Downpipe Related, ways to prevent CEL?

[Bakis]

Ok guy's for the time being im not going to purchase a Downpipe, im just going to try and modify the CATs in the Standard one.

Correct me if im wrong but the second CAT (further away from Turbo) isn't monitered by a O2 Sensor, and if i remove with a Race Pipe shouldn't cause a CEL?

I know 'grey alex' premhk has done this and he hasn't got a CEL so im sure that well work.

As for the First Cat, i dont wanna run catless but if i get an exhuast shop to replace with a 100CPI or a 150CPI car what are the risks of receiving a CEL? I know the BM downpipes has a 100CPI CAT at the end of it and that guaranteed no CEL.

Question is what do i have to do if i want to replace the first cat with a better flowing one and not receive a CEL?

All help is appreciated

[Reedy]

You're right about the second cat not being monitored, but from all reports these days the new DP upgrades have fixed the CEL issue, it was only the early ones that caused problems. New ones re use the sensor and if installed properly, shouldnt give a CEL.

[2XS]

Ok guy's for the time being im not going to purchase a Downpipe, im just going to try and modify the CATs in the Standard one.

Correct me if im wrong but the second CAT (further away from Turbo) isn't monitered by a O2 Sensor, and if i remove with a Race Pipe shouldn't cause a CEL?

I know 'grey alex' premhk has done this and he hasn't got a CEL so im sure that well work.

As for the First Cat, i dont wanna run catless but if i get an exhuast shop to replace with a 100CPI or a 150CPI car what are the risks of receiving a CEL? I know the BM downpipes has a 100CPI CAT at the end of it and that guaranteed no CEL.

Question is what do i have to do if i want to replace the first cat with a better flowing one and not receive a CEL?

All help is appreciated

Have the first cat removed completely, good luck finding any exhaust shop to do that for a reasonable price,
Next, have the 2nd Cat replaced with a quality 200 Cpi one,
Last, have the 2nd O2 sensor extended behind the now first Cat.

Pending any issues, You can use an O2 sensor extension.



NOTE: 100 Cpi cats are illegal Aust wide.
NOTE: Removing 2 cats and replaceing it with 1 item is illegal in NSW (Pending an engineers cert.) Vic is similar in Laws to NSW.
NOTE: You may even need a Euro 4 cat to get away with 1 Cat in NSW

[Bakis]

Thanks troy the legal thing doesn't fuss me much but ill see how I go. Just to put it out there if I wanted the 100cpi cat would there be any issues with this over a 200cpi? Or is the flow difference not even worth it?

I'll find prices then way up options thanks guys

[2XS]

If you are still running the std DP, but just replacing the cat, the benefits would be lost everywhere else in the setup.

I highly doubt you would see any gains in performance getting a 100 cpi over a 200 cpi in a std to mildly modded MPS.

Gees, a highly modded XR6 turbo only sees +2-3Kw @ wheels from 200 cpi to no Cat at all.

[Yeldarb]

Well, I still have CEL's with my BM DP. I love it, don't get me wrong, just a bit peeved nothing seems to have been done about it.

The CEL seems to give me a very rich mixture. My tail pipes are always black and I wash the car weekly. The car sounds different too, probably the extra fuel burning off or something.

Go the DP man. You will not regret it.

[Bakis]

If you are still running the std DP, but just replacing the cat, the benefits would be lost everywhere else in the setup.

I highly doubt you would see any gains in performance getting a 100 cpi over a 200 cpi in a std to mildly modded MPS.

Gees, a highly modded XR6 turbo only sees +2-3Kw @ wheels from 200 cpi to no Cat at all.

Thank's Troy cleared the waters for me . I think i'll copy premhk and what he did he made about 75% of the gains from gutting a cat of which ppl have made from installing a DP/

This is the course of action atm cause i finish uni at the end of next year and might be going on a holiday after it with mates and depending where on the east coast might either drop in at 2XS or BM for a downpipe .

[Nirvandan]

might either drop in at 2XS or BM for a downpipe .

Its a no brainer, 2XS.

[Reedy]

Time to revive this thread.

