel, this causes a decrease in NOx emissions, but an increase in not thoroughly burned fuel (CO) as well. The excessive fuel being sent will keep the combustion chamber cool, but raise CO levels.

As noted the component responsible for letting the computer know how much fuel is in the exhaust system at any given moment, is the Oxygen Sensor. If for any reason the 02 sensor does not send accurate information to the computer or it is "lazy" in sending the correct signals, the fuel delivery program can be altered. The computer may then present either too much or not enough fuel to the combustion chambers and therefore cause an emission failure.

In this particular case we have both high CO and high NOx. Normally these emissions contradict each other, which leads us to believe the EGR valve which also controls NOx might be defective. Read on...

The EGR Valve - EGR stands for exhaust gas recirculation. The EGR valve is responsible for re-circulating a small amount of exhaust gas back into the combustion chamber. This is done to cool down the chamber temperature by producing an inert gas along with the regular fuel mixture. Nitrous Oxides emissions are formed when engine chamber temperatures rise above 2500* F. Keeping the chamber cool reduces NOx emission.
The EGR valve should be inspected to insure its proper operation. A working valve should be able to open its passage using manifold vacuum. Manifold vacuum is created during the engine's intake cycle. The high demand for air during this cycle creates a vacuum within the engine's intake manifold. This vacuum is then used to control several important functions within the vehicle, including controlling the EGR valve. Some vehicles even rely on this vacuum to control their heating and air-conditioning components.

The EGR system is prone to collecting carbon build-up. Since the EGR valve pulls exhaust gasses from your exhaust and introduces them back into your engine's intake air over time it will become clogged or stuck open/closed from the carbon deposits. It is possible to clean the EGR valve if you remove it from your vehicle and either spray it out or let it sit in regular gasoline.

More NOx Faults - Bad engine cooling and high mileage may cause NOx failures as well.

Bad Engine Cooling - If your engine's cooling system is not working efficiently, chances are there is an excessive amount of NOx being created. Remember NOx (Nitrous Oxides) is created only when an engine's combustion chamber temperatures reach over 2500F. A bad cooling system will create NOx. For this reason you want to make sure your vehicle's temperature gauge is always normal and that your cooling system is working properly. If your vehicle has an overheating problem, be sure to perform the necessary repairs prior to your next test.

High Cylinder Compression - Carbon build-up within your engine's combustion chambers will cause increased engine temperature and high NOx. Carbon build-up normally develops in an engine's combustion chambers over some period of time. High increase in carbon build-up causes increased cylinder compression, which causes high temperatures, which result in high NOx emissions. Keep in mind this problem is usually seen in vehicles with over 200,000 miles. The solution to this problem is called an Engine DeCarbonizing.

It usually costs around two labor hours at a smog repair station. It will remove a good amount of carbon of your engine's piston heads and valves. This will increase combustion space, lower compression and lower NOx.

Defective CAT - The final emissions component to be suspected after all else fails by California Law. The Bureau of Automotive Repairs actually disallows replacement of the CAT until all other emissions components have been inspected and no faults found, or found and repaired. The Catalytic Converter, commonly referred to as the CAT is a component designed to continue the combustion process within itself and emit a more thoroughly burned and less harmful emission containing exhaust. It is normally placed between your engine's exhaust port and your car's muffler. It allows the engine exhaust to pass through while it reduces all emissions. A good CAT should dramatically reduce HC, CO and NOx. The CAT is a catalyst, it plays a very small part on how well your engine runs and it only begins working after slightly rich exhaust has exited the engine's combustion chambers.

The most accurate way to find out if your vehicle CAT is working efficiently is by using an exhaust gas analyzer. Unfortunately this tool is fairly expensive and intended for use by professionals. You might need to visit a local smog station and have the smog technician inspect the CAT with their smog machine. They will do "snap test" to check the CAT's efficiency in reducing emissions during an immediate increase in fuel.

Obvious symptoms of a bad CAT however could be any of the following:

a. loss of power over 15-25 mph (CAT is plugged up and restricting exhaust flow)

b. very strong exhaust smell on a vehicle that runs great(engine running efficiently, but CAT not completing the burning process)

c. Loud rattle being heard from inside the CAT (CAT substrate broken up).

Final Comment: We hope this report is helpful to you. There will be a few steps involved in finding out the root cause for your vehicle's failure/s. The emissions system/s responsible for causing high CO, NOx & HC will have to be individually diagnosed, and step-by-step eliminated as faults. Please Remember: California law only allows only a vehicle's owner or a State Certified Smog Repair station conduct smog inspections and smog repairs We highly recommend you search our database of SmogTips State Certified Smog Repairs stations. SmogTips Certified Stations are pre-screened for quality repairs, fast friendly service, and reasonable prices.

SMOGTIPS SMOGSMART VIR REPORTS - Save Money. Smog Smart. SmogTips.com - "California's Leading Smog Check Support Group" - 1-877-SMOG-TIPS


From: jenwhe@live.com [mailto:jenwhe@live.com]
Sent: Tuesday, August 21, 2012 10:21 AM
To: VIRSupport1@smogtips.com
Subject: Online Smog Check Diagnosis


Smog Check Vehicle Inspection Report (VIR)

Contact Information



Vehicle Information

Model Year: 1994 Make: Honda Model: Accord
License: 3FLZ163 State: CA VIN: JHMCD5561RC045051
Engine Size: 2.2 Type: Passenger Transmission: Manual
GVWR: N/A Test Weight: 3250 lbs. Cylinders: 4
Odometer: 248210 Certification: CA VLT Record No.: 25666
Fuel Type: Gasoline Exhaust: Single Inspection Reason: HEP

