failed CA emissions test :(

[vizvo]

Let's analyze the test results. Your CO is very low. That is good. And your O2 is low. That is good. Your CO and O2 numbers indicate that complete combustion is taking place. It looks to me like your problem is related to raw fuel in the exhaust stream. A bad float in the case of a carburetor, a misfire, or carbon build-up in the combustion chamber are possible culprits.

Carbon deposits in the combustion chamber act like a sponge and soak up HC on the intake stroke. This HC does not vaporize, and it is not burned. It is released unburned into the exhaust stream on the exhaust stroke. It would not be unusual to have an 18 year old car with considerable carbon build up inside the heads.

My first suggestion would be to clean the combustion chambers. Go to your GM dealer and buy a can of GM Top Engine Cleaner (part number 1050002). Read the directions on the can. Basically you dribble it into a manifold vacuum port while "idling" the engine at about 2000 RPM. It will create a lot of smoke. If you can't get hold of GM Top Engine Cleaner, try Sea Foam available from Advance Auto or other parts stores. Some folks have even used a pint or two of distilled water. Dribble it, don't pour. You don't want to damage your engine by hydro-locking it.

Your numbers are not that bad. Your mixture is good. I doubt that the problem is your O2 sensor. If anything your O2 and CO numbers look ever so slightly skewed to the lean side. You have a tired catalytic converter or raw fuel problem. Start by cleaning the combustion chambers.

And for the love of all that is good and holy, don't scrap this car. It would be a dang waste of a good car to send this vehicle to the crushers.

 

[m2200b]

Your rough idle is probably old gas if the car sat unused for awhile. The GM intake cleaner will help (as would techron) and don't run this car below 1/4 tank or you'll be adding blocked carb jets to its problems with old fuel varnish.

 

[GoldenRod]

m2200b,

You are right. I was assuming the poster had the car for at least two years.

 

[chas3]

i wouldnt add mmo to the tank the next time you go in for the test. it probably lowers octane.

due a couple WOT after you get the engine warm. that should help loosen up the rings and the blow out some carbon. really.

 

[m2200b]

I do like Vizvo guess on unburned gas passing through at idle that clears up at speed for your HCL gross polluter reading. Late 80's carbs are among the most complicated in the world. If the car sits they varnish up with old gas in them.


I would also recommend a pretest when you've done all you can afford to see whether you pass.
The only reason you want another fail is to have it and your receipts to get another dmv 2 month extrension and you can get that with just the recipts and a pretest or even just the receipts.

 

[teambeechstreet]

thanks vizvo and others! Well I finally got the o2 sensor out and since I already have the new one in hand, I guess I'm gonna throw it on. I'm also gonna try some of that SeaFoam stuff. Read a lot of good reviews on it around the net. I also have a new cat that should be arriving tomorrow.

 

[cousincletus]

I would run the fuel tank almost empty and put in about 4-5 bottles of alcohol from the drugstore. Have heard this works as the alcohol burns a lot cleaner than gas. Thank goodness we don't have emissions here in central VA (yet).

 

[brianl703]

Retarding the timing (below factory spec) might help.

 

[m2200b]

CA checks your timing in the test.

 

[brianl703]

VA doesn't.

 

[Winston]

I think Visvo has got the ticket. Carbon in the combustion chambers.

I would be wary of a $72 Cat.

How did you get the O2 sensor out?

 

[vizvo]

Hey teambeechstreet. I was thinking about your problem and tried to do a little research on your Colt's the emissions system. One area you failed to mention is the air injection system. Checking on a Alldata I was surprised to find that there are quite a few variations of air injection on that model: carb, fuel injected, and turbo charged fuel injected. And throw in California and Federal versions. They all seem to use some version of pulsed air so I assume you don't have a smog pump.

On the carb version, from the diagrams it appears to be a clean air feed from the air cleaner to a reed valve which feeds into the exhaust manifold ahead of the cat. The reed valve should open on negative exhaust pulses, sucking in fresh air from the air cleaner and directing it the exhaust stream.

If this reed valve were stuck open, it could mimic a stuck open EGR valve, particularly at low rpm. It wouldn't hurt to check the reed valve and see if it is operational. I don't know if you can clean them or have to replace them. I guess you don't have your old air cleaner, but you could still do a visual check inside the air cleaner housing and look for signs of carbon or exhaust residue where the air injection hose connects. A problem here could be the source of your rough idle.

On the other hand, if this valve were stuck closed or sluggish, you still might see elevated hydrocarbons because the cat is not getting enough air to function efficiently. Check and see what the cost of replacing the valve with a new one is. Since you are already buying a cat and an O2 sensor, it might not hurt to go ahead an replace the reed valve if in doubt.

Also be sure to check all the hoses in the air injection system. Verify that they are not plugged, cracked, or leaking. Come to think of it, did you check your EGR valve? That is another item that might be do for replacement. It that were stuck open you would have rough idle and other problems. Oh, and did you try to pull any trouble codes? I believe most Mopar vehicles from that era had a way to blink out the codes without a need for a scan tool.

