Strong Catalytic Converter Smell
01-03-13, 09:01 PM
#16
From my experience fixing my 420 and 430 codes I can tell you the car does not run as good with the post cat efficiency. I had this problem. Had both cats replaced and then it came back after 5,000 miles. I was getting 430 and resetting the ecu, which lasted 250 miles or so and then came back. I could feel that there was less power and mileage went down with the code set. I really believe the post cat 02's are used for more then just sniffing to see if you have cats or not. The car does not run the same and I'm pretty sure someone at Lexus said the ECM was in some kind of limp mode. Anyway, after correct cats were installed it is all good.
Last edited by Lavrishevo; 01-03-13 at 09:08 PM.
01-03-13, 09:21 PM
#17
Lexus Champion
I really believe the post cat 02's are used for more then just sniffing to see if you have cats or not. The car does not run the same and I'm pretty sure someone at Lexus said the ECM was in some kind of limp mode. Anyway, after correct cats were installed it is all good.
and they are not exactly sniffing to see if you have a cat, they are comparing the pre-cat and post-cat waveforms to see if certain emissions byproducts are below specified thresholds.
in fact - the title of 420 & 430 is Catalyst System Efficiency Below Threshold
to quote Toyota Engineering:
Air-fuel ratio feedback compensation keeps the waveform of the oxygen sensor before the catalyst repeatedly changing back & forth from rich to lean.
If the catalyst is functioning normally, the waveform of the sensor after the catalyst, switches back & forth between rich & lean much more slowly than does the waveform of the oxygen sensor before the catalyst.
But when both waveforms change at a similar rate, it indicates that catalyst performance has deteriorated.
my advice for your car:
1. fix the leak completely, it is amazing the magic that a good muffler shop can accomplish with an oxy-acetylene torch!
2. test both pre-cat O2 sensors as per the Lexus factory repair manual, replace if bad, also test post-cat O2 sensors as per manual
3. if you still have code & smell from passenger side and it bugs you or you have emission testing or environmental conscientiousness, then replace passenger side cat
Last edited by LScowboyLS; 01-03-13 at 09:44 PM.
01-04-13, 02:59 PM
#21
Lead Lap
Thread Starter
She is reading 430 only still.
Same as the past 2 years. bank 2 cat below efficiency.
Due too the common leak at the cat flange.
I guess my smell is due too that ecu running in an open loop and causing the car to run rich.
Even richer due to the cold weather causing the cats to work extra hard due to the extra fuel.
Leading to the wonderful smell.
Same as the past 2 years. bank 2 cat below efficiency.
Due too the common leak at the cat flange.
I guess my smell is due too that ecu running in an open loop and causing the car to run rich.
Even richer due to the cold weather causing the cats to work extra hard due to the extra fuel.
Leading to the wonderful smell.
01-04-13, 06:57 PM
#22
You can also do this. May take a little tweaking to get the emulator working perfect. If I found these before I purchased the cats I probably would of used them. I was able to get my third set of cats under warranty but not until replacing both rear 02 sensors. I was fighting 420 and 430 myself but with no leak. Aftermarket cats won't last on the 400 unless they are CA rated cats. More precious metals in them.
I remember a few Lexus techs I spoke too also mentioned running regular 87 significantly shortens the life on the factory cats. I had no problem talking to service managers and techs at various Lexus dealers around the country getting a consensus. Works pretty good.
I remember a few Lexus techs I spoke too also mentioned running regular 87 significantly shortens the life on the factory cats. I had no problem talking to service managers and techs at various Lexus dealers around the country getting a consensus. Works pretty good.
Last edited by Lavrishevo; 01-04-13 at 07:17 PM.
