I need someone to help me with a vacuum problem

[b4black]

Running lean is causing both codes. The converter is design to work with normal emissions. Lean exhaust can throw downstream sensor out of threshold range.

Don't keep screwing around with the downstream sensor. Fix the real problem and both will go away.

 

[b4black]

2003 Buick Park Avenue Ultra - Built trans / SD headers / FWI / Catless

Wait, you don't have a converter?

 

[slowchevy]

Future modz, currently running a zzp downpipe with spun convertor

 

[Lord Tin Foilhat]

Lmfao you don't even put real mods in your sig.....wow

 

[b4black]

Future modz, currently running a zzp downpipe with spun convertor

OK, I'm adding a flux capacitor to my signature.

What exactly is a 'spun' converter?

 

[ktraver97ss]

"High flow" I believe.

Its amazing the assbackwardsness of how s00ls does shit. If you would have got a tune like we all told you in the beginning before even doing the cat you would not be having any of these issues, would have passed emissions, and would have spent far less money.


<---waiting for "to each his own" and "i like to be unique" when in reality you just make bad choices.

 

[Yaj Yak]

HE IS LEARNING KTRAVERS. LET HIM BE. HE WANTS TO LEARRRRRRRN

 

[ktraver97ss]

Hell, we all make our stupid decisions, but Ill be the first to admit when I go full retard. Like I did when I replaced my trans when all I needed was to gut a cat out. :lmao:

 

[DanJ]

Even with a brand new high flow cat, the rear O2 can set a below thresh hold or whatever code. Mine went off within days of putting a magnaflow cat in. If you had the same cat, DP, and rear O2 sim functioning fine before you took it apart, it's only logical to assume something you touched is the culprit.

 

[slowchevy]

Lmfao you don't even put real mods in your sig.....wow

they're real. they're not on the car yet. still counts. if you have no valuable information to post, stay the fuck out of my thread. i don't shit on threads where you're asking for help. dick face.

OK, I'm adding a flux capacitor to my signature.

What exactly is a 'spun' converter?

They start with the core and then shape the pipe around it vs putting two halves together with the core inside. That's what my ZZP downpipe came with opposed to a normal one. First time I'd seen one so I did some research.

from teh googlez

The Magnaflow spun catalytic converter is a compact catalytic converter design for use in tight places, such as on street rods or for custom car applications. Magnaflow fabricates each converter body from a single CNC-formed and laser-welded tubular section, which is then spun into a 4'' round converter body shape. Each converter is literally manufactured around the ceramic catalyst, securely tucked inside, and necks down to thicker gauge material at the inlet/outlet for maximum durability. Converters contain the properly loaded ceramic catalyst for optimum cfm.

"High flow" I believe.

Its amazing the assbackwardsness of how s00ls does shit. If you would have got a tune like we all told you in the beginning before even doing the cat you would not be having any of these issues, would have passed emissions, and would have spent far less money.


<---waiting for "to each his own" and "i like to be unique" when in reality you just make bad choices.

It happens.

 

[slowchevy]

Even with a brand new high flow cat, the rear O2 can set a below thresh hold or whatever code. Mine went off within days of putting a magnaflow cat in. If you had the same cat, DP, and rear O2 sim functioning fine before you took it apart, it's only logical to assume something you touched is the culprit.

This code originally happened in december after I had the new downpipe installed. installed o2 sim and it had a lean code, so when I put the o2 back in the pipe, this code came back. So I know it's the high flow cat for sure setting the code. It's tune time.

 

[Angus]

So just to clarify, is the lean code gone now and you just have the threshold code?

 

[slowchevy]

precisely.

 

[b4black]

Read the fine print on ZZP downpipes

***IMPORTANT information concerning High Flow Catalytic converters*******
The downpipes we sell come with a high performance converter. It is OBD2 compliant but it is on the very edge of being so. The PO 420 code is set when the rear bank O2 sensor PCM thinks that the converter is not doing a good enough job. Because the stock cat is so thick and dense, it can still function when the tune is off or it gets old. An error in tuning, running too rich, having too cold of a Tstat, too cold of plugs, or an old primary O2 sensor can all affect the engine enough to set a code when using the cat.

The last sentance is key. If something is off, the threshold code (P0420) will be set. The simulator addressed the P0420 code and exposed the lean condition (which got worse with the addition of the free flowing downpipe).


If this doesn't make sense, then throw in the towel and put the stock DP back on.

 

[slowchevy]

Stock downpipe is long gone, cat melted down. I have a new front o2 sensor I'll install and see if it helps any with the SIM in place.

 

[slowchevy]

Car has a 180º NON DRILLED tstat and AL104s if that's relevant

 

[1quick]

so you only have the p0420 code now?

 

[slowchevy]

Yup. Pending what happens tomorrow, a buddy is going to try and turn off the rear o2 and see what happens