By the way, I failed to call attention to your CO2 numbers my last post. They are excellent. The CO2 figures are used as an indicator of combustion efficiency. Yours are right on the money. Between 14% and 15% CO2 is top of the line. Combine them with your really good CO and O2 numbers, and it is clear to see the excess hydrocarbons are not a result of bad closed loop control or mixture or ignition or combustion problems. In fact, although I mentioned "misfire" in passing in my last post, this is obviously not the case because your O2 numbers are so low. Misfire shows up with greatly elevated O2 levels.

When running well, your car was known for really good fuel efficiency. I would expect that you should easily get over 30 MPG, maybe close to 40 MPG on the highway. Whatever it costs to fix, this car will reimburse you at the gas pump.

 

[teambeechstreet]

quote:

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Originally posted by Winston:
How did you get the O2 sensor out?

---

Warmed up the car to normal operating temp, found an o2 sensor 7/8" socket I had previously lost, and combined that with a breaker bar. **** thing finally came off!

quote:

---

Originally posted by vizvo:
Hey teambeechstreet. I was thinking about your problem and tried to do a little research on your Colt's the emissions system. One area you failed to mention is the air injection system. Checking on a Alldata I was surprised to find that there are quite a few variations of air injection on that model: carb, fuel injected, and turbo charged fuel injected. And throw in California and Federal versions. They all seem to use some version of pulsed air so I assume you don't have a smog pump.

On the carb version, from the diagrams it appears to be a clean air feed from the air cleaner to a reed valve which feeds into the exhaust manifold ahead of the cat. The reed valve should open on negative exhaust pulses, sucking in fresh air from the air cleaner and directing it the exhaust stream.

If this reed valve were stuck open, it could mimic a stuck open EGR valve, particularly at low rpm. It wouldn't hurt to check the reed valve and see if it is operational. I don't know if you can clean them or have to replace them. I guess you don't have your old air cleaner, but you could still do a visual check inside the air cleaner housing and look for signs of carbon or exhaust residue where the air injection hose connects. A problem here could be the source of your rough idle.

On the other hand, if this valve were stuck closed or sluggish, you still might see elevated hydrocarbons because the cat is not getting enough air to function efficiently. Check and see what the cost of replacing the valve with a new one is. Since you are already buying a cat and an O2 sensor, it might not hurt to go ahead an replace the reed valve if in doubt.

Also be sure to check all the hoses in the air injection system. Verify that they are not plugged, cracked, or leaking. Come to think of it, did you check your EGR valve? That is another item that might be do for replacement. It that were stuck open you would have rough idle and other problems. Oh, and did you try to pull any trouble codes? I believe most Mopar vehicles from that era had a way to blink out the codes without a need for a scan tool.

By the way, I failed to call attention to your CO2 numbers my last post. They are excellent. The CO2 figures are used as an indicator of combustion efficiency. Yours are right on the money. Between 14% and 15% CO2 is top of the line. Combine them with your really good CO and O2 numbers, and it is clear to see the excess hydrocarbons are not a result of bad closed loop control or mixture or ignition or combustion problems. In fact, although I mentioned "misfire" in passing in my last post, this is obviously not the case because your O2 numbers are so low. Misfire shows up with greatly elevated O2 levels.

When running well, your car was known for really good fuel efficiency. I would expect that you should easily get over 30 MPG, maybe close to 40 MPG on the highway. Whatever it costs to fix, this car will reimburse you at the gas pump.

---

thanks again for all the info vizvo. i really appreciate you taking the time to research and help me with my car. actually on my first post, i mentioned that it has a 1.5 carbed engine. unfortunately, I'm not as educated in engines as a lot of you, so I'm not actually sure what a reed valve is and where to purchase the right one. I did notice a pipe leading into the exhaust manifold just before the o2 sensor, but i cant follow where it leads to.

As for the EGR valve, I feel pretty dumb saying this, but I dont know what it looks like so I'm not able to locate it in the engine. I googled up some pics, but they all look different. I have the Haynes manual for the car, but the engine diagrams they have are from the 79-81 engines that look completely different.

I tweeked the idle adjustment just slightly yesterday and the idle is fine now, no rough running or the such. I also SeaFoamed the engine on Tuesday and dumped a can in the gas tank. Runs just a little smoother when accelerating from a dead stop. In the last two days, I've driven about 500 miles in the Colt (I do a lot of commuting) and have gotten about 33-34mpg.

I need to schedule a vacuum leak test soon, just havent had time with school and work. I'm hoping that will help with any cracked hoses. As for pulling trouble codes, where could I go to do so for an older vehicle like this?

Again, I completely appreciate your time and help.

 

[teambeechstreet]

ok well i located the reed valve. took it off and shot some air through it with an air tank/pump, but couldnt hear anything. sprayed some SeaFoam in there, let it sit for 5 mins, then dumped out the SeaFoam. Sprayed air through it again and I could hear the valve opening and air coming through the exhaust side. guess the SeaFoam cleaned it out a bit! wonder if itll help any? thanks again Vizvo. now I gotta find the EGR valve...

