[Raag Sandhu]

Originally Posted by vikram_d

Sankar, if there is a secondary catalytic converter in your car then you will be able to see it easily. It will not be a part of the muffler. Let me explain how the setup would be if you had a secondary catalytic converter.


Single Catalytic Converter System Layout.
Exhaust manifold > Catcon > Primary muffler > secondary muffler

On dual catcon systems it is like this.
Exhaust manifold > Primary catcon > Secondary catcon> Primary muffler > secondary muffler.

The secondary catcon is never a part of the muffler as it is a replaceable part and hence is always kept separate.

Oh and normally in twin O2 sensor setups, the O2 sensors are placed before and after the primary catcon as this is the one that does most of the CO to CO2 conversion.

Edit: @Raag Sandhu - It's not the question of passing emissions control. Cars without catalytic converters can easily pass emission tests. But some people like me don't like having any extra lights glowing on the Instrument cluster, especially the CEL.

@Sankar - If possible can you measure the pipe diameter of the stock exhaust manifold and the after market one. I have a feeling the after market one is going to be slightly restrictive at higher RPM's.

Sure, Vikram, even I hate the devilish orange glow on my dash as much as you do therefore I constantly monitor the OBD scans with the Torque app for Android. Once a CEL pops up for the O2 sensor it is very hard to get rid of.

[Sankar]

Originally Posted by vikram_d

Sankar, if there is a secondary catalytic converter in your car then you will be able to see it easily. It will not be a part of the muffler. Let me explain how the setup would be if you had a secondary catalytic converter.


Single Catalytic Converter System Layout.
Exhaust manifold > Catcon > Primary muffler > secondary muffler

On dual catcon systems it is like this.
Exhaust manifold > Primary catcon > Secondary catcon> Primary muffler > secondary muffler.

The secondary catcon is never a part of the muffler as it is a replaceable part and hence is always kept separate.

Oh and normally in twin O2 sensor setups, the O2 sensors are placed before and after the primary catcon as this is the one that does most of the CO to CO2 conversion.

@Sankar - If possible can you measure the pipe diameter of the stock exhaust manifold and the after market one. I have a feeling the after market one is going to be slightly restrictive at higher RPM's.

Yep, i'll measure the pipe dia.

The Swift Diesel and the Petrol both use the same rear muffler according tot he parts catalogue. In the catalogue the Diesel has a simple pipe for the center piece and for the Petrol there is a muffler like thingy on the center pipe. It looks like i can put the center piece of the Diesel in the petrol. Now i checked out the prices of both pipes. The Petrol's pipe is costing around 6k and the Diesel's pipe is around 2k. So because of this price difference i'm wondering if the Petrol's pipe is just a muffler.

Originally Posted by Raag Sandhu

Two reasons why I would want to step in here:-

I own a Ritz ABS in India with no CEL issues
I own a 2005 Cadillac SRX AWD V8 notorious for CEL and other small niggling issues

Common point here being me the owner, I decided to give my two cents:-

CEL on with a P0420 code? No problem - The Caddy has had it since 2 years now and has passed emission tests in a jiffy. CEL light with a P0300 is a BIG problem since it indicates random midfire and is a pain the neck to solve especially with no particular cylinder misfiring at no particular time interval. I was asked to change all 4 O2 sensors for a couple of thousands which I opted out since I upgraded the brakes on the car instead.

Only issue I see is a slight increase in fuel consumption. So from 8.0kmpl to 6.7kmpl it doesnt really matter for the Caddy, considering fuel is cheap here. I drive 280 kms a day with a bit of a heavy foot so probably I am the culprit!!

So if your CEL is on with a p0420 code, just forget about it and drive!

There is drop in FE i guess, but if the sensor doesn't affect anything then why does the FE drop? As you must already know passing emissions is never a problem here in India

Like Vikram said that the CEL gets to him, the CEL light on the dash kind of bugs me too. Makes it look like something is wrong with the car. Its a mental block.

Originally Posted by Raag Sandhu

Sure, Vikram, even I hate the devilish orange glow on my dash as much as you do therefore I constantly monitor the OBD scans with the Torque app for Android. Once a CEL pops up for the O2 sensor it is very hard to get rid of.

In this case its because i got the headers installed. I'm now looking at things like these http://www.ubertechnics.com/o2_simulator_2.5.aspx to completely remove the sensor from the system.

