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.pdfPay 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
Originally posted by projectSHO89:
Again, I would urge caution and more time before trying this on another car with 0420/0430 codes.
If nothing else, what I have suggested doing WILL help to reduce exhaust emissions, and a vehicle that is getting P0420/P0430 codes needs all the help it can get.
That, combined with the fact that 1996-2000 vehicles can still pass an emissions check with as many as two readyness tests not complete (for those states that actually do an OBD-II scan), should help the odds of passing an emissions check.
Viewed as a last-ditch effort to avoid the expense of replacing a cat, this makes sense, unless you think it would cause damage to the vehicle.
I will report the results of my forthcoming emissions inspection as well as reporting if the code comes back or not after I have put some more mileage on it.
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:
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.
http://www.asashop.org/autoinc/july97/techtotech.htm Quote:
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!
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.
I manually cleaned my intake manifolds and injectors. My lean codes and my misfire codes are gone, but I still have a PO420. I have 3 weeks left until I have to go retest at the emissions site. I failed in February based off of my OBDII. New O2 Sensor(s)?
Replace the upstream O2 sensors, not the downstream ones. Leave the downstream ones alone.
To keep the P0430 code from coming back, you want the upstream O2 sensor to switch faster than the downstream sensor.
O2 sensors start switching slower as they age, so it would stand to reason that replacing the upstream O2 sensors and leaving the downstream ones alone might change the upstream/downstream switch ratio enough to make the P0430 code go away. Might being the key word. I can't promise anything.
Also, I talked with my mechanic about how the B12 Chemtoool seemingly fixed the cat, and he mentioned that carburetor cleaner heats the cats up, which might be the sort of "kick start" they need to start working efficiently.
So before you replace those cats, might I suggest spraying some B12 Chemtool or other carb/throttle body cleaner into the intake with the engine running? When I did mine I sprayed the cleaner for 10 seconds while revving the engine, let the engine idle for 10 seconds without spraying any cleaner in, and did this until I'd used about half of a 16oz can.
If you use B12 Chemtool, it's got a powerful enough stream that you can spray it in from a foot away. Most of the throttle body cleaners have a weak stream and it's hard to spray them in effectively without completely removing the air duct.
What if you have the B12 but its not in a spray can, its a can you pour with. Is there any way I could use it?
You could try this:
Cleaning intake manifolds without removing them This procedure basically tells you how to suck the cleaner into the intake manifold via a hose.
It should produce similar results to using spray-in cleaner.
Like using a spray-in cleaner, it will clean more than just the intake manifolds, and will have the same effects on the cat.
By the way, I've never had to change the plugs after doing this, nor have I changed the oil. As far as the plugs go, I've never had one foul out on me, and as far as the oil goes, I figure that the cleaner will evaporate (I help it along by taking the car on a drive at highway speeds after doing this) and be dealt with by the PCV valve.
99,900 miles with no recurrance of the P0430 code.
101,800 miles with no recurrence of the P0430 code. I did have a false scare though--CEL came on and I scanned it, was some evaporative emissions code. (P1443 I think). I cleared it it and it never came back.
Thanks for the updates Brian, need to try this on my car...
Replaced both upstream O2 sensors today (Hands are all cut up too!), used cleaner like you said... before the swap, and also added a can of B12 to my fuel.
No check-engine lights so far after about 60 mile combined city/highway.
I will report more results after more milage.
Car has 103K miles, had original O2s, and P0430 codes..
thanks Brian!