Code P0430 Catalyst effieciency low Bank 2

[chriskramerjr81]

Hi folks. 05 4 door explorer 4.0 liter and its being rotten. I got a code and went to Autobone...yea autobone and it came back p0430 cat. effic. low Bank 2. Now i just replaced a rocker arm in this thing a week ago it had a pressed pin in the arm that was actually coming out of it thank god it didnt fall out all the way but anyhoo it runs good. It runs good until you give it gas. It was fine until one day i was going up a hill and hit the gas and this blinking light(CEL) came on and the engine was just not going. Let off the gas and it would shift and it would go just fine until you had to punch it again and then blah . Now im a pretty decent mechanic and have done many things on just about anything you can think of but cats. are not my forte. Has anyone had this problem and what was the permanent fix? Im guessing it could be the cats, O2 sensors dont know which, fuel filter?, sensor of some kind or something im over looking. The cats arent all glowing red after good heating up and i can rev it up fine while in park with good throttle response. I have access to any diagnostic/tuning tool needed and was also wondering if a guy can run these with the cats chopped off and straight piped and then shut off the downstream O2 sensor. Will it run right thats all i need to know not worried about the CEL ill pull that S.O.B. bulb if i must but i just want to know if it will run right and if i cut out one cat do i have to cut the other cat out as well or just the one that shot if that indeed is the problem. Anyone who knows this issue will your input will be greatly appreciated.

 

[matt0248]

Sounds like a plugged Converter. You can get a backpressure tester to check back pressure. You can either put it in place of the oxygen sensor, or you drill and tap a small hole in the exhaust in front the of the converter. The back pressure should be really low, less than 1 or 2 psi, Check it under load also revving up the engine, if it goes up you have a plugged converter.

I would not recommend removing the Converters under any circumstances. But, they so sell cheater plugs that trick the computer into thinking the downstream sensors are ok. I am failrly certain that these have three converters. One on each hank of the engine and one after the two banks are y-ed together. If it is a plugged cat, I am not shure what replacement parts are available.

 

[waskly]

p0430 means the left side cat is bad. only the monitored cat.

 

[waskly]

Sounds like a plugged Converter. You can get a backpressure tester to check back pressure. You can either put it in place of the oxygen sensor, or you drill and tap a small hole in the exhaust in front the of the converter. The back pressure should be really low, less than 1 or 2 psi, Check it under load also revving up the engine, if it goes up you have a plugged converter.

I would not recommend removing the Converters under any circumstances. But, they so sell cheater plugs that trick the computer into thinking the downstream sensors are ok. I am failrly certain that these have three converters. One on each hank of the engine and one after the two banks are y-ed together. If it is a plugged cat, I am not shure what replacement parts are available.

p0430 will not set for a clogged cat btw.

 

[imp]

How commonly do cats get clogged? I have never seen one. Rumor was back when leaded fuel was still available, it would gum up cats. imp

 

[waskly]

How commonly do cats get clogged? I have never seen one. Rumor was back when leaded fuel was still available, it would gum up cats. imp

they get clogged, just when they do, you do not get a cel.

 

[chriskramerjr81]

Alright boys i got the tester on it today and in bank 2 the Oxy. sensor in front of the drivers side converter closest to engine i ran the test and at 1800 rpm i got 5 lbs of Back press and at 2200 rpm i got a flat 6 psi. Now im only certain of one thing and it means in my opinion that this test can only rule out the pass side converter from being the problem but that still leaves me with the front drivers side converter and the one where it Y's together to one pipe and also the muffler. The muffler should be able to cause this code and issue i think but im not sure. This is an 05 truck i just have a hard time believing it couldve plugged the converter anywhere. Now who said that someone sells an O2 trick sensor that can fool the downstream sensor? Anyone hear of this? Any links? Ideas? Tommorrow im gonna yank the muffler and run it and see if my acceleration improves and if it dont im gonna ram out that converter that is at the "y" in the pipes and if it still dont improve it has to be the drivers side front converter. With six psi back pressure something has to be stuffed up im just gonna chase it from the back up and if anyone else has a better idea that can save work, money or both pleae let me know.

 

[chriskramerjr81]

i just had another idea . What if i took the pressure test pre and post the suspected plugged part. I already took the back pressure test up in the front drivers side o2 sensor bung, pre-cat and got 6 psi . What if i took it after that cat and had 0-1 psi like im supposed to wouldnt that tell me that the front cat is bad? And what if i still had the 6 psi pressure after it it would have to be the muffler or the converter that y's the front two converters together wouldnt it?

 

[matt0248]

How commonly do cats get clogged? I have never seen one. Rumor was back when leaded fuel was still available, it would gum up cats. imp

imp,
When i was working in a shop for 10 years we saw quite a few get clogged. Not usually on Fords but it could happen. They don't get completely plugged just enough to cause too much backpressure and cause running problems. we had several GM cars and trucks that were replaced under the 80,000 mile emissions warranty.

Waskly,

Plugged cat will turn on a SES, usually MAF or Missfire codes. not efficiency codes, you are right about that.

chriskramerjr81,

Compare you backpressure readings to the other bank and see what you get. By you description of the running issues it really does sound like a plugged converter. 6 PSI is kinda high for backpressure.

Converters can become "worn" and not function properly. To set effeciency codes, the PCM looks and the upstream O-2 sensor and compares it to the downstream O-2 sensor. The upstream sensor should be very active, varifying between .1 and .9 V, the downstream sensor should be pretty stable. So when the downstream starts switching at a rate that is too close to the upstream it pops the code. It is possible to have a degraded upstream sensor that is switching too slowly. Trying a new sensor is cheaper than a new converter, I would guess.

 

[waskly]

Waskly,

Plugged cat will turn on a SES, usually MAF or Missfire codes. not efficiency codes, you are right about that.

plugged cats will not throw a cel light, there is no p code for restricted exhaust on a gas car.

while i agree you get a drive ability problem, 99% lack lose of power, stumbles, cant get out of its way, to even miss fire, there is no code for cats are clogged.

 

[waskly]

Converters can become "worn" and not function properly. To set effeciency codes, the PCM looks and the upstream O-2 sensor and compares it to the downstream O-2 sensor. The upstream sensor should be very active, varifying between .1 and .9 V, the downstream sensor should be pretty stable. So when the downstream starts switching at a rate that is too close to the upstream it pops the code. It is possible to have a degraded upstream sensor that is switching too slowly. Trying a new sensor is cheaper than a new converter, I would guess.

this would throw a o2 switch code, as the o2 is switching late, just saying the dude has a cat eff code, he needs an upstream cat, there is no go around it, he can chuck every part he would like at the car but the fix is a cat.

 

[chriskramerjr81]

Fixed it!!!!!

Waskly nice try but you were only partially right. The ds cat is blown. It chucked its ceramics past the y pipe and into the muffler like i thought. I tapped it with a rubber mallet and heard tons of junk in it. So i unhooked it and let it hang and took off down the road and wala it has balls again. I chopped the welded portion off on the back of the muffler and shook it out and i got about two soda cans worth of ceramics from the Drivers cat. I welded a piece of pipe over the mufller cut and clamped it to the tailpipe and it dont leak and i have all kinds of balls. I cleared the P0430 code but i am suspecting it will come back due to the blown cat but ill either find a way to disable the downstream O2's or just yank the damn bulb. Not worried so much about the light as much if it just runs right and it now does. I knew id get it but with all the welding being done on these exhausts now they make it nearly impossible to do anymore and i was dreading putting in a piece of straight pipe or another cat so thanks to all who helped and tried but if anyone has any questions of me ill be glad to answer. Thanks again