01-04-13, 08:19 PM
#23
Lexus Champion
the 420 & 430 codes cannot put the LS400 (or any other car in the universe that I can think of) into open loop, nor can codes related to the post-cat O2 sensors. The only O2 sensor related codes that can cause the car to go into open loop are the pre-cat codes, I feel I have been quite clear on this.
one reason manufacturers do this, is that running open loop causes bad emissions (as well as a bad smell) and it is not necessary to run the car in this rich inefficient way, nor is it good for the cats, just because of a bad cat or a bat post-cat O2 sensor or its associated heater circuit, as long as the pre-cat O2 sensors are functioning properly.
when he ran his car rich for these couple of years with the exhaust leak, he has very likely burned up his passenger side (bank 2) cat, hence the bad smell, yet still good engine performance.
Last edited by LScowboyLS; 01-04-13 at 08:54 PM.
01-04-13, 09:04 PM
#24
this statement is incorrect (and kind of invalidates your whole point in this thread)
the 420 & 430 codes cannot put the LS400 (or any other car in the universe that I can think of) into open loop, nor can codes related to the post-cat O2 sensors, the only O2 sensor related codes that can cause the car to go into open loop are the pre-cat codes, I feel I have been quite clear on this.
one reason manufacturers do this, is that running open loop causes bad emissions (as well as a bad smell) and it is not necessary to run the car in this rich inefficient way, nor is it good for the cats, just because of a bad cat or a bat post-cat O2 sensor or its associated heater circuit, as long as the pre-cat O2 sensors are functioning properly.
when he ran his car rich for these couple of years with the exhaust leak, he has very likely burned up his passenger side (bank 2) cat, hence the bad smell, yet still good engine performance.
the 420 & 430 codes cannot put the LS400 (or any other car in the universe that I can think of) into open loop, nor can codes related to the post-cat O2 sensors, the only O2 sensor related codes that can cause the car to go into open loop are the pre-cat codes, I feel I have been quite clear on this.
one reason manufacturers do this, is that running open loop causes bad emissions (as well as a bad smell) and it is not necessary to run the car in this rich inefficient way, nor is it good for the cats, just because of a bad cat or a bat post-cat O2 sensor or its associated heater circuit, as long as the pre-cat O2 sensors are functioning properly.
when he ran his car rich for these couple of years with the exhaust leak, he has very likely burned up his passenger side (bank 2) cat, hence the bad smell, yet still good engine performance.
P0430 is not, in fact, an Oxygen sensor code at all as it's not a "hard fault" code. It's a comparative code, indicating either loss of catalytic function (least likely), degradation of oxygen sensor function, or an exhaust leak (most likely).
from the FSM:
The ECM compares the waveform of the oxygen sensor located before the catalyst with the waveform of
the oxygen sensor located after the catalyst to determine whether or not the catalyst performance has deteriorated.
The air–fuel ratio feedback compensation keeps the waveform of the oxygen sensor before the catalyst repeatedly
changing back and forth from rich to lean.
If the catalyst is functioning normally, the waveform of the oxygen sensor after the catalyst switches back
and forth between rich and lean much more slowly than the waveform of the oxygen sensor before the catalyst.
But when both waveforms change at a similar rate, it indicates that the catalyst performance has deteriorated.
the oxygen sensor located after the catalyst to determine whether or not the catalyst performance has deteriorated.
The air–fuel ratio feedback compensation keeps the waveform of the oxygen sensor before the catalyst repeatedly
changing back and forth from rich to lean.
If the catalyst is functioning normally, the waveform of the oxygen sensor after the catalyst switches back
and forth between rich and lean much more slowly than the waveform of the oxygen sensor before the catalyst.
But when both waveforms change at a similar rate, it indicates that the catalyst performance has deteriorated.
OP get the codes read so we can all stop hypothesizing, if it's p0420/p0430 then just fix the exhaust leak so the car stops running rich then go from there.
01-04-13, 09:34 PM
#25
Lexus Champion
yes, you quoted the same part of the FSM that I quoted way back in post #17, catch up, man! 
I am, in fact, FULLY CORRECT, the post-cat O2 sensor codes cannot cause the system to go into open loop, only the pre-cat O2 sensor codes can. - I feel I have been quite clear on this. 
I even explained why manufacturers do it this way in my previous post #23, and this is not just LS400. I have never encountered any vehicle that is an exception to this.