[vikram_d]

Originally Posted by Sankar

The Swift Diesel and the Petrol both use the same rear muffler according tot he parts catalogue. In the catalogue the Diesel has a simple pipe for the center piece and for the Petrol there is a muffler like thingy on the center pipe. It looks like i can put the center piece of the Diesel in the petrol. Now i checked out the prices of both pipes. The Petrol's pipe is costing around 6k and the Diesel's pipe is around 2k. So because of this price difference i'm wondering if the Petrol's pipe is just a muffler.

Looks like K Series 1.2 has only one catalytic converter. If it had 2 of them, then you would have seen 2 muffler like things below the car and not only one as you have stated.

If only there was a way to get some fresh air to the second O2 sensor. That would surely solve your problem.

Edit: I may have missed this but what happens when you drive with the second O2 sensor not fitted in the bung, but just being connected to it's terminal? Logically the ECU should see the converter efficiency as ok because the second sensor will be reading fresh air and the error and CEL should not occur.

[Sankar]

Originally Posted by vikram_d

@Sankar - If possible can you measure the pipe diameter of the stock exhaust manifold and the after market one. I have a feeling the after market one is going to be slightly restrictive at higher RPM's.

Vikram the pipe dia of header primary is 3.5 cm as measured from the circumference. The stock primary measures 2.8cm at the manifold and it opens up to around 3cm once inside the pipe. Pipe dia wise this header doesn't seem restrictive at higher RPM and it didn't feel like that either.

Two things that i dislike about this header is; 1) the O2 sensor placement and 2) the collector design.

The collector looks good from the outside but internally there is a lot of scope for improvement, see the pics. From the work visible on the final collector i think the other two collectors won't be that much different either. What do you say?

Some pics i took of the header when it reached me.

From the outside



Manifold


Collector build not very good



Welding blobs

Originally Posted by vikram_d

Edit: I may have missed this but what happens when you drive with the second O2 sensor not fitted in the bung, but just being connected to it's terminal? Logically the ECU should see the converter efficiency as ok because the second sensor will be reading fresh air and the error and CEL should not occur.

I guess it would throw some kind of CEL, not sure what

[vikram_d]

Originally Posted by Sankar

I guess it would throw some kind of CEL, not sure what

Sankar, the pipe diameters seem ok. Try running the car for a few days with the second O2 sensor reading fresh air. You will have to find some way to remove the sensor from the bung and then tie it down in a place where it is out of harm's way and also does not have a chance of coming loose. But remember to leave this sensor connected to the wiring. I think this should solve your problem.

Right now the ECU is basically telling you that the catalytic converter is not working and this is because there is no catalytic converter in the system. . The ECU is basically taking a differential reading between the two sensors and deciding if the catcon is working or not. So feeding fresh air to the second sensor should be able to fool the ECU into thinking that the catcon is working fine.

[Sankar]

I disconnected and removed the O2S2 from the exhaust half an hour ago and in its place i installed the O2S1 sensor now the upstream sensor is reading inputs from 2 cylinders and i suppose its better than reading from 1. Had to extend the length of the wires though.

Sealed the bung of O2S1 with a sensor blanking nut and the second sensor is completely removed from the system.

Originally Posted by vikram_d

Sankar, the pipe diameters seem ok. Try running the car for a few days with the second O2 sensor reading fresh air. You will have to find some way to remove the sensor from the bung and then tie it down in a place where it is out of harm's way and also does not have a chance of coming loose. But remember to leave this sensor connected to the wiring. I think this should solve your problem.

Right now the ECU is basically telling you that the catalytic converter is not working and this is because there is no catalytic converter in the system. . The ECU is basically taking a differential reading between the two sensors and deciding if the catcon is working or not. So feeding fresh air to the second sensor should be able to fool the ECU into thinking that the catcon is working fine.

If i hang it somewhere in the engine bay i think i'm going to get the error code P2270 which means "O2 Sensor Signal Biased/Stuck Lean". The supplementary service manual of the new Swift has this code in it so i think the 2nd O2 does more than evaluate the catcon. But there is no failsafe operation given against this code so i think its not the best for efficiency but OK.

As per the service manual the DTC codes associated with the 2nd O2 Sensor in the Swift K12M VVT are P0036, 37, 38, 137, 138, 140, 2270 and 2271.