Overall Test Results

Comprehensive Visual Inspection: Pass Functional Check: Pass Emissions Test: Fail

Emission Control Systems Visual Inspection/Functional Check Results

PASS EGR (Visual) PASS EGR (Functional) PASS Spark Controls
PASS PCV PASS Thermostatic Air Cleaner PASS Fuel Evaporative Controls
PASS Catalytic Converter PASS Air Injection PASS System Malfunction Light
PASS Fuel Cap Integrity Test PASS Ignition Timing: PASS Oxygen Sensor

ASM Emission Test Results

%CO2 %O2 HC(PPM) CO(%) NO (PPM)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS MAX AVE MEAS Results
15 MPH 1698 14.4 0.8 61 29 52 0.51 0.09 0.71 490 169 82 FAIL
25 MPH 2603 15.2 0.2 36 17 18 0.49 0.08 0.00 730 139 1164 FAIL


MAX=Maximum Allowable Emissions AVE=Average Emissions For Passing Vehicles
MEAS=Amount Measured

Smog Check Station Information

Station:

 

That is an overly wordy 'report'. It does not point you to what your issue is. I would recommend NOT using any shops they recommend, if they did.
Seems more like they are trying to place fear into a customer.

Here is an emissions pdf that is more user friendly.
Toyota emissions pdf
This could be a simple misprint, or someone was not watching their spell checker.
NOx is a generic representation of Nitric Oxide(NO) and/or Nitrogen Dioxide(NO2)
Nitrous Oxide(N2O) is more commonly known as laughing gas. Often called 'NAAAAWS' by the street racer crowd. This is different from NOx.

 

CO2 and O2 levels look good meaning your air to fuel ratio is good. Looks like your NO and CO levels are too high. My first guess based on the age of the vehicle would be your EGR system and then your catalytic converter.

Here are the things to check for high CO:
http://www.smogtips.com/failed-high-...onoxide-CO.cfm
For high NO:
http://www.smogtips.com/failed-high-...rous-oxide.cfm

 

Thank you so much for all the input, I have had absolutely no idea where a good starting point would be. Now thanks to you guys, I feel like this might be fixable. So one last question I have; should I be worried about the fuel injectors or does it have nothing to do with my current issues?

 

Anyone live in CA and want to make some x-mas money??

 

Not really.
With a catalyst these numbers can be skewed to look acceptable but do indicate a slight issue.
CO2 is slightly higher than normal which for these accords it's usually 14.4.
The 15.2 shows there is an increase of CO2 produced. If there is a misfire, HC and O2 will be combusted again inside the catalyst combine and creating more CO2 than normal output.
Along with the non existant CO levels, the left over O is combining with N in the catalyst and that is increasing NOx.

This is why it is best to look at CO and O2. These will give a better understanding of what is happening in the primary/secondary combustion process.
Do you mean 'low'?
I'm of the belief there is a lean misfire due to a clogged EGR system.
During EGR application the timing is advanced more than would be needed for non EGR diluted combustion. If the EGR system is non fully functional, but the timing is still advanced one will have a lean misfire due to excessive advanced timing. This 'excessive' advanced timing is needed to aid in proper primary combustion when the mixture is diluted with spent exhaust gases.

This is also why one cannot just simply remove an EGR system from a vehicle without changing the timing advance tables in the ECU.

 

Doubtful it has anything to do with the injectors. If you think they are clogged or sticking, Then stick a pit can of SeaFoam into the tank at your next fill up. OReilly has it.

Your car has 200,000 miles. The EGR system just eventually becomes obstructed with soot and carbon. Honda even recognized this as an issue and made it simpler to clean by engineering a separate manifold for the EGR system on the 94-97 Accords. Scroll down to the fourth picture in this link94-97 Accord EGR Port Cleaning.

 

Am I right in saying that on a F23A1 manifold there is a totally different EGR arrangement, and the exhaust gas goes straight into the plenum and not into the individual runners? I have been thinking about switching to the F23A1 manifold on my 94.

 

What would a girl do without forums like this? I appreciate all the input and expertise. So to re-cap this to verify I'm understanding this correctly, the consensus is that my Honda-rodi's problem is likely an EGR failure and should be changed. In addition to the EGR replacement the timing should be checked to be sure it is not advanced creating a lean misfire? Ok I think I got it.

What's your feeling on this feedback test the report says needs to be done? I'm thinking after the EGR is replaced that I'll take it to one of those "pass or don't pay" smog stations and if it still fails then ask about the feedback test. Hopefully with the help of a service manual I can attempt to do this myself. I should video-tape the process, it would be comical!!

Dumb question, but if I were to put a new engine in would that cure my problems? I mean I realize the catalytic converter is in the muffler and could also be contributing to the problem, but what about all the other gazillion parts? This might be the better option??? Any advice??

 

These egr valves are very strong and don't usually go bad. Shops love replacing them because they make money on the part with little work done. You can usually clean them out and return them to workable condition. Fortunately for you, your car is fairly easy to clean out the egr ports as there is just a plate that you need to remove and clean versus other accord where you have to take numerous things off and/or need to drill out plugs. It's sort of a dirty job so if you wanted to get your hands dirty you can use this video as a guide. You will also need to get an egr valve gasket from a parts store and take off the egr valve and spray some carbon cleaner to get all the "gunk" out from the egr valve.

If you have any hands-on guys available they can probably do the job too. You can also check around and see if a shop will do an egr system cleaning. After doing this if you can you can go back to that smog place for free, if they offer a free retest, if not then just have a place do a "pre-test" for like $20 or so. If it still fails, then you can have a muffler shop put a new cat on. You should check around for the cheapest shop.

https://www.youtube.com/watch?v=d8N-SE047VY