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Im trying to figure out a code P0430 I get about once per month since I took the car out of storage.
The car had a full tank of gas treated with Sta-Bil and was stored for about 6 months.
The MAF sensor was cleaned during summer 18' and a new air filter was installed.
When I took the car out of storage I got the first P0430 code. I said to myself it was probably the Sta-Bil treatment going through the system with the old gas acting up on the readings.
Cleared the code.
I got thought the full tank of gas, refueled with 94 octane and did the bi-annual oil change.
I did topping off the oil, middle of the gage and the car havent burn oil since then.
Today I got another P0430 and I decided to analyse the STFT and LTFT especially on Bank 2.
The first time I got the code on May 10 the values were the following:
STFT Bank 1: 6.3%
LTFT Bank 1: 2.3%
STFT Bank 2: 6.3%
LTFT Bank 2: 1.6%
RPM: 2200rpms
So if I do the maths:
Difference in %
Bank 1: 4%
Bank 2: 4.7%
-------------------------
0.7% difference = acceptable
Difference in actual number for LTFT
LTFT Bank 1
0.977
LTFT Bank 2
0.984
So everything seems very good from the STFT and LTFT and within acceptable limits of 10% difference and based on the acceptable part-load range of 0.7 to 1.32 (where 1 is considered no trims)
The second time I got the code P0430 June 5th the values were the following:
STFT Bank 1: -4.7%
LTFT Bank 1: 7.0%
STFT Bank 2: -7.0%
LTFT Bank 2: 4.7%
RPMs: 2360
If I do the maths:
Difference in %
Bank 1: 2.3%
Bank 2: -2.3%
--------------------------
4% difference = acceptable
Difference in actual number for LTFT
LTFT Bank 1
0.930
LTFT Bank 2
0.953
Again everything seems good from the STFT and LTFT except Bank 1 and Bank 2 have a difference lean/rich but within acceptable limits of 10% difference and based on the acceptable part-load range of 0.7 to 1.32.
I also experience what I can call rough idle after getting off the highway at a stop light.
The car have 149000kms
4 oxygen sensors were changed at 117000kms
Both catalyst converter were changed at 125032kms
Spark plugs were changed at 131575kms and will be redone soon.
I plan on cleaning the secondary air injection pump as I also get a P0491 code once in awhile.
I dont own a Durametric for the moment but I plan buying one so I dont have 02 voltage for the moment.
Anyway I would like to find what cause the cell.
As I dont see anything wrong with STFT and LTFT readings can you point out what I should try first?
I was really expecting weird readings from the fuel trims if an 02 or catalyst converter were faulty.
Is there something I dont understand?
Cleaning your MAF is not a reliable treatment. Only when it is dirty it might restore (temporarily) its functionality after cleaning, If it is old it makes sense to replace it.
Did you check the MAF sensor hot film voltage? With ignition on, engine off: It should read around 1.0V Porsche service manual indicates 0.9-1.1V as a okay range
Maybe it has nothing to do with your actual problem but my personal experience is that a more then 0.05 V offset is already detrimental for performance. The car will run fine without fault codes but will not pull as strong as compared to a new one.
Your looking at this from the wrong direction. The code P0430 "Catalyst System Efficiency Below Threshold Bank 2" has nothing to do with your fuel trims. The code is indicating that your Catalytic Converter for Bank 2 is no longer doing its job. The PCM monitors the Upstream O2 and Downstream O2 and compares the 2 against each other. In simple terms it monitors how often the signal switches from rich to lean once fully warmed up. To keep it really simple it is more or less like the upstream is watching what goes in to the CAT and the downstream is watching what comes out. They should never be the same (except during cold starts). When the PCM see's that the signals are the same or close to the same it understands that the CAT is no longer performing its emissions duties and is telling you so. Considering the age of most 996's it is no surprise to see this issue.
Now if you had Lean codes, Rich codes, O2 sensor codes or misfires i would suggest correcting those issues first as they could cause false reading. The reason it takes a while for the code to return is the PCM needs to see a lot of data before it will make that decision (it's called a readiness monitor).
Simply put.......You need a new Catalytic Converter for Bank 2 and it wouldn't surprise me if Bank 1 was quick to follow.
It is possible that the Converter that were installed do not meet the specs the PCM is looking for. What brand were they? Warranty?
Your looking at this from the wrong direction. The code P0430 "Catalyst System Efficiency Below Threshold Bank 2" has nothing to do with your fuel trims. The code is indicating that your Catalytic Converter for Bank 2 is no longer doing its job. The PCM monitors the Upstream O2 and Downstream O2 and compares the 2 against each other. In simple terms it monitors how often the signal switches from rich to lean once fully warmed up. To keep it really simple it is more or less like the upstream is watching what goes in to the CAT and the downstream is watching what comes out. They should never be the same (except during cold starts). When the PCM see's that the signals are the same or close to the same it understands that the CAT is no longer performing its emissions duties and is telling you so. Considering the age of most 996's it is no surprise to see this issue.
