P0430 code

**Cutlass** · 10-05-2010, 04:41 AM

here's a good thread on a high rpm backfire out the exhaust. Maybe something in there help you.
http://www.ls1.com/forums/showthread.php?t=133286

**98TransAmWs-6** · 10-05-2010, 08:50 AM

Originally Posted by Cutlass

here's a good thread on a high rpm backfire out the exhaust. Maybe something in there help you.
http://www.ls1.com/forums/showthread.php?t=133286

Thanks, but that thread talks about it out of the intake at least what I read did.

**98TransAmWs-6** · 10-05-2010, 10:30 AM

I know I don't have an exhaust leak. The shop I go to said that the misfire has clogged the cat and they can do this fuel injection system cleaner that goes through all the vacuum lines and everything that will clean out the cats. Does this sound like it will work? It's not just the normal stuff you can buy at any autoparts store that you put in the fuel tank btw. Say it does clean my cat and the code goes away the backfire or "afterfire" w/e you wanna call it should go away too right? It's not a separate problem?

**Cutlass** · 10-05-2010, 05:29 PM

no fuel injection cleaning service will ever clean out a cat converter. And the vacuum line cleaners in my opinion, don't do much and are a waste of time. The fuel injection cleaning services that run high detergent gas through the injectors is a decent, legit service.
My gut feeling is that you have 2 separate problems. You have a backfire and converter issue.

**98TransAmWs-6** · 10-05-2010, 10:30 PM

If I have a clogged cat would gutting the cat fix that problem? And yes I know it's illegal but I don't need testing for another 2 years. I just don't feel like spending the money on a new cat.

**Too Fast** · 10-06-2010, 03:41 AM

No gutting the cat will not eliminate the P0430 code, it will come right back. And I also think you have 2 problems, the "backfiring" being the 2nd. And gutting it won't help any backfiring.

Have you had your fuel pressure checked, esp. at high speeds/loads? Could be your fuel pump is a tad low on output (partially clogged fuel filter could cause that), or a dirty MAF.

You say your convertors are ~1 month old, you should not have to buy one, they should be under a warranty. Contact OBX and explain.

The fuel injection service thru the vacuum lines is a maintenence service, it won't clean the cats. The person who said that doesn't know what they are talking about.

**98TransAmWs-6** · 10-06-2010, 06:33 AM

I know just gutting that cat won't make the code go away but I was thinking of gutting them if for some reason obx won't replace them and getting a tune to tune the O2s out. If a clogged cat is causing the backfire wouldn't gutting them make the backfire go away? I'll try changing my fuel filter I have one laying around anyways, it's just weird how the backfiring and cat code only came up after it came back from the shop I took it to.

**Too Fast** · 10-06-2010, 05:58 PM

^^^I don't see how "adjusting the exhaust" is related to a driveability problem, unless they bumped a plug wire somewhat. I guess it's possible a clogged cat could cause a high RPM issue like you describe, since our cars have a convertor for each bank, but not likely. Usually a clogged cat will cause low power, not a misfire/backfire.

The rear O2 sensor measures the ability of the convertor to store O2. If the rear O2 sensor does not have the correct delay before it senses the O2 that is specified by the PCM when the PCM performs the efficiency test, it will set the code. Therefore, if a convertor is clogged, it will usually not set the code, since no/slow flow=delay. The convertors' ability to store O2 is determined by the availabilty of a certain precious metal in the convertor, I can't remember if it is specifically platinum, rhodium, palladium or what it was. I should remember, I just went to a class on this!

**98TransAmWs-6** · 10-07-2010, 07:59 AM

Sorry if I don't quite understand what you are saying but what exactly happens when a cat goes bad besides getting clogged? Also, you said if the O2 sensor doesn't have the correct delay it will set the code so could it be messed up O2s that got screwed from the misfire I had? I know that it is most likely my cats are messed up but I just would like to know of a way to rule something out and know for sure that is the problem so I am not wasting money.

**Cutlass** · 10-07-2010, 08:14 AM

yes there is/can be a difference between a cat clogging up and a cat setting a P0430 trouble code.
When a cat clogs up...well thats obvious. it restricts exhaust flow and you'll feel the affects of that.
When a cat sets a P0430 code, it likely that the cat will flow the exhaust exactly like a brand new cat. The only thing wrong with the cat is that it no longer "cleans" the exhaust like its suppose to.

**98TransAmWs-6** · 10-07-2010, 08:50 AM

Originally Posted by Cutlass

yes there is/can be a difference between a cat clogging up and a cat setting a P0430 trouble code.
When a cat clogs up...well thats obvious. it restricts exhaust flow and you'll feel the affects of that.
When a cat sets a P0430 code, it likely that the cat will flow the exhaust exactly like a brand new cat. The only thing wrong with the cat is that it no longer "cleans" the exhaust like its suppose to.

Well if it's that they don't clean like the computer wants them to, couldn't it just have been set because they are high flows? I think I asked this before sorry if I asked it again and I am guess no because the code didn't show up until now. It's the backfiring that bothers me I don't really care if it isn't cleaning the exhaust like it's suppose to. What causes it to not clean like it's suppose to though? If there isn't really a problem with the cat itself like it's not damaged I'll probably ignore the code for now or get a tune and have the rear O2s tuned out. Besides the fuel filter what are other causes of a backfire in the exhaust?

**Cutlass** · 10-07-2010, 10:59 AM

Originally Posted by 98TransAmWs-6

Well if it's that they don't clean like the computer wants them to, couldn't it just have been set because they are high flows?

