430 Bad new O2 sensors? Ignition Coils? Fabspeed Headers? Oh my!

I'm at wits end here, and thinking of returning everything to stock and selling the car. I'll admit I'm half venting and half seeking some advice on this post.

After installing the Fabspeed headers a couple of years ago I kept having issues with the Fabspeed provided extenders, followed by getting the O2 sensors stuck rich CEL, rightfully so, after the extenders repeatedly fell out of the converters even after multiple attempts at re-tightening by two different indy shops. Finally, I gave up and decided to send my ECU to Trev so I could not worry about CEL's resulting from the aftermarket headers in order to pass inspection, as well as to get some of the latest improvements that came with it.

Upon removing the damaged extenders, I decided it was a good time to replace the O2 sensors. The two on the drivers side were replaced by Bosch products ordered from Rock Auto. For some reason I keep getting the heater control circuit bank two errors (P0056 - Left rear o2 sensor circuit and P0051 - Left front O2 sensor circuit low). We've checked the grounds, the voltage on the ends, the wires themselves, and see no problems with it. Yet that error keeps coming up.

• Question 1: Has anyone received bad O2 sensors from Rock Auto, or really anywhere? Any ideas at what else could cause this? I'm considering buying a second set of new O2 sensors to try out, but obviously would hate to end up with extra O2 sensors if i'm wrong.

The third O2 sensors (passenger front), was not throwing a code at the time the left two were replaced and coding. However it was replaced by a Bosch part from Advanced Auto Parts after it was recommended to me to do both sides at the same time. Unfortunately, it's now reading P2196 - O2 signal biased/Stuck Rich, as well as P2270 - O2 sensor signal stuck lean (bank 1 sensor 2). At first I assumed this was related to the O2 sensors readings from the aftermarket headers, but I've read some other threads saying it could be the ignition coils? It's weird to me that the light came on after I installed a new one.

• Question 2: What are some things that would trigger a P2196 code on the passenger side front O2 sensors if the the sensor has been replaced.

Ironically, the rear, passenger side, O2 sensors I purchased from Ferrari of Austin is the only one not being flagged yet, which makes me wonder whether that's the issue (non-Ferrari part). However, there seem to be people here who have successfully used non Ferrari dealer parts as O2 sensors, and my part numbers match theirs.

Anyway, I don't get to drive it much as it is, and now I'm spending a lot more time than I'd like to trouble shooting. Most of my miles this year were driving around in circles in Austin trying to get see if the smog cycle check passed while we took things apart and put them back together multiple times attempting to address the O2 sensors issues. The local indy shop in Baton Rouge said they weren't sure where they'd go from here, and I won't have the time or proximity to better experienced Ferrari indy's or dealers until later this year. Hopefully the Fchat brain trust can provide some guidance. I really don't want to go back to stock as the car sounds and drives amazing otherwise, it's just hard and frustrating to troubleshoot something without knowing where the baseline is.

 

The tune is already done, that’s why I think it’s the o2 sensors themselves.

Yep, well we’re probably going to find out for certain because all I can think of is that I will have to try the OEM parts. Or at least buy them from Maserati? Which sucks because the front O2 sensors were something like $450 each from Ferrari versus $95-140 without the Ferrari name. So $900 vs $300. The rear ones are only 2x. Thing is I can see the left ones having issues, but the non-Ferrari on the right has a different error suggesting a different issue.

 

That was the idea. Trev is well known on the forum and has a good reputation. I told him what whatever the tune was, it needed to pass California inspection in case I ever sold it to someone there. I wanted to feel confident I wouldn’t have to worry about that when selling the car. Unfortunately I was having the o2 sensor issue while I sent the Ecu off so I haven’t baselined the car yet. However my understanding is that it should pass CA with aftermarket headers.

 

Mine is a 2005. I thought challenge headers were considered “stock”, I wouldn’t expect them to trigger a CEL, but I could be wrong.

 

Hi John, there are two separate issues going on. The Fabspeed side of it was the extenders never stayed on, and had to be sent back to be repeatedly tightened, ultimately the thread got ruined and we had to re-tap one of the catalytic converters. We got lucky because for a minute there we were concerned we'd have to replace it if we couldn't successfully tap the hole. I'm attaching pics. The headers, blankets, and extenders were initially installed by Josh at Exotic Performance in Austin. They worked while they stayed in place and I did not have CEL issues. It was that they wouldn't stay on that was causing the problem. They would vibrate and come loose, so I took it back to him one or twice to fix, then Ferrari of Austin where they recommended I remove and return to stock because they were concerned it would cause damage to the catalytic, before I left to Baton Rouge. While in in BR, they came loose again, and this time I took them to Vinnie's Exotics to get them tightened a last time to buy some time in deciding what to do. After that there was no way to keep them tight, they would literally vibrate off during a single drfive and of course after that the CEL's stayed on. That's what kicked off my journey with the O2 sensors. I may take you up on your offer some fresh ones, but I think that part of it has been addressed, and I'm not sure if it's a permanent fix based on what I just went through. After the money I spent trouble shooting this via shops, I've been doing the work with my dad on the O2 sensors. At this point I've gotten pretty proficient at taking it apart and putting it back together, also my dad does mechanic work, for the more complex aspects that may arise.

After I realized the extenders weren't going to work, I forked out the money to permanently fix the problem via the ECU. I'm assuming that's not the cause of my current O2 issues. This second part is most likely that for whatever reason the two O2 sensors (drivers side) I got from Rock Auto are showing a heater circuit fault which doesn't make much sense. Then I do have the one stuck rich on the passenger side, without the extenders, so I need to trouble shoot that.

 

Update: Not sure what would have lead to the following blown fuses or whether my attempts to circumvent the O2 extenders contributed, but replacing these sensors seem to have removed the CEL. Picking up the car from the shop, and will update if issues return.