I have had a Cp-e DP for 9 months now and got my first cat related CEL (P0421 Warm up cat efficiency below threshold)

Scenario:
2010 Gen II MPS
Cp-e DP
ECUTEK tuned
Car had been tracked the day before
CEL came on shortly after filling up on the highway on the way home from brisbane.
TH installed an O2 sensor extension and cleared the code, but it came back again the day after.

Possible causes:
Track day? If anything is going to cause problems it's tracking the car. I have tracked it a handfull of times before without any issues. Wth the amount of smoke my car blows it wouldnt surprise me if the CAT has become fouled.

Dodgy batch of fuel? It came up after I filled up, coincedence? possible? I have since finished off that tank and filled up again so will see what happens once I clear this second code.

CAT is blocked/fouled? I read somewhere that you can pop the car in neutral and run it at 4000rpm for a minute solid to burn off built up carbon in the cat? is this internet bullshit or can it actually help? If not will I need to get a new cat to fix this issue? Any other way of renewing a CAT?

[Cton]

It would be a huge pain in the ass to change the cat on the cp-e downpipe. I know Matt had a Cpe downpipe that had a cat that had crapped itself.
It's strange to get the cat efficiency code with the Cp-e, being that the sensor is after the cat.
Maybe it's crapped itself totally? I guess there is no way find out without removing the DP though.

[SarcasticOne]

Doesn't the cpe one have a removable cat?

[Reedy]

CP-e one is built into the DP.

Can they give my zorst an endoscopy to take a look at the cat?

Far as I knew there was a sensor before and after the cat and the ECU just compares the 2 to make sure the Cat is working.

[Caffeine Fiend]

From what I can tell, the default cp-e DP has two sensor bungs. One for the factory O2 sensor, the other for an optional wideband sensor.

Both are BEFORE the cat, in the bellmouth (see image below)

You can get a third bung welded at time of order for an additional wideband. Not sure where the positioning of that would be though. But unless you specified it at order, it should only have the two.





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[RedDjinn]

CP-e one is built into the DP.

Can they give my zorst an endoscopy to take a look at the cat?

Far as I knew there was a sensor before and after the cat and the ECU just compares the 2 to make sure the Cat is working.

Yes, all you have to do is extend the 2nd co2 sensor away from the pipe. you can buy these i think ebay? i know street unit sold them. It tricks the ecu cuz when moving the sensor out of teh flow of the exhaust, thinks the cats working (restricting flow) this will stop the cel

[Reedy]

That's exactly what tunehouse installed, the CEL came back tho.

(I haven't actually had a chance to read the latest CEL actually, so it could be something completely different this time. Chances are it's the same problem tho.)

[Cton]

^ that picture is of a DP with a wideband, that dp would have 3 sensors. One of the top ones before cat for an o2 sensor, one for a afr gauge, and it will also have one down at the cat. The second one at the top is the optional one.
The cat on the Cpe is gonna be pretty hard to get on the car I'd say, as it's pretty far up the DP.

---------- Post added at 11:03 AM ---------- Previous post was at 11:00 AM ----------

You have no reason to need to extend the sensor out. Your sensor is located in the correct position. If you pull it out on a extender, you prob get the p2096 code which caused by low voltage as it's out from the stream, your better off with the cat code than p2096. As the cat code won't make the car run richer.
First Gen works very different to Gen 2s

[Yeldarb]

Troy moved my 2nd OEM sensor downstream of the his newly installed 200cell cat. Took a couple of resets but I haven't had a P2096 for 6 months!

Did get a P0421???, after a hard session. Cleared it, never seen since!

[Reedy]

The first one was P0421, I havent read what the second one is yet but chances are it will be the same. Altho since they installed the sensor extension there's a chance it might have changed things.

[Jrbris]

I got that cel light once and it's never returned. i have put it down to crappy fuel also as other than that nothing was changed and this was a few months after the 3" system was installed.

[Reedy]

So from the sounds of it the O2 extension was probably the wrong thing to fit, and there's a good chance that has turned my harmless CEL into a harmful one. Turns out the standard fix for the Gen 1 isn't appropriate for the Gen 2. I need to get this latest code read asap.

Is this extension easily removed without trashing the sensor? I'm not too keen on taking it in and spending $100 on labor for something that I can probably do myself in 2 minutes.