|03-25-2013 01:33 AM|
Testing a cat in these cars is very simple. You replace both O2 sensors and if the CEL does not go off after 4 full drive cycles the cat is bad.
The fact is though that unless you put an automotive scantool on the car you don't know what your doing. A scan tool will give you readouts from both O2 sensors and comparing those readouts will tell you if the cat is bad or not - assuming that is, that the sensors are both OK.
Washing the cat only worked with old style cats that had metal foil substrate and "ball" style catalytic converters (metal can filled with ceramic or stainless steel balls with a specially coated surface). A mix of detergent (as a wetting agent) and citrus cleaner (loosens carbon but does not harm platinum) was used.
That does not work on the modern cats which use a different construction.
There is a tool for the rubber hangars, just get it from an auto parts store.
|03-24-2013 03:24 PM|
There are about 10 different listed possible culprits for triggering that error (P0420).
My own vehicle is apparently emitting that DTC. Along with P0455 and P0457 (false positive).
I believe in my own vehicle, that it may very well be the temperature sensor causing it.
It (the gauge) behaves very funny. Unless it's being accurate about the temperature fluctuating greatly (bad pressure cap affecting the boiling point?).
Before you even bother replacing it: Try cleaning it! Yes. I understand how foolish that may sound. But what is a potential $2 solution?
If at best, it truly is an old wives tale, and nothing but snake oil: It is $2. If it works: That is a $2 solution!
You can try removing the catalytic converter from the vehicle, and letting it soak in either laundry detergent or lacquer thinner. Let it soak in a bucket 24+ hours minimum (completely submerged).
If I'm not mistaken: It could also be the thermostat malfunctioning, which would be affecting the coolant's temperature, which would be affecting the O2 sensors.
After a moment of Googling, I found this from some forum, "14. If the thermostat open just a bit too soon, and the engine never quite reaches operating temp, the ECM will continue to provide a little bit of enrichment. Meanwhile on the other side of the ECM the O2 is reporting a rich condition. If this goes on for too long it may be recorded as a mixture code that may interpreted as a bad O2."
In short: Instead of randomly replacing parts: You should try to really diagnose the problem first.
You can use a multimeter to check the O2 sensors (http://www.ehow.com/how_4870344_do-v...en-sensor.html).
You can test the thermostat by dumping it in a pot of boiling water (use a thermometer to check the water's temperature first).
You can test the engine temperature sensor with a multimeter (http://www.youtube.com/watch?v=wFHWpgHMAvY or this: http://www.youtube.com/watch?v=G7pE7DQBSV8).
You can test a whole array of things with just a simple multimeter, and basic knowledge. That should really narrow it down and pin-point it to BEING the catalytic converter.
But back on that subject (replacing the catalytic converter): I have a 2001 Ford Focus ZX3 MTX-75.
The only real question I have is regarding the 'hangers' or 'shock absorbers' or 'rubber grommets' that hold up the pipes (and catalytic converter).
How are you supposed to properly uninstall, and reinstall those? I haven't spent much time researching it.
|02-25-2013 09:53 PM|
|02-25-2013 09:41 PM|
If the emery cloth thing does not work and your really hard up for cash then try replacing just the front O2 sensor first and give it some time. The theory is that if the front O2 sensor is bad then your exhaust mixture will be wrong and the cat won't reach operating temperature, thus the downstream o2 might get sooted up. When the upstream O2 is working then the cat is likely going to be working, it will be at operating temp, and that may "clean" the downstream o2.
Also in the cheap fix dept. make sure that the gasket upstream of the cat is not leaking. There's a big gasket on the flange that has 3 bolts that hold it together, right above the cat.
But yes, in my case I was getting that code and I replaced both sensors. That was 3 months ago and it's still working fine. But of course I was planning on replacing the cat if I had to.
Don't you have a pick-and-pull wrecker nearby?
Also one other thing - no insult intended here - but many if not most states have emissions repair programs for low income residents. If your on unemployment or something like that, then contact the state as you may get a voucher or some such to get the thing repaired.
Good luck and let us know how it works out.
|02-21-2013 07:16 PM|
|coldbear||Cats do not just go bad. People kill em with bad gas and additives. Pull the o2 sensors out and clean the thermocouples(can) around it with emeory cloth. Thread em back in with never sieze , reset you code light and put a bottle of Sea Foam or a pint of Colemans Camp Fuel to the gas tank. I doubt the cat. is bad. Drive it like you stole it . All's will be well again.|
|02-21-2013 01:34 PM|
|Zeroe31890||You said that you had error code P0422. When you changed both 02 sensors that actually worked? Cuz I dont have the money to replace a cat and inspection is in a few days.|
|02-07-2013 01:14 PM|
they need to clear the codes to make sure the evap code does not come back.
if you did not tell them to fix the catcon code then they won't admit to fixing it because they do not want to warranty the work. But, if the mechanic is in there fixing something else and he happens to see a quick 1 minute fix like replacing a connector that got unplugged, most of them will do it and then just not record anywhere that they did it. That way, if the quick fix didn't fix anything the customer doesen't know the difference, and if it did fix something then the customer is going to be happy. (and if it breaks a week later again, then the customer won't want it fixed for free)
|02-07-2013 10:59 AM|
|Zeroe31890||Hmm, are they suppose to clear the codes? If it matters, the lady at the desk told me that the engine light would still be on, but its not. I am not sure if she meant it will eventually come on again. I hope it was a loose o2 sensor though because I saw the mechanic wiggle, disconnect, and reconnect the upstream o2 sensor. But I appreciate your advice a lot!|
|02-07-2013 08:51 AM|
|tmittelstaedt||Hmmm....I suspect that either one of 2 things happened. Either when they were fixing the evap system the mechanic discovered one of the O2 sensors was unplugged or the sensor was just loose and tightened it, or when they cleared codes, it erased both codes and whatever is setting the P0422 code is only doing it intermittently. In which case if you have emissions inspection next month you might be able to slide through. If the light goes on again just go to an auto parts store and ask them to clear the codes and see if the light stays off for a while.|
|02-07-2013 07:31 AM|
|Zeroe31890||Its not that I didn't listen to you haha. I went to a ford dealership and they told me I have to change it. But there was also an evap leak. I didn't have the money for a $1200 converter, so I told them to just fix the evap. They have, and so far, the engine light has been off. I am crossing my fingers that was actually causing the o2 sensors to go crazy. Come inspection time, which is in a month, I must change it if I fail due to the cat actually needing to be replaced. Hence why I ask. But I havent made any commitments to replace it until inspection if it even needs to be changed. Just asking the question because of issues with aftermarket parts and some cars. Since we got experienced ford focus people here, I figure the question is good here.|
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