Failed smog with high HC and CO

[mtseymourguy]

High HC(489 ppm) and CO(9.99%). Nitrogen Oxide was the best in 5 years.
(similar results on both driving and idle test). They said the CO was the worst they have seen.


I recently installed a new catlytic converter. Had my distributor out and timed it to about 25(stock is 20) before top dead center because it idled better at that position. no check engine codes.

[BAM]

not an expert but sounds like an air intake problem or maybe to much fuel

[notanexpert]

This indicates either way too rich mixture or incomplete combustion for some reason. I'm afraid unless you fix that asap your new catalytic converter may be toast if it is not toast already. Unburned fuel (which is what HC is) absolutely poisons catalytic converters.
Maybe a bad Oxygen sensor is causing the engine to run in open loop which would cause the rich condition?

[mtseymourguy]

my car computer by design ignores the O2 sensor during idle so it cant be the o2 sensor since my problem occurs in idle and driving test. unless the idle test can be contaminated by driving test somehow.

I suspect it is my timing but I'm only off stock by 5 degrees.

looking a the graph of HC and CO, they are both flat . I wonder if a working
O2 sensor would show ups and downs.

I tested the O2 sensor with my car computer and the light never came on indicating that the car stays rich and never goes lean. I assume though that the computer relies on the O2 sensor to decide if things are lean or rich.

[Pete_Coach]

High HC are always indicative of incomplete combustion and could be anything from bad timing, ignition system failing, poor plugs and failing injectors plus a multitude of combination.
CO tells you about the fuel mixture. Poor O2 sensors, lean condition, vacuum leaks, MAF sensors can all be part of the cause of this reading.
You need to fix theses problems in steps and do tests in between to see if you are going in the right direction.
Oh and adjusting your idle by using the distributor and changing the timing is waaayyy wrong.

[maniacshopper]

definitely seen this happen before.

is this car your daily driver? old gas or new gas? it can make a difference.
Other than that, get an OBDII reader like innova 1003, it can access your car's computer. It can tell you if you have a problem with a high CO and HC readings.
It's an air fuel mixture issue, either running too lean or too rich. Typically shows up when too lean, the O2 sensor will say spray more, there's only so much air the intake will flow, unless you have FAI.

Hookup OBD2 reader, and adjust the air fuel mixture, usually near your throttle body next to your intake butterfly.

[mtseymourguy]

Oh and adjusting your idle by using the distributor and changing the timing is waaayyy wrong.

I guess i explained it wrong. I took the distributor out and then when I put it back in the timing was way off so I had to time it. It seem to idle better with timing advanced 5 degrees. I assumed this was because the car was older or that I have my idle set much higher than spec to prevent stalling at stop signs. People are saying that changing stock idle can create emission problems. I hope this is enough to explain my horrendous aircare results.

[Pete_Coach]

I guess i explained it wrong. I took the distributor out and then when I put it back in the timing was way off so I had to time it. It seem to idle better with timing advanced 5 degrees. I assumed this was because the car was older or that I have my idle set much higher than spec to prevent stalling at stop signs. People are saying that changing stock idle can create emission problems. I hope this is enough to explain my horrendous aircare results.

Still wrong. If the ignition spark occurs too soon it can push against a piston traveling up as it is compressing the fuel/air mixture. This causes detonation, lost power, much higher combustion temperatures, backfires, and early internal engine part failures. If the spark occurs too late, the ignition of your fuel mixture occurs after the piston is traveling back down the cylinder. This is wasted energy, unburned fuel, high emissions, and lost power.
Your vehicles computer determines the fuel and ignition based on lots of parameters and if you mess with the distributor, the computer is starting off with wrong input signals and affects the total timing curve of the ignition system.

[maniacshopper]

can believe we're still discussing this. It's the air fuel mixture. we've had this on our cars, prior to driveclean. Do what I've said, then adjust the air fuel mixture. There's a flat headed screw on the throttle body, you adjust that. Try half a turn at a time, every 1 minute, make the adjustment, until it goes away. Make sure you know what the position, ie. how many turns it is till it stops. It will work. We even made the mistake of replacing the O2 sensor, bloody expensive.

[Pete_Coach]

can believe we're still discussing this. It's the air fuel mixture. we've had this on our cars, prior to driveclean. Do what I've said, then adjust the air fuel mixture. There's a flat headed screw on the throttle body, you adjust that. Try half a turn at a time, every 1 minute, make the adjustment, until it goes away. Make sure you know what the position, ie. how many turns it is till it stops. It will work. We even made the mistake of replacing the O2 sensor, bloody expensive.

