Contour Enthusiasts Group Archives Forums General Troubleshooting P0430 maybe fixed without replacing cat?

About 2 years ago, I had the dealer replace the bank 1/rear cat because of a P0420 code. This was at 79,950 miles. Yes, 50 miles prior to the emissions warranty expiration!

About 6 months ago, at 90,000 miles, I had the CEL come on and it was a P0430 code, bank 2/front cat. I changed the plugs and wires and cleared the code. The code did not come back until recently.

When I was driving to PA last week, the CEL came on and I had the codes scanned when I arrived. The code was a P1151, o2 sensor lean/no switch (bank 2/front). I replaced that O2 sensor last night, cleared the codes, and went for a test-drive to see if the problem was fixed.

When I got home, I rescanned the codes and got a pending P0430 code. I went for another test drive and the pending code became a hard code, turning the CEL on. I cleared the code, and drove back home.

Tonight, coming home, the CEL came back on, P0430 again.

I did a little research on this forum and found that Big Jim said that he had gotten these codes intermittently, but they went away, and he thought some reasons why is that he cleaned the throttle body/intake/combustion chambers on a regular basis and kept the ignition system in good shape.(This is one reason why I thought to change the plugs/wires when I got the P0430 the first time).

I had never really cleaned the throttle body/intake/combustion chambers on this Contour, so I decided that would be a good start.

I took off the air duct, and started the engine. It died right after starting. My old '95 Contour had no problem starting when the air duct was off. I thought maybe the MAF should be unplugged. I unplugged it and it started right up without dying.

Then I got a can of B12 Chemtool Carb and Choke Cleaner and sprayed it in while revving the engine up. I probably used about half a can. It made the exhaust STINK. I am sure some of it was going through the engine unburned. I made sure the secondaries opened up a few times while I was spraying it in. I didn't spray it all in at once, I sprayed on-and-off for a few seconds each time, to avoid overheating the cats.

After I was done I cleared the codes (P0430 and a code from the MAF being unplugged), and went for a test drive.

When I got home rescanned the codes.

"ALL READYNESS TESTS COMPLETE", said the scantool. Then, without displaying any codes, it went to menu. (If there are any codes, pending or hard, it displays them after it says whether the readyness tests are complete)

Could it be? It completed all readyness tests without detecting a problem with the cat? I double checked and went to the data->codes->pending display, and it said "NO CODES AVAILABLE".

I guess I'll find out in the next few days if the cat still has problems, but this is really encouraging. I wonder what effect the B12 Chemtool had on the cat that made it start working better?

I had 430 and 420 codes as well I cleaned the tb as well but with tb cleaner and didnt run the car at the time. however my codes returned...the stealership said it would cost $1600 to change the cats. Another shop told me they can cut it out and replace it without removing the manifolds. I have been trying to get a solution to my code problem for a while. Have you done anything special inorder to pass the emmissions?

Nope, I haven't taken it it for emissions check YET, but it's due shortly.

I think two of the main reasons that cleaning the throttle body may have fixed the cat (the code hasn't come back and I drove it 3 times today) is because I did it:

1)With the engine running

2)With B12 Chemtool Carb and Choke cleaner

The reason I think doing it with the engine running helped the cat is that some of the cleaner got into the cat and either cleaned it up by solvent action or by heating the cat up, or both. The cleaner also cleaned the intake valves and combustion chambers on it's way through the engine.

Much more than just the throttle body gets cleaned when you do it with the engine running.

The reason I think that using B12 Chemtool Carb and Choke cleaner helped the cat is that it has some pretty heavy-duty solvents (especially compared to throttle-body cleaners):

Toulene, Methanol, Acetone, Mixed Xylenes, Methy Ethyl Ketone, Butoxyethanol and Isopropanol

This stuff is so powerful it will dissolve paint!

Some people on this forum have suggested that the use of such heavy-duty solvents like those found in carb cleaner may damage the teflon coating in the throttle body, but I look at it this way:

1)The teflon coating doesn't do much.

2)There's no evidence that carb cleaner damages it.

3)If I'm on the line to spend several hundred dollars on a new cat, I don't care about the teflon coating.

Based on my experience here, this what I would do if I were in your situation:

1)Use about 1/2 of a 16 ounce can of B12 Chemtool Carb and Choke Cleaner to clean the throttle body with the engine running. Rev the engine as you clean it. Spray it in until the engine starts to slow down, then stop spraying until the engine speeds up. Repeat this process. There's no need to use a brush to clean the throttle body when using B12 Chemtool.

2)Replace both upstream oxygen sensors, to provide better fuel mixture control so the cat can operate more efficiently. Oxygen sensors do degrade over time and if they have over about 60,000 miles on them, replacing them will help. They start to degrade long before the check engine light ever comes on.

Don't worry about the downstream oxygen sensors, they RARELY (if ever) cause a P0420/P0430 code so save the money for the upstream sensors, the ones that really matter.

3)Replace the plugs/wires if they haven't been replaced in a while.

4)Put Chevron Techron Concentrate fuel injector cleaner into the gas.

Brian,

While I know you are excited about the very short-term results you have seen, it would be prudent to wait for a much longer period of time before prescribing this as a fix.

Personally, I am not optimistic that you have fixed anything and that the symptoms are most likely to appear in short order.