[Sankar]

Pic of the upstream O2 sensor mounted after the 1st collector now its reading from 2nd and 4th cylinders. Since yesterday after i made this change I can feel a slight improvement in midrange torque.

Originally Posted by vikram_d

So feeding fresh air to the second sensor should be able to fool the ECU into thinking that the catcon is working fine.

Vikram, today i did what you have been telling me since some time, i connected the 2nd O2S to the harness and mounted it inside the engine bay. I cleared the code and lets see.. hope that it stays fixed..fingers crossed!

Since the O2S gets hot during regular operation i installed the sensor in the extender and mounted mounted it onto the head using a metal hose clip.

[1self]

With the 2nd O2 sensor disconnected, you will not get a CEL on the dash, but I'm pretty sure a code will be stored in ECU memory which can be retrived using a scan tool.

[Sankar]

Originally Posted by 1self

With the 2nd O2 sensor disconnected, you will not get a CEL on the dash, but I'm pretty sure a code will be stored in ECU memory which can be retrived using a scan tool.

On this car it does turn on the CEL when 2O2S is disconnected, the error returned was P0036.

[vikram_d]

Originally Posted by Sankar

Vikram, today i did what you have been telling me since some time, i connected the 2nd O2S to the harness and mounted it inside the engine bay. I cleared the code and lets see.. hope that it stays fixed..fingers crossed!

Since the O2S gets hot during regular operation i installed the sensor in the extender and mounted mounted it onto the head using a metal hose clip.

I have a feeling that this should work. Well at least we can hope that it works. Please keep us updated on how it goes.

[Sankar]

Originally Posted by vikram_d

I have a feeling that this should work. Well at least we can hope that it works. Please keep us updated on how it goes.

Done around 800Kms since this mod and so far no CEL. Working good

Not sure why this is not returning an error since theoretically it should give a "No Activity" error because the voltage returned by O2S2 is ZERO!!

[vikram_d]

Originally Posted by Sankar

Done around 800Kms since this mod and so far no CEL. Working good

Not sure why this is not returning an error since theoretically it should give a "No Activity" error because the voltage returned by O2S2 is ZERO!!

It's reading our polluted air and thinking that everything is fine. I really cannot believe that this worked. My recommendation was just based on a hunch.

Edit: Or the ECU is seeing zero voltage as a sign that the catcon is working efficiently, event though there is no catcon.

[Sankar]

Originally Posted by vikram_d

It's reading our polluted air and thinking that everything is fine. I really cannot believe that this worked. My recommendation was just based on a hunch.

Edit: Or the ECU is seeing zero voltage as a sign that the catcon is working efficiently, event though there is no catcon.

I think its because either this ECu doesn't support that particular "no Activity" condition or maybe because its still investigating the cause and would give the error after gathering sufficient evidence that its owner is trying to fool it

Below is the value the second O2 sensor should return if there was a catcon in the system. Took from one of the logs when i was running the stock exhaust. 0 voltage should give error normally, because of no activity.

Stock exhaust O2S1 and O2S2 voltage reading (with the catcon in place):
0.05 ---- 0.46
0.05 ---- 0.46
0.73 ---- 0.465
0.06 ---- 0.465
0.06 ---- 0.465
0.065 ---- 0.465
0.705 ---- 0.53
0.705 ---- 0.53
0.08 ---- 0.68
0.19 ---- 0.815
0.19 ---- 0.815
0.275 ---- 0.64
0.275 ---- 0.64
0.705 ---- 0.685
0.665 ---- 0.37
0.665 ---- 0.37
0.75 ---- 0.83
0.775 ---- 0.83
0.775 ---- 0.83
0.06 ---- 0.06
0.795 ---- 0.06
0.795 ---- 0.84
0.795 ---- 0.07
0.795 ---- 0.07
0.075 ---- 0.08
0.715 ---- 0.545
0.715 ---- 0.545
0.71 ---- 0.545
0.71 ---- 0.545
Log date Jan 20, 2013.

[vikram_d]

Originally Posted by Sankar

maybe because its still investigating the cause and would give the error after gathering sufficient evidence that its owner is trying to fool it

Most investigations are completed by the ECU in 3 hot cold cycles which I am sure your car has done in 800 kms. What are the readings of both the sensors now?

[Sankar]

Originally Posted by vikram_d

Most investigations are completed by the ECU in 3 hot cold cycles which I am sure your car has done in 800 kms. What are the readings of both the sensors now?