Actually, upon double checking my manual, it seems you are only partially correct.
I even explained why manufacturers do it this way in my previous post #23, and this is not just LS400. I have never encountered any vehicle that is an exception to this.
01-04-13, 09:50 PM
#26
You both are incorrect. 
So, what is the ECM doing with 420 and / or 430 set? Where is Yaeme? Personally, my much less technical explanation was much better. And speaking of ECM's. When is someone going to finally figure out how to modify it a little and get at least 10 horsepower? Just a 93 octane tune is all I am asking for. Lean her out a bit. We need some engineers on this project. It's been done before. Just need to find a few samples and see what was modified. Break out those transistors and caps or whatever...
Edit: PD is actually correct now.
So, what is the ECM doing with 420 and / or 430 set? Where is Yaeme? Personally, my much less technical explanation was much better. And speaking of ECM's. When is someone going to finally figure out how to modify it a little and get at least 10 horsepower? Just a 93 octane tune is all I am asking for. Lean her out a bit. We need some engineers on this project. It's been done before. Just need to find a few samples and see what was modified. Break out those transistors and caps or whatever...
Edit: PD is actually correct now.
Last edited by Lavrishevo; 01-04-13 at 10:06 PM.
01-04-13, 09:54 PM
#27
yes, you quoted the same part of the FSM that I quoted way back in post #17, catch up, man!
I am, in fact, FULLY CORRECT, the post-cat O2 sensor codes cannot cause the system to go into open loop, only the pre-cat O2 sensor codes can. - I feel I have been quite clear on this.
I even explained why manufacturers do it this way in my previous post #23, and this is not just LS400. I have never encountered any vehicle that is an exception to this.
I am, in fact, FULLY CORRECT, the post-cat O2 sensor codes cannot cause the system to go into open loop, only the pre-cat O2 sensor codes can. - I feel I have been quite clear on this.
I even explained why manufacturers do it this way in my previous post #23, and this is not just LS400. I have never encountered any vehicle that is an exception to this.
see the attached image from the same FSM. Note please DTCs P0037, p0038, p0057, and p0058. All of which correlate to sensor no.2 in banks 1 and 2. (ie-post catalytic converter oxygen sensors.)
Apparently, Toyota disagrees with you.
01-04-13, 10:29 PM
#28
Lexus Champion
and yet you're posting no proof?
Notice the section in your diagram, the fail-safe operation that occurs when the P0037, p0038, p0057, or p0058 codes occur: The heater circuit in which an abnormality is detected is turned off
A heater is turned off, big whoop. This is far from going into open loop, so please correct yourself on this.
PD - you are a really smart guy, but when you "drift" away from drifting, suspensions, limited slip differentials and into things like ECU's, transmission theory, and A/C, you may be drifting into uncharted waters - hehe
01-04-13, 11:41 PM
#30
You posted the proof for me - thanks dude!
Notice the section in your diagram, the fail-safe operation that occurs when the P0037, p0038, p0057, or p0058 codes occur: The heater circuit in which an abnormality is detected is turned off
A heater is turned off, big whoop. This is far from going into open loop, so please correct yourself on this.
PD - you are a really smart guy, but when you "drift" away from drifting, suspensions, limited slip differentials and into things like ECU's, transmission theory, and A/C, you may be drifting into uncharted waters - hehe
Notice the section in your diagram, the fail-safe operation that occurs when the P0037, p0038, p0057, or p0058 codes occur: The heater circuit in which an abnormality is detected is turned off
A heater is turned off, big whoop. This is far from going into open loop, so please correct yourself on this.
PD - you are a really smart guy, but when you "drift" away from drifting, suspensions, limited slip differentials and into things like ECU's, transmission theory, and A/C, you may be drifting into uncharted waters - hehe
the "heater circuit" is referring to the oxygen sensor heater circuit. "Fail safe" mode is the ECU not going into closed loop. Hence, dead O2 sensor heater/short in circuit (EITHER sensor, pre or post) yields open loop only operation.