Here is a Ford TSB that is intended to provided guidance to dealership technicians in diagnosing concerns with HO2 sensors and cats: http://www.thedieselstop.com/faq/9497faq/tsb/tsb/files/010907.pdf

Pay particular attention to the section on pages 8-10 that describe how the cat efficiency monotoring works. If your scan tool is capable of displaying the front vs. rear O2 sensor outputs, you will be able to see what effect the cat is having on the oxygen level in the exhaust. With this real-time data, you will be able to see the actual performace of the cat and will be able to see if the performance is changing as you drive the car a few more miles.

Again, I would urge caution and more time before trying this on another car with 0420/0430 codes.

Steve

If you got to replace that cat on your car you gotta do what my buddy did. Tear the thing off your car, go to the hardware some 2.25 pipe or whatever inch yours take, and weld it on there.

Doubt I'll have to do anything, it should pass emissions with no problem since I replaced both upstream O2 sensors, it's got new plugs/wires, I cleaned the throttle body/intake/combustion chambers, and there is still no P0430 code.

I've been driving it in a way that should ensure the catalyst monitor runs more often.

Here is the post from Big Jim that makes me think what I did may have fixed the cat.

Let me quote the relevant portion:

Quote:

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With all that said, I have had that code set on my car from time to time and the cat seems to have restored itself. I have not had it on for at least a year. I have scanned the oxygen sensors and the cat monitor oxygen sensors and they are switching as expected, fast in front and very slow in rear. The cat has not been replaced. It may help that I clean the throttle body, intake manifold, combustion chambers, and injectors often and keep the ignition system and air filter is exception condition.

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http://www.asashop.org/autoinc/july97/techtotech.htm

Quote:

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My other converter test requires extreme caution. On a questionable converter, I will cause one cylinder to misfire by disconnecting and grounding a spark plug wire. While running the engine at 2,000 rpm, a helper monitors the converter shell temperature. A good converter will heat up very quickly, usually 800 degrees Fahrenheit on the outside in less than two minutes. The 800-degree outside temperature usually indicates the core has reached 1200 degrees, and that's plenty. Too hot for too long is going to melt the converter substrate. This test has two functions - first, it confirms the converter is working, and secondly, it "cleans" the converter of contaminating coatings. The converter can become coated with sulfur and/or carbon, usually from older drivers that drive short trips at low speeds. We have some elderly customers who never achieve closed loop. Every year we have to change their oil to remove the fuel in the oil and light up their converter to pass emissions. Many techs advise the highway burn out for the converter, but we have found the misfire trial by fire a better solution. Be careful!

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My emissions test results as of 2/9/04, with 97394 miles:

15MPH
HC ppm limit 81, reading 9, PASS
CO% limit 0.45, reading 0.03, PASS
NO ppm limit 647, reading 2, PASS
Dilution 15.2 PASS

25MPH
HC ppm limit 78, reading 13, PASS
CO% limit 0.43, reading 0.04, PASS
NO ppm limit 585, reading 2, PASS
Dilution 15.2 PASS

Emissions test results as of 11/08/01, with 71184 miles. You will note that the test results, with the exception of the 15MPH CO%, are noticeably worse than those above:

15MPH
HC ppm limit 81, reading 35, PASS
CO% limit 0.45, reading 0, PASS
NO ppm limit 647, reading 103, PASS
Dilution 14.80 PASS

25MPH
HC ppm limit 78, reading 47, PASS
CO% limit 0.43, reading .01, PASS
NO ppm limit 585, reading 418, PASS
Dilution 14.81 PASS

Emissions test results as of 05/25/2001, with 71178 miles. It failed this test, I believe it sat parked between 05/25/2001 and 11/08/01 (this is prior to my ownership of this car):

15MPH
HC ppm limit 81, reading 3, PASS
CO% limit 0.45, reading 0, PASS
NO ppm limit 647, reading 69, PASS
Dilution 14.60 PASS

25MPH
HC ppm limit 78, reading 5, PASS
CO% limit 0.43, reading 0, PASS
NO ppm limit 585, reading 1003, FAIL
Dilution 14.50 PASS

Emissions test results as of 05/24/1999, with 68416 miles (being driven only about 3000 miles in 2 years could have caused NO ppm limit failure above, carbon build-up due to short-trip usage):

15MPH
HC ppm limit 81, reading 3, PASS
CO% limit 0.45, reading .09, PASS
NO ppm limit 647, reading 8, PASS
Dilution 14.79 PASS

25MPH
HC ppm limit 78, reading 7, PASS
CO% limit 0.43, reading .05, PASS
NO ppm limit 585, reading 5, PASS
Dilution 14.75 PASS

Emissions test results as of 05/21/1998, with 43743 miles. This is the first time the vehicle had ever been tested, note that all readings except HC PPM are higher than the test I had done today:

15MPH
HC ppm limit 81, reading 5, PASS
CO% limit 0.45, reading .07, PASS
NO ppm limit 647, reading 5, PASS
Dilution 15.17 PASS

25MPH
HC ppm limit 78, reading 11, PASS
CO% limit 0.43, reading .15, PASS
NO ppm limit 585, reading 6, PASS
Dilution 15.25 PASS

My '96 Contour now has 98,080 miles with no reccurance of P0430 code.