O2S1 -- O2S2 Voltage Reading with headers 7 no catcon. Log date March 10.

0 -- 0
0 -- 0
0.89 -- 0
0.86 -- 0
0.07 -- 0
0.78 -- 0
0.68 -- 0
0.75 -- 0
0.31 -- 0
0.01 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0.88 -- 0
0.85 -- 0
0.79 -- 0
0.11 -- 0
0.71 -- 0
0.21 -- 0
0.86 -- 0
0.82 -- 0
0.77 -- 0
0.77 -- 0
0.76 -- 0
0.81 -- 0
0.04 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0.88 -- 0
0.88 -- 0
0.16 -- 0
0.73 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0.09 -- 0
0.07 -- 0
0.73 -- 0
0.71 -- 0
0.73 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0.9 -- 0
0.88 -- 0
0.88 -- 0
0.58 -- 0
0.78 -- 0
0.72 -- 0
0.76 -- 0
0.85 -- 0
0.9 -- 0
0.09 -- 0
0.75 -- 0
0.1 -- 0
0.83 -- 0
0.76 -- 0
0.82 -- 0
0.77 -- 0
0.79 -- 0
0.77 -- 0
0.74 -- 0
0.11 -- 0
0.78 -- 0
0.81 -- 0
0.77 -- 0
0.09 -- 0
0.83 -- 0
0.6 -- 0
0.82 -- 0
0.82 -- 0
0.82 -- 0
0.78 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0.89 -- 0
0.87 -- 0
0.06 -- 0
0.82 -- 0
0.09 -- 0
0.77 -- 0
0.71 -- 0
0.77 -- 0
0.81 -- 0
0.82 -- 0
0.76 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0 -- 0
0.89 -- 0
0.89 -- 0
0.88 -- 0
0.88 -- 0
0.88 -- 0
0 -- 0
0.86 -- 0
0.06 -- 0
0.77 -- 0
0.87 -- 0
0 -- 0
0.86 -- 0
0.9 -- 0
0.89 -- 0
0.09 -- 0
0.77 -- 0
0.77 -- 0
0.77 -- 0
0.81 -- 0
0.71 -- 0
0.83 -- 0
0.83 -- 0
0.07 -- 0
0.07 -- 0
0 -- 0
0.89 -- 0
0.89 -- 0
0.88 -- 0
0.76 -- 0
0.52 -- 0
0.77 -- 0
0.78 -- 0
0.75 -- 0
0.22 -- 0
0.7 -- 0
0.16 -- 0
0.81 -- 0
0.78 -- 0
0.82 -- 0
0.81 -- 0
0.84 -- 0
0 -- 0
0.84 -- 0
0.86 -- 0
0.27 -- 0
0.77 -- 0
0.07 -- 0
0 -- 0
0 -- 0
0.01 -- 0
0.88 -- 0
0.47 -- 0
0.76 -- 0
0.75 -- 0.01
0.77 -- 0.01
0.79 -- 0.01
0.09 -- 0.01
0.83 -- 0.02
0.88 -- 0.01
0.86 -- 0.01
0.76 -- 0.01
0.74 -- 0.01
0.39 -- 0
0.81 -- 0
0.72 -- 0
0.79 -- 0.01
0.82 -- 0
0.56 -- 0
0.16 -- 0
0.78 -- 0
0.81 -- 0
0.78 -- 0
0.69 -- 0
0 -- 0
0 -- 0
0.88 -- 0
0.88 -- 0
0.72 -- 0
0.74 -- 0
0.76 -- 0
0.77 -- 0
0.78 -- 0
0.79 -- 0
0.7 -- 0
0.37 -- 0
0.77 -- 0
0.71 -- 0
0.81 -- 0
0.77 -- 0
0.77 -- 0
0.77 -- 0
0.77 -- 0
0.1 -- 0
0.72 -- 0
0.78 -- 0
0.79 -- 0
0.14 -- 0

I posted 200 rows of log here to show the duration its generating 0 volt compared to the few seconds its showing some very low voltage readings. Whenever the second O2 sensor is reading something its showing .01 to .02 volt which is waay below the normal range.

Primary sensor too shows 0 voltage sometimes, but that is normal and have logged similar with stock system too, and it sits before the catcon anyway.

Anyway i'll go home and check if the vehicle supports no activity code.

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(N, O - 3,205)