 

[m2200b]

Does autozone have your model or another one like it or mitsubishi in its online repair models so you can locate the egr valve
and scrape the carbon off it. Look at your exhaust manifold above the 02 sensor and it ought to tie into it. Looks like a 4 inch metal spinning top piped into your exhaust.

 

[teambeechstreet]

quote:

---

Originally posted by m2200b:
Does autozone have your model or another one like it or mitsubishi in its online repair models so you can locate the egr valve
and scrape the carbon off it. Look at your exhaust manifold above the 02 sensor and it ought to tie into it. Looks like a 4 inch metal spinning top piped into your exhaust.

---

checked autozone and they dont have an online repair model.

the only metal pipe tieing into the exhaust manifold is the one that leads to what I thought was the "reed valve" which I removed to clean out with SeaFoam.

Here are some pics. the first one is of the exhaust manifold and I circled the metal pipe that connects into it. The 2nd pic is of where the pipe (i put a green line on it) leads to from the exhaust manifold to what I thought was the reed valve (which I circled) which I removed and cleaned with SeaFoam. Is that actually the EGR valve?

thanks guys

 

[vizvo]

Yep, that picture is the reed valve (not the EGR). If you cleaned it and checked it with air, then it might be OK.

For the EGR location, Check under your hood for an emissions vacuum hose diagram. It should be a white piece of paper with black writing and diagrams printed on it, pasted somewhere under the hood area. It probably will have the EGR labeled, and you can figure out where it's at by tracing the vacuum hoses. If you can't find it, go to an auto parts store and ask them to open a box with the EGR valve for your car. Or at least show you a picture of one. I think your EGR might be connected very close to the base of the carb (not 100% sure).

But if you think your idle is OK, then don't worry about your EGR. It mostly affects NOX emissions, and for some reason it doesn't look like your emissions report covered NOX. Or did you forget to post that part of the report?

I'd be leery of adjusting the carb because you could make things worse for yourself if you start fiddling with it. By the way, that picture with your O2 sensor in it, what is that white stuff on the manifold? Is your exhaust manifold cracked? Oh, and I'm not certain, but I think your car is the same as a Mitsubishi Mirage. So information for that vehicle might be useful to you.

 

[teambeechstreet]

quote:

---

Originally posted by vizvo:
Yep, that picture is the reed valve (not the EGR). If you cleaned it and checked it with air, then it might be OK.

For the EGR location, Check under your hood for an emissions vacuum hose diagram. It should be a white piece of paper with black writing and diagrams printed on it, pasted somewhere under the hood area. It probably will have the EGR labeled, and you can figure out where it's at by tracing the vacuum hoses. If you can't find it, go to an auto parts store and ask them to open a box with the EGR valve for your car. Or at least show you a picture of one. I think your EGR might be connected very close to the base of the carb (not 100% sure).

But if you think your idle is OK, then don't worry about your EGR. It mostly affects NOX emissions, and for some reason it doesn't look like your emissions report covered NOX. Or did you forget to post that part of the report?

I'd be leery of adjusting the carb because you could make things worse for yourself if you start fiddling with it. By the way, that picture with your O2 sensor in it, what is that white stuff on the manifold? Is your exhaust manifold cracked? Oh, and I'm not certain, but I think your car is the same as a Mitsubishi Mirage. So information for that vehicle might be useful to you.

---

yeah, the exhaust manifold is cracked. i bought some exhaust sealer stuff but it does not look like it worked too well. gonna try something else. Yeah, the car is the same as a Mirage, but unfortunately there is no information on any Mirages before 1990

thanks again for your help

 

[vizvo]

You better get that exhaust manifold fixed before intalling your new catalytic converter. You could remove the exhaust manifold and bring it to a reputable welding shop for repair. Or you could try to find a replacement at the junk yard. You will also need an exhaust manifold gasket.

I know that this news might seem like a mountain of work piling on, but it really is the best long term solution. You could try to slip by emissions with the manifold as it is, and then re-evaluate your situation if it fails again.

Cast iron is hard to weld correctly because the welding will cause more cracks if the welder doesn't know what he is doing. Cast iron should be preheated to 700° F, and welded with a nickle based rod, and peened as the weld cools. Some gypsy welder might not know that. My guess is that it will cost something in the neighborhood of $50 to repair.

There is also a website called car-part.com where you can search online for replacement parts from wrecking yards. Probably $75 to $100.

The problem with a cracked exhaust manifold upstream of the O2 sensor is that it will cause the O2 sensor to give crazy results. That alone can cause emissions problems. It will also upset the backpressure and cause problems for the pulse air injection.

 

[m2200b]

I'd replace it with a junkyard manifold.
You may have to use a local locater as your car is not the standard tercel, civic that easy to pick and pull.

The sealer works ok on minor cracks and might be worth a try on the smog test but that is the entire manifold.