Now if you had Lean codes, Rich codes, O2 sensor codes or misfires i would suggest correcting those issues first as they could cause false reading. The reason it takes a while for the code to return is the PCM needs to see a lot of data before it will make that decision (it's called a readiness monitor).
Simply put.......You need a new Catalytic Converter for Bank 2 and it wouldn't surprise me if Bank 1 was quick to follow.
It is possible that the Converter that were installed do not meet the specs the PCM is looking for. What brand were they? Warranty?
Thanks for your replies!
I will try to add as much details as I can here.
Originally Posted by Silk
Did you check the MAF sensor hot film voltage? With ignition on, engine off: It should read around 1.0V Porsche service manual indicates 0.9-1.1V as a okay range
No I havent check the voltage but I will try to find the correct pins and test it.
The MAF sensor is also brand new and was changed by a Bosch unit, not from Porsche at 135000kms.
A new throttle body was also fitted at the same time.
Originally Posted by Mbren1979
Your looking at this from the wrong direction. The code P0430 "Catalyst System Efficiency Below Threshold Bank 2" has nothing to do with your fuel trims. The code is indicating that your Catalytic Converter for Bank 2 is no longer doing its job. The PCM monitors the Upstream O2 and Downstream O2 and compares the 2 against each other. In simple terms it monitors how often the signal switches from rich to lean once fully warmed up. To keep it really simple it is more or less like the upstream is watching what goes in to the CAT and the downstream is watching what comes out. They should never be the same (except during cold starts). When the PCM see's that the signals are the same or close to the same it understands that the CAT is no longer performing its emissions duties and is telling you so. Considering the age of most 996's it is no surprise to see this issue.
Now if you had Lean codes, Rich codes, O2 sensor codes or misfires i would suggest correcting those issues first as they could cause false reading. The reason it takes a while for the code to return is the PCM needs to see a lot of data before it will make that decision (it's called a readiness monitor).
Simply put.......You need a new Catalytic Converter for Bank 2 and it wouldn't surprise me if Bank 1 was quick to follow.
It is possible that the Converter that were installed do not meet the specs the PCM is looking for. What brand were they? Warranty?
Alright, I was under the impression that fuel trims would be out of range if the 02 sensors were bad. But I understand now how this thinking was wrong. Its in fact because the 02 are working correctly that I get this code.
I also dont have any other codes related with 02 sensors or misfires.
It is a possibility that the actual CAT installed doesnt meet the PCM requirements.
The past owner changed them.
I took a picture of the cats and I can read a reference number that doesnt tell me much.. You can read the reference code on the driver side CAT
Originally Posted by Paul Waterloo
From a book I have
Thanks Paul! I will study this and try to test what the document is pointing out ASAP.
Originally Posted by Silk
Topic starter writes that o2 sensors and cat converter were recently changed
Do you have a stock exhaust?
Yes and no... I had a factory sport exhaust that was retro fitted.
No more information about this except that they did everything and even installed a switch for opening and closing the baffles but I know it was not a stock option and was retro fitted.
That picture looks like aftermarket "universal" weld in converters. I have installed hundreds of Cats, both factory OE parts and aftermarket. What i have found is the OE always works perfect (duh, but who can afford them), the "direct fit" converters made by name brand exhaust companies almost always fit perfect and meet the happy requirements of the PCM. sadly i have seen WAY too many times where the exhaust shop special weld in one size fits all converters don't last and don't work right out of the box.
My suggestion would be to get the car (and CAT) up to operating temps and watch the upstream and downstream O2's. Compare them to each other watching the info as a graph. Start the car cold so you can see the how they will look if the cat is 100% shot. Picture this. When cold, or when the cat is shot, the front and rear O2's will be virtually identical graph's . When the CAT is hot and working normal the upstream should be switching constantly and the downstream should have little to no activity, maybe 1/3 of the upstreams activity if that. If you notice that once the CAT is hot the activity is close to the same you have confirmed a bad cat.
Then becomes the question of what killed it? Is it just a cheap part that doesn't meet criteria? Did someone drive for a prolonged time with a misfire and the unburnt fuel damage it? Is coolant leaking internal in the engine and being consumed in the combustion chamber?
Again, since you stated the fuel trims are within specs i wouldn't think its caused by the engine. I would suspect a cheap cat.....
