I had replaced the Catalytic converters/exhaust pipes on my 06STR because when I got the car somebody had welded the cats in and it looked restrictive to me like it knocked down going into the cats. I bought some pacesetter or Devico cats that are assembled onto the head pipe coming off the exhaust manifolds

I’ve been having recurring faults for Cadillac efficiency P0430 very rarely PO420. I’ve done so many different things to try to cure it but keep coming back.

I have bad cats or converters. It just aren’t up to the task and I say that because when I look at the output from the sensor to O2 sensors, it doesn’t look like much is happening compared to the sensor one O2 sensors

Site did some live monitoring using SDD version 1.31 and I noticed some weirdness maybe you can figure it out. Some question about the pids that they allow you to look at.

I noticed they were two pids for fuel pressure. When I was monitoring the first one that was listed, I was showing only 43.5 psi to 47 psi. The other pid is label exactly the same “fuel pressure pressure (Pcm)”. This one measured between 50 and 55 psi. what the heck is the first one for?

I looked at long-term fuel trim. Bank one measured 1.56% solid. B2 started out measuring around 3.5% and slowly increased over the next 45 minutes or so to 6.25%. P0430 is for bank two so possibly related I thought long-term fuel trims only adjust if you have high short term fuel trims, but I’m not having that. But I am having a little offset on the bank two sensor when I look at the current fot sensor1

So for my O2 sensor current bank, one sensor one it measures 0uA to -70uA. B2 sensor one current shows 20uA to -70uA so bank 2 has a little bit bigger swing than the bank one sensor. Those signals look like a triangle wave and bank 1 and 2 appeared to be in phase.

The short term fuel trim for both bank one and bank2 was between 2% and -4% Both singles kinda look like a digitized sine wave

Short term, fuel trim for bank one sensor two measured exactly the same as bank two sensor two. we both measured -1.56% to 1.56% and looks like a square wave

I looked at universal exhaust gas, oxygen heater, pre-cat bank, one measured 61.5 ms to 62.5 ms but bank two measured 62.9 ms to 70 ms. What is the pid looking at? It’s obviously a timing measurement but I don’t know what it represents other than possibly the time it takes to respond to a change in mixture?

I looked at the map PSI and it was measuring 4.93 psi to 5.07 psi but the signal had no bikes on it in the positive direction like _____|_|____|_|_||__

map voltage Measured .95 V steady

And the maf sensor also looked weird it would be steady state at 4 V but then jump up to 5 V and we stay for a while but then slowly you’d see negative noise bikes that would increase in frequency until the signal drop back down to 4 V with the series of positive spikes. Not sure what’s going on there, but I did clean the sensor and reinstall it but I haven’t taken the measurements on it.

I also looked at the intake, variable valve, camshaft timing and I had a difference between bank one and two. Bank one measured between 38.8° to 38.9°, whereas to measured 44.2° to 44.3° I would’ve thought they would be similar, but they were different and I don’t know if that matters

I’ve uploaded pictures of my notes as well as some of the signals that I measured so you can see what I saw.

Can anybody tell me whether or not signal for stft sensor two looks correct or should it be flat showing catalyst action?

Or any ideas why my O2 current readings for sensor one has the range from 20 to -70uA versus bank 10 to 70uA

Should the intake variable valve, camshaft, timing numbers be the same between bank and bank two? Finally what is the difference between the two fuel pressure Pids?

 

More screenshots

 

And finally the stft for sensor two and others

 

Whats the difference between the fuel rail pids?

 

atmospheric vs absolute fuel pressure. frp sensor is hooked to manifold reference, vacuum assists and boost fights effective fuel pressure

as for the 420/430 don’t question it, cat efficiency algorithms are extremely complex and 100% accurate just go get it tuned out

 

tuning it out is something ive not considered. Im really getting tired of it

 

I have an 06 str and the variable timing numbers are the same as yours and my car runs great no codes. I always wondered why they would be so different but just figure that is just the way it is. Now that i see yours are the same i am sure of it

 

it’s good information to know! Whenever I see differences between something I think should be similar it usually points me in the direction of a possible problem but I guess in this case, it’s just typical