What is your problem?
Can a discussion not continue after you have said your piece? No one is disputing you but, there may be some that might not think you are the definitive vehicle guru.
There is a chance (albeit a slim one) that someone else might have the right or alternative answer too.

[mtseymourguy]

Still wrong. If the ignition spark occurs too soon it can push against a piston traveling up as it is compressing the fuel/air mixture. This causes detonation, lost power, much higher combustion temperatures, backfires, and early internal engine part failures. If the spark occurs too late, the ignition of your fuel mixture occurs after the piston is traveling back down the cylinder. This is wasted energy, unburned fuel, high emissions, and lost power.
Your vehicles computer determines the fuel and ignition based on lots of parameters and if you mess with the distributor, the computer is starting off with wrong input signals and affects the total timing curve of the ignition system.

My ecu is obd1 but I think I might be able to figure this out. At the moment, the ecu diagnostics are saying the O2 sensor is not working. The light should blink to indicate alteration between lean and rich. I'll play with the timing to see if ecu likes it better.

This is the fourth year in a row that I have failed with high HC and CO: bad computer, leaking injectors, and disconnected AIV. This is the first year that I dont have code for too much fuel and this is the first year the computer diagnostics say the O2 sensor is not working.

[mtseymourguy]

My o2 sensor was unplugged. I'm getting blinking light now indcating optimal mix. Mystified why I fail at idle because o2 sensor is ignored during idle as far as I know.

[ES_Revenge]

I suspect it is my timing but I'm only off stock by 5 degrees.

I took the distributor out and then when I put it back in the timing was way off so I had to time it. It seem to idle better with timing advanced 5 degrees. I assumed this was because the car was older or that I have my idle set much higher than spec to prevent stalling at stop signs.

This is the fourth year in a row that I have failed with high HC and CO: bad computer, leaking injectors, and disconnected AIV. This is the first year that I dont have code for too much fuel and this is the first year the computer diagnostics say the O2 sensor is not working.

I dunno but reading this thread kinda makes my head hurt.

I mean you have all these things running out of spec--advanced timing, high idle, etc.--that seem to be being done on purpose and then when you see the result of such things (high emissions) you're asking why you have the high emissions? "LOL what?"

Are you even running higher than normal octane after advancing the timing 5 degrees? Because that would definitely be a good idea. (Probably won't do anything about these emissions problems but it's not a exactly a great for the engine to to permanently advance timing and not change the fuel.)

Are the injectors still leaking? Or were the bad one(s) previously replaced. If they are still leaking well there's just another problem to add to the others.

It's just a little puzzling to me. Change a bunch of stuff so the engine is running completely differently than it was designed and then scratch your head when the emissions problems pop up? Not only that, do the same thing year after year? Not trying to be rude at all, I'm just honestly not understanding the "logic" in this whole operation LOL. I'm glad this foolery is not really possible on modern cars...

[mtseymourguy]

I dunno but reading this thread kinda makes my head hurt.

I mean you have all these things running out of spec--advanced timing, high idle, etc.--that seem to be being done on purpose and then when you see the result of such things (high emissions) you're asking why you have the high emissions? "LOL what?"

Are you even running higher than normal octane after advancing the timing 5 degrees? Because that would definitely be a good idea. (Probably won't do anything about these emissions problems but it's not a exactly a great for the engine to to permanently advance timing and not change the fuel.)

Are the injectors still leaking? Or were the bad one(s) previously replaced. If they are still leaking well there's just another problem to add to the others.

It's just a little puzzling to me. Change a bunch of stuff so the engine is running completely differently than it was designed and then scratch your head when the emissions problems pop up? Not only that, do the same thing year after year? Not trying to be rude at all, I'm just honestly not understanding the "logic" in this whole operation LOL. I'm glad this foolery is not really possible on modern cars...

All the problems from previous years were fixed. As I said, the O2 sensor was unplugged. The connection was wrapped up in tape so I didnt see that. I've always passed with my idle higher than factory and mechanics have left the idle at that level. Only thing that changed this year was the timing and obviously the o2 sensor was unplugged.

[mtseymourguy]

I took it back through aircare with the o2 sensor plugged in this time. Still failed but obviously did better. The graph is totally different with o2 sensor working so someone should have been able to point that out.

I cant get to base timing because car stall at base timing. I'm getting an obd 1 consult plug so i can read timing , etc directly from computer.

Aircare is nothing but a tax on the poor.