Need Help with P0430 trouble code. (Catalytic converter)

Update: Need to borrow your smarts again!
My truck is a 1996 Silverado. 331,000 miles. As I mentioned before, on
my way to work Monday, "Service engine soon" started blinking. Truck
started bucking, barely driveable. Engine died. Towed home. Had a code
that just said "Multiple cylinder misfire". Ignition Control Module
tested bad. Replaced the module along with spark plugs and distributor
cap/rotor. Drove the truck about 12 miles as a test. Ran better than
ever. Drove it 40 miles next day. No problems. Today on my way to
work, "service engine soon" came on. Still runs fine Went to autozone
to have it scaned. Code P0430 "Catalyst efficiency low bank 2".
Probable cause:

1. Catalytic converter defective
2. Engine misfire or running condition
3. Large vacuum leak
4. engine oil leakage into exhaust valve guide seals, piston rings.

This is my daily driver and a high mileage truck. I really dont want
to put any more money than I have to into it. I know it is illegal and
I know it is a Federal crime. That being said can I somehow bypass the
converter if it is truely the converter. How can I tell if that is
what it is?I read somewhere that if you have an infared thermometer,
the inlet pipe should be 5 degrees colder that the exit. If it is not
it is plugged?

I have also heard it could be an o2 sensor. Something about the
voltage of the end o2 sensor shoudl be different than the beginning. I
have a gift card to harbor freight. They have an OBD 2 reader that
will read o2 sensors. Will this tell me if they are bad?

I am at a loss here and tapped out ofter shelling out 218 bucks for
the last repair and 400 bucks for the air conditioner before all this
happened. I appreciate any help!

stryped > wrote:
>Update: Need to borrow your smarts again!
>My truck is a 1996 Silverado. 331,000 miles. As I mentioned before, on
>my way to work Monday, "Service engine soon" started blinking. Truck
>started bucking, barely driveable. Engine died. Towed home. Had a code
>that just said "Multiple cylinder misfire". Ignition Control Module
>tested bad. Replaced the module along with spark plugs and distributor
>cap/rotor. Drove the truck about 12 miles as a test. Ran better than
>ever. Drove it 40 miles next day. No problems. Today on my way to
>work, "service engine soon" came on. Still runs fine Went to autozone
>to have it scaned. Code P0430 "Catalyst efficiency low bank 2".

I bet that's a red herring. That code means that the O2 level on the
output of the converter is high, meaning the converter isn't working right.
That has nothing to do with your original problem.

>This is my daily driver and a high mileage truck. I really dont want
>to put any more money than I have to into it. I know it is illegal and
>I know it is a Federal crime. That being said can I somehow bypass the
>converter if it is truely the converter. How can I tell if that is
>what it is?I read somewhere that if you have an infared thermometer,
>the inlet pipe should be 5 degrees colder that the exit. If it is not
>it is plugged?

If not, the catalyst isn't doing it's job. If you have two exit O2 sensors,
swap the sensors between the two sides and see if the error moves. If so,
it's a bad sensor or bad wiring. If not, the converter isn't working.

The converter not working could be because it's poisoned with junk, but if
the problem were because the exhaust going into it was screwed up, you would
see the primary O2 sensor out of range also.

>I have also heard it could be an o2 sensor. Something about the
>voltage of the end o2 sensor shoudl be different than the beginning. I
>have a gift card to harbor freight. They have an OBD 2 reader that
>will read o2 sensors. Will this tell me if they are bad?

No. It'll tell you what value is coming out of the sensor, but you can
get that with a multitester. Your question is whether that value is valid
or not.

>I am at a loss here and tapped out ofter shelling out 218 bucks for
>the last repair and 400 bucks for the air conditioner before all this
>happened. I appreciate any help!

If you have 331,000 miles on the original cat, a miracle has occurred and
you should be very pleased with it.