That picture looks like aftermarket "universal" weld in converters. I have installed hundreds of Cats, both factory OE parts and aftermarket. What i have found is the OE always works perfect (duh, but who can afford them), the "direct fit" converters made by name brand exhaust companies almost always fit perfect and meet the happy requirements of the PCM. sadly i have seen WAY too many times where the exhaust shop special weld in one size fits all converters don't last and don't work right out of the box.
My suggestion would be to get the car (and CAT) up to operating temps and watch the upstream and downstream O2's. Compare them to each other watching the info as a graph. Start the car cold so you can see the how they will look if the cat is 100% shot. Picture this. When cold, or when the cat is shot, the front and rear O2's will be virtually identical graph's . When the CAT is hot and working normal the upstream should be switching constantly and the downstream should have little to no activity, maybe 1/3 of the upstreams activity if that. If you notice that once the CAT is hot the activity is close to the same you have confirmed a bad cat.
Then becomes the question of what killed it? Is it just a cheap part that doesn't meet criteria? Did someone drive for a prolonged time with a misfire and the unburnt fuel damage it? Is coolant leaking internal in the engine and being consumed in the combustion chamber?
Again, since you stated the fuel trims are within specs i wouldn't think its caused by the engine. I would suspect a cheap cat.....
Perfect thanks!
I would defenately need a Durametric one day...
Funny as it is I was about to buy one but I guess the money will go on new CAT.
I made a quick test and hammered both CAT on the car. Bank 1 is making a very bad metallic noise when it hit it while bank 2 doesnt make much sound.
Funny that bank 2 seems to be the problem.
I found on bank 2 side a small exhaust leak... I dont know yet if the joints are the problem or the little crack in the middle I will have to verify this ASAP.
I guess I can always tight the collars if there is a problem
Changing the CATs is defenately on the list...
My original plan was to change the injectors as a preventive maintenance but I guess CAT are more important for now.
Do you think I should re-use my actual 02 sensors or replace them?
As for the CAT I will defenatly go with aftermarket ones.. I just can't justify OE price..
Any suggestion about what to use (Still have to do some research about 200 cell cats)
I also found Pacesetter cats which are priced really low... anyone have exprience with theses?
Here a link from RockAuto: https://www.rockauto.com/fr/catalog/...converter,5808
The minor leaks at the joints are not much of a concern. If it is something you can hear then yes, clean the leak up some how. Some leaks are actually by design to allow moisture/water to exit the system.
As long as the O2 sensors are switching they should be o.k.
I have heard of the Bosal brand on rock auto... they are good.....not sure about the others....
Also to note. The code only means it is no longer emissions compliant. That dosent mean it is going to effect the car in any other way. I live in florida where we dont have emissions testing. Most customer opt not to repair them and just deal with the light ( My OCD won't allow a check engine light on).
On the other hand if the CAT is coming apart it can and eventually will cause a blockage in the exhaust which then will cause drivability issues. Now you can decide whats more important.....no compliant cats or new injectors...
I have never seen an aftermarket cat that works correctly or lasts more than a year. I'm not saying they don't exist, but the OEM cats are far superior.
I have never seen an aftermarket cat that works correctly or lasts more than a year. I'm not saying they don't exist, but the OEM cats are far superior.
Thanks for the direct link Paul!
You think it could worth the money and effort to buy used cats? I can't believe the previous owner let the shop throw the OEM ones in the trash........... Something I should know before buying, something I can ask to the seller.. milage on the units, usage or it doesnt even matter and its a matter of luck?
On a side note I was just about to ask a question about FVD Bromacher cats...
I was looking at their 100 cell but I guess I will need to clear codes all the time. Anybody use 100 cell cats without issues?
The reason why I was looking at 100 cell instead of 200 cell is the price difference.... They have a set of 100 Cell for PSE exhaust at 1200$us which make it interresting compared to 1700$us for the 200cell PSE.
I also would like to know the difference between ''Normal'' CAT and for PSE exhaust? I wasnt aware that there could be a fitment issue so what is the difference is there's any?
I want to change my actual cats not because of the code it throw once per month but because Im affraid they become blocked and damage the engine. I also dont have to pass emission tests where I live.
I plan on tracking the car a couple times per year with PCA, the car is not my daily driver and is used to have fun in the mountains but It also see some street use with my son and wife in the car.
Before I forgot I also found Schnell performance Sport Cat that are decently priced. Never heard of them before so I defenately have to gather more infos but I wonder how they perform. https://schnellperformance.com/produ...nverter-x-pipe
Thanks again for you help, couldnt be more satisfied to be a member of this forum!
Hugo
I've had good luck with 200 cell cats. Good performance, no warning lights or codes, pass annual emissions testing (required here). I've run them (two different sets, but both 200 cell cats) on a 3.4 and a 3.6, with stock ecu tunes.
06-06-2019 | 04:05 AM
Fault code P0430