Yes

**98TransAmWs-6** · 10-07-2010, 12:50 PM

Originally Posted by Cutlass

Yes

So how do I know if that is the case? and how do I fix if it is? A tune?

**bdub2145** · 10-07-2010, 04:50 PM

i put the same exhaust on my buddies firehawk and he ran the o2 dummy plugs and never set a code on his and yes the o2s not being plugged in could set the code but it would also set an o2 sensor code .

**bdub2145** · 10-07-2010, 04:53 PM

now is it backfiring or is it just doing a popping sound on decel .

**Marc 85Z28** · 10-07-2010, 06:30 PM

Originally Posted by 98TransAmWs-6

So how do I know if that is the case? and how do I fix if it is? A tune?

It IS the case. Again, ALL aftermarket converters are cheaply made, regardless of the brand or price. They do not use the proper amount of precious metals as the OEMs do.

The only way to fix it is with OEM converters. You can mask it with a tune, eliminating the rear sensors completely.

A P0420/P0430 can ONLY BE SET by an inefficient converter, and NOTHING ELSE. Not a clogged cat, not a PCM calibration, not a failing O2.

**98TransAmWs-6** · 10-07-2010, 08:02 PM

Originally Posted by Marc 85Z28

It IS the case. Again, ALL aftermarket converters are cheaply made, regardless of the brand or price. They do not use the proper amount of precious metals as the OEMs do.

The only way to fix it is with OEM converters. You can mask it with a tune, eliminating the rear sensors completely.

A P0420/P0430 can ONLY BE SET by an inefficient converter, and NOTHING ELSE. Not a clogged cat, not a PCM calibration, not a failing O2

Would it be more of the computer thinking it's not efficent because it's less efficent than the oem cats in retrospect of cleaning the exhaust fumes rather than letting more air out. What I am asking is if the cat is broken. As in I need to replace it. If I can get the O2s tuned out and it will make the code go away and if the cats aren't broken then I am going to do that since I am not going to run with oems they are too restrictive and outrageously expensive. I would just gut them and delete the rear sensors if I knew I would be able to pass emissions here in Northern Virginia but I don't know what the levels of emissions your car has to put out to pass and I think by gutting the cats I wouldn't.

Originally Posted by bdub2145

now is it backfiring or is it just doing a popping sound on decel .

It sounded like a backfire but it may have just been a popping sound and it was on high rpms not while deceling.

**Too Fast** · 10-08-2010, 03:49 AM

Originally Posted by Marc 85Z28

It IS the case. Again, ALL aftermarket converters are cheaply made, regardless of the brand or price. They do not use the proper amount of precious metals as the OEMs do.

The only way to fix it is with OEM converters. You can mask it with a tune, eliminating the rear sensors completely.

A P0420/P0430 can ONLY BE SET by an inefficient converter, and NOTHING ELSE. Not a clogged cat, not a PCM calibration, not a failing O2.

Originally Posted by 98TransAmWs-6

Would it be more of the computer thinking it's not efficent because it's less efficent than the oem cats in retrospect of cleaning the exhaust fumes rather than letting more air out. What I am asking is if the cat is broken. As in I need to replace it. If I can get the O2s tuned out and it will make the code go away and if the cats aren't broken then I am going to do that since I am not going to run with oems they are too restrictive and outrageously expensive. I would just gut them and delete the rear sensors if I knew I would be able to pass emissions here in Northern Virginia but I don't know what the levels of emissions your car has to put out to pass and I think by gutting the cats I wouldn't.

It sounded like a backfire but it may have just been a popping sound and it was on high rpms not while deceling.

Marc85Z is correct about one reason the aftermarket is less expensive.

98TransAm, your analysis of the convertor is correct, it doesn't scrub the air as good as an OE convertor does, but *may* flow a bit better than OE. It'd probably pass an idle emissions test, but maybe not a loaded simulation like some states require (VA?). And you are also right, even if you get the rear O2s tuned out, and also gutted the convertors, you will not pass emissions if they actually test your exhaust. If it were me, I'd have the convertor people warranty the bad cat. Tell them it keeps setting an efficiency code, I bet they've seen it before on these applications, and should exchange yours for another no problem.

**98TransAmWs-6** · 10-08-2010, 06:05 AM

Originally Posted by Too Fast

Marc85Z is correct about one reason the aftermarket is less expensive.

98TransAm, your analysis of the convertor is correct, it doesn't scrub the air as good as an OE convertor does, but *may* flow a bit better than OE. It'd probably pass an idle emissions test, but maybe not a loaded simulation like some states require (VA?). And you are also right, even if you get the rear O2s tuned out, and also gutted the convertors, you will not pass emissions if they actually test your exhaust. If it were me, I'd have the convertor people warranty the bad cat. Tell them it keeps setting an efficiency code, I bet they've seen it before on these applications, and should exchange yours for another no problem.

So far they haven't responded to me. But is the converter actually damaged meaning the "filter" inside them as in I do need new ones? or is it just because it is an aftermarket cat so it sets the code since it's not as efficient as oem ones. Basically I am asking if they are working just as they should but just setting the code or if I do need to have them replaced. I have this small jerk at idle, anyone know what causes that? It is barely noticeable.

**Cutlass** · 10-08-2010, 07:02 AM

there isn't any way to really tell over the internet. Possibly if you fix the rest of your running problems, the converter might pass the on board tests.