However.... is there any reason you need to replace it? If the vehicle is
driving fine and there is no emissions inspection, there's no real reason
to replace it right now if it is indeed bad.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

stryped wrote:
>
> Update: Need to borrow your smarts again!
> My truck is a 1996 Silverado. 331,000 miles. As I mentioned before, on
> my way to work Monday, "Service engine soon" started blinking. Truck
> started bucking, barely driveable. Engine died. Towed home. Had a code
> that just said "Multiple cylinder misfire". Ignition Control Module
> tested bad. Replaced the module along with spark plugs and distributor
> cap/rotor. Drove the truck about 12 miles as a test. Ran better than
> ever. Drove it 40 miles next day. No problems. Today on my way to
> work, "service engine soon" came on. Still runs fine Went to autozone
> to have it scaned. Code P0430 "Catalyst efficiency low bank 2".
> Probable cause:
>
> 1. Catalytic converter defective
> 2. Engine misfire or running condition
> 3. Large vacuum leak
> 4. engine oil leakage into exhaust valve guide seals, piston rings.
>
> This is my daily driver and a high mileage truck. I really dont want
> to put any more money than I have to into it. I know it is illegal and
> I know it is a Federal crime. That being said can I somehow bypass the
> converter if it is truely the converter. How can I tell if that is
> what it is?I read somewhere that if you have an infared thermometer,
> the inlet pipe should be 5 degrees colder that the exit. If it is not
> it is plugged?
>
> I have also heard it could be an o2 sensor. Something about the
> voltage of the end o2 sensor shoudl be different than the beginning. I
> have a gift card to harbor freight. They have an OBD 2 reader that
> will read o2 sensors. Will this tell me if they are bad?

You are not going to get much more info than you already have from a
code reader.
But a good code reader will be handy anyway. If you have a laptop you
can just get a USB/obdII adapter and the software (available on ebay and
elsewhere). You will be able to turn the code off, but the code may turn
itself off anyway.

the particular code you are getting is due to the built-in diagnostic
for the cat. It means the self-diagnostic test that triggers the code
indicates the cat is not consuming O2 as well as it should. The cat may
be weak or the 2nd O2 sensor may be weak or you may have an exhaust leak
or loose electrical connection that is throwing the test off.

The good news is this code usually does not indicate an engine problem
if there are no other codes to go with it. In other words, if you had a
vacuum leak or misfire or burning oil this code would not be the only
indication of your problem.

-jim

>
> I am at a loss here and tapped out ofter shelling out 218 bucks for
> the last repair and 400 bucks for the air conditioner before all this
> happened. I appreciate any help!

On Apr 27, 2:01*pm, jim <"sjedgingN0Sp"@m@mwt,net> wrote:
> stryped wrote:
>
> > Update: Need to borrow your smarts again!
> > My truck is a 1996 Silverado. 331,000 miles. As I mentioned before, on
> > my way to work Monday, "Service engine soon" started blinking. Truck
> > started bucking, barely driveable. Engine died. Towed home. Had a code
> > that just said "Multiple cylinder misfire". Ignition Control Module
> > tested bad. Replaced the module along with spark plugs and distributor
> > cap/rotor. Drove the truck about *12 miles as a test. Ran better than
> > ever. Drove it 40 miles next day. No problems. Today on my way to
> > work, "service engine soon" came on. Still runs fine Went to autozone
> > to have it scaned. Code P0430 "Catalyst efficiency low bank 2".
> > Probable cause:
>
> > 1. Catalytic converter defective
> > 2. Engine misfire or running condition
> > 3. Large vacuum leak
> > 4. engine oil leakage into exhaust valve guide seals, piston rings.
>
> > This is my daily driver and a high mileage truck. I really dont want
> > to put any more money than I have to into it. I know it is illegal and
> > I know it is a Federal crime. That being said can I somehow bypass the
> > converter if it is truely the converter. How can I tell if that is
> > what it is?I read somewhere that if you have an infared thermometer,
> > the inlet pipe should be 5 degrees colder that the exit. If it is not
> > it is plugged?
>
> > I have also heard it could be an o2 sensor. Something about the
> > voltage of the end o2 sensor shoudl be different than the beginning. I
> > have a gift card to harbor freight. They have an OBD 2 reader that
> > will read o2 sensors. Will this tell me if they are bad?
>
> You are not going to get much more info than you already have from a
> code reader.
> But a good code reader will be handy anyway. If you have a laptop you
> can just get a USB/obdII adapter and the software (available on ebay and
> elsewhere). You will be able to turn the code off, but the code may turn
> itself off anyway.
>
> the particular code you are getting is due to the built-in diagnostic
> for the cat. It means the self-diagnostic test that triggers the code
> indicates the cat is not consuming O2 as well as it should. *The cat may
> be weak or the 2nd O2 sensor may be weak or you may have an exhaust leak
> or loose electrical connection that is throwing the test off.
>
> The good news is this code usually does not indicate an engine problem
> if there are no other codes to go with it. In other words, if you had a
> vacuum leak or misfire or burning oil this code would not be the only
> indication of your problem.
>
> -jim *
>
>
>
>
>
> > I am at a loss here and tapped out ofter shelling out 218 bucks for
> > the last repair and 400 bucks for the air conditioner before all this
> > happened. I appreciate any help!- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -

Call me anal, but I hate any check engine light on. If the second 02
snesor measures how much 02 is being taken by the converter, I guess
taking the guts out of the inside of the converter would cause a code?

On Apr 27, 2:01*pm, jim <"sjedgingN0Sp"@m@mwt,net> wrote:
> stryped wrote:
>
> > Update: Need to borrow your smarts again!
> > My truck is a 1996 Silverado. 331,000 miles. As I mentioned before, on
> > my way to work Monday, "Service engine soon" started blinking. Truck
> > started bucking, barely driveable. Engine died. Towed home. Had a code
> > that just said "Multiple cylinder misfire". Ignition Control Module
> > tested bad. Replaced the module along with spark plugs and distributor
> > cap/rotor. Drove the truck about *12 miles as a test. Ran better than
> > ever. Drove it 40 miles next day. No problems. Today on my way to
> > work, "service engine soon" came on. Still runs fine Went to autozone
> > to have it scaned. Code P0430 "Catalyst efficiency low bank 2".
> > Probable cause:
>
> > 1. Catalytic converter defective
> > 2. Engine misfire or running condition
> > 3. Large vacuum leak
> > 4. engine oil leakage into exhaust valve guide seals, piston rings.
>
> > This is my daily driver and a high mileage truck. I really dont want
> > to put any more money than I have to into it. I know it is illegal and
> > I know it is a Federal crime. That being said can I somehow bypass the
> > converter if it is truely the converter. How can I tell if that is
> > what it is?I read somewhere that if you have an infared thermometer,
> > the inlet pipe should be 5 degrees colder that the exit. If it is not
> > it is plugged?
>
> > I have also heard it could be an o2 sensor. Something about the
> > voltage of the end o2 sensor shoudl be different than the beginning. I
> > have a gift card to harbor freight. They have an OBD 2 reader that
> > will read o2 sensors. Will this tell me if they are bad?
>
> You are not going to get much more info than you already have from a
> code reader.
> But a good code reader will be handy anyway. If you have a laptop you
> can just get a USB/obdII adapter and the software (available on ebay and
> elsewhere). You will be able to turn the code off, but the code may turn
> itself off anyway.
>
> the particular code you are getting is due to the built-in diagnostic
> for the cat. It means the self-diagnostic test that triggers the code
> indicates the cat is not consuming O2 as well as it should. *The cat may
> be weak or the 2nd O2 sensor may be weak or you may have an exhaust leak
> or loose electrical connection that is throwing the test off.
>
> The good news is this code usually does not indicate an engine problem
> if there are no other codes to go with it. In other words, if you had a
> vacuum leak or misfire or burning oil this code would not be the only
> indication of your problem.
>
> -jim *
>
>
>
>
>
> > I am at a loss here and tapped out ofter shelling out 218 bucks for
> > the last repair and 400 bucks for the air conditioner before all this
> > happened. I appreciate any help!- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -

I do have an exhaust leak but it is at the muffler, after the cat by
the way.

stryped wrote:

> Call me anal, but I hate any check engine light on. If the second 02
> snesor measures how much 02 is being taken by the converter, I guess
> taking the guts out of the inside of the converter would cause a code?

