P0420 & P0430 codes at same time with new supersprint cats

[mcfreid]

OP, are you running with a tune or still on the stock file?

stock

[CarbonBlkM3]

Why pay $$$$ for a premium exhaust only to have a cheap fix? Seems like we’re getting junk lately from SS??

Incase you aren't familiar, Supersprint Section 1 uses 200CPI Catalysts, that's basically very minimal restriction when you think about it. Even with the Post 02 sensors extended you still throw a chance on getting a code. All you're doing with the cheap fix is desensitizing the 02 sensors so they pick up less emissions.

[CarbonBlkM3]

I got my SS full exhaust work done way back in 2007, so it's been a while. If I recall there wasn't enough factory wiring to simply relocate them to the Supersprint catalysts and the wiring needed to be extended. Unless later models came with longer 02 wiring from the factory?

[mcfreid]

I got my SS full exhaust work done way back in 2007, so it's been a while. If I recall there wasn't enough factory wiring to simply relocate them to the Supersprint catalysts and the wiring needed to be extended. Unless later models came with longer 02 wiring from the factory?

Factory wiring for me was long enough if you routed through the driver-side transmission tunnel instead of the passenger side.

[Tbonem3]

I was gonna mention that. Re-routing the wires, in order to reach, wouldn't increase resistance and affect readings.

[mcfreid]

Cleared the codes again and so far it hasn't come back. Seems to take some time for the ec2 to log the fault. I'm still not sure if it's because of the slightly out of spec voltage ranges for the post cat sensors, or something is actually wrong in certain conditions.

Anyone else have any thoughts or experience here?

Strongly prefer not having to put in some spacers or a defouler as a hack for cats which should be plug and play.

[CarbonBlkM3]

Cleared the codes again and so far it hasn't come back. Seems to take some time for the ec2 to log the fault. I'm still not sure if it's because of the slightly out of spec voltage ranges for the post cat sensors, or something is actually wrong in certain conditions.

Anyone else have any thoughts or experience here?

Strongly prefer not having to put in some spacers or a defouler as a hack for cats which should be plug and play.

Why are you strongly opposed to it? Your driving yourself crazy fiddling with codes & faults meanwhile a $5.00 fix may alleviate all that aggravation. All you're doing with the defouler is limiting the sensitivity to the 02 sensor by not letting the probe extend too far inside the post catalyst. 🤷♂️

[repoman89]

Who ever said race cats should be plug and play? The answer to the thread has been posted multiple times. Turn off the codes or go back to stock.

[Tbonem3]

Why are you strongly opposed to it? Your driving yourself crazy fiddling with codes & faults meanwhile a $5.00 fix may alleviate all that aggravation. All you're doing with the defouler is limiting the sensitivity to the 02 sensor by not letting the probe extend too far inside the post catalyst. 🤷♂️

You can even do it via coding, if you really don't like the physical presence of the extenders.

[mcfreid]

Quick update: I've reset the codes some time back and so far they haven't come on again. Not sure if it was a fluke, or maybe temperature sensitive. Still perplex about the post cats cycling intermittently voltages on a warm idle instead of stable...

Just in case it comes back on, coding out the post cat o2's is not an option for NJ emissions check. Was going to order the spark plug non-foulers - though I'm not sure if they'll fit into the drivetrain tunnel with the over-sized section 1.

1. Has anyone installed spark plug non-foulers on the over-sized supersprint section 1 (with cats)? From what I recall, there wasn't much room to fit the spark plugs and wiring.

2. Also reading more into disabling the EGT (which I have not done) in https://nam3forum.com/forums/forum/m...on-egt-changes - is it possible cold start / EGT could be throwing off the voltages with HJS cats?

[Casa de Mesa]

Simple two step fix. 1) code the post cat 02 sensors out. 2) drive.

I followed the two step fix. Worked like a charm.

Jersey checks to see if you're rear O2s are active? How's would they know?

[mcfreid]

I followed the two step fix. Worked like a charm.

Jersey checks to see if you're rear O2s are active? How's would they know?

They plug into the OBD2 and the car needs to respond back that the cats are active/ready. If you code out the sensors, the car won't respond to their scan.

[Mike RT4]

It's the norm for these cats, I get the same thing. The DME is expecting a specific flow disparity from the front to rear O2 sensors, the higher flow nature of the HJS cats means that it doesn't see what it is programmed to see, so throws up the code.

I also only get the issue with light pottering around (I believe that this is probably becuase this is when the DME is in closed loop fuelling and so is relying on the inputs of the O2 sensors to do the fuel trimming, hence it's getting its knickers in a twist that the figures aren't what it is expecting due to the increased flow of the upgraded cats,

[mcfreid]

Hmm, Obioban how did you get around this? I believe your state has a smog check as well, no?

[Obioban]

You can code them down or code them off. If you code them down (still requires them to be installed), no lights and good to go for plug in obd2.

That said, my car is a “classic” now, so I don’t have to deal with any of that anymore.