Yes. You did that on only one side?

stryped > wrote:
>
>Call me anal, but I hate any check engine light on. If the second 02
>snesor measures how much 02 is being taken by the converter, I guess
>taking the guts out of the inside of the converter would cause a code?

Yes, it would cause precisely the code you have.

Again, could be a sensor or wiring, or it could be a bad converter. Given
the mileage, a bad converter wouldn't be surprising.

I have cleaned gunked-up converters with acetone and had them work well
again once the catalyst was exposed again, though I can't recommend that
and it may not be legal (even if effective). But it's also possible to
have the catalyst just mechanically worn away after enough exhaust has
passed through there.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On Apr 27, 7:22*pm, (Scott Dorsey) wrote:
> stryped > wrote:
>
> >Call me anal, but I hate any check engine light on. If the second 02
> >snesor measures how much 02 is being taken by the converter, I guess
> >taking the guts out of the inside of the converter would cause a code?
>
> Yes, it would cause precisely the code you have.
>
> Again, could be a sensor or wiring, or it could be a bad converter. *Given
> the mileage, a bad converter wouldn't be surprising. *
>
> I have cleaned gunked-up converters with acetone and had them work well
> again once the catalyst was exposed again, though I can't recommend that
> and it may not be legal (even if effective). *But it's also possible to
> have the catalyst just mechanically worn away after enough exhaust has
> passed through there.
> --scott
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

Is there a way to bypass the converters and somehow fool the sensor
into working properly? Autozone has a "universal" converter for 73
bucks for one. I'd rather just do away with them if i could still get
the light to go off and for it to run properly.

By the way when it talks about "bank 2" for the code, which converter
is that on my 1996 350 silverado?

I appreciate it!

stryped > wrote:
>
>Is there a way to bypass the converters and somehow fool the sensor
>into working properly? Autozone has a "universal" converter for 73
>bucks for one. I'd rather just do away with them if i could still get
>the light to go off and for it to run properly.

No.

Either fix it or ignore the light.

If you're going to fix it, find out if it's the converter or not before
you go swapping the converter out.

>By the way when it talks about "bank 2" for the code, which converter
>is that on my 1996 350 silverado?

Dunno, but the manual will tell you. I suggest, though, first swapping
the outside O2 sensors between the two converters and seeing if the
problem moves to bank 1. If it doesn't, change the converter after
FIRST making sure there are no leaks in the exhaust system anywhere.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 4/27/2011 9:48 PM, stryped wrote:
> On Apr 27, 7:22 pm, (Scott Dorsey) wrote:
>> > wrote:
>>
>>> Call me anal, but I hate any check engine light on. If the second 02
>>> snesor measures how much 02 is being taken by the converter, I guess
>>> taking the guts out of the inside of the converter would cause a code?
>>
>> Yes, it would cause precisely the code you have.
>>
>> Again, could be a sensor or wiring, or it could be a bad converter. Given
>> the mileage, a bad converter wouldn't be surprising.
>>
>> I have cleaned gunked-up converters with acetone and had them work well
>> again once the catalyst was exposed again, though I can't recommend that
>> and it may not be legal (even if effective). But it's also possible to
>> have the catalyst just mechanically worn away after enough exhaust has
>> passed through there.
>> --scott
>>
>> --
>> "C'est un Nagra. C'est suisse, et tres, tres precis."
>
> Is there a way to bypass the converters and somehow fool the sensor
> into working properly? Autozone has a "universal" converter for 73
> bucks for one. I'd rather just do away with them if i could still get
> the light to go off and for it to run properly.
>
> By the way when it talks about "bank 2" for the code, which converter
> is that on my 1996 350 silverado?
>
> I appreciate it!

Passenger side