[RotarySwingGolf]

I bought my '98 355 this week and decided that after 4 days of ownership, it was time to start modifying ;-). I knew from the last major that was done this year before I bought the car that the aftermarket cats that were on it were failing but the last owner decided to hold off on replacing as they were still ok at the moment. I'm swapping them out for track pipes and getting rid of the Tubi exhaust for a Capristo (anyone looking for a Tubi?!).

After getting the expected CEL that I was waiting on for the ailing cats after putting a couple hundred miles on the car, I pulled the codes and got P0134 that triggered the CEL and P0410 as pending. The P0410 was from the typical blown fuse. Swapped it out and now I can hear the annoying fan on cold starts so that should get rid of that code. My issue now is that, as I understand it, the heater for the O2 senors is on that same fuse. So I'm wondering if the Bank 1 Sensor 1 P0134 error I'm getting is just related to the cat failing or also from the P0410 and the fuse being blown. Long story short, should I replace the O2 sensor while I have everything apart or is it likely fine?

Car has 17,500 miles and Fabspeed headers. I don't know why the original cats were replaced nor what brand. After pulling them off the car last night there is no branding on them whatsoever, only thing I can tell is that they are made of stainless. The car was owned by a collector for its entire life before me and always serviced at a Ferrari dealership, so it's a bit of a mystery on these cats, but I'm scrapping them anyway.

[RotarySwingGolf]

FWIW, I decided to just replace both O2 sensors and be done with it. Ordered from Amazon for $75 each, so it's really not worth worrying about.

If anyone reads this though, I'm going to try the "Big Daddies" or whatever they're called O2 sensor simulator for the rear sensors to try avoid the CEL running track pipes, anyone tried these? O2 Simulator Mini Cat Cel Fix

[ALEX A]

Hi , do not waste money on the simulators , they do not work.
You have two options. First test pipes and upgrade software for the engine so you do not get a check engine light .Second install hyper flow cats so the cars run properly.
i have done many cars and these are your only options.
Let me know what happens.
If you need any help , please feel free to call or email me.
Alex.

[RotarySwingGolf]

Originally Posted by ALEX A

Hi , do not waste money on the simulators , they do not work.
You have two options. First test pipes and upgrade software for the engine so you do not get a check engine light .Second install hyper flow cats so the cars run properly.
i have done many cars and these are your only options.
Let me know what happens.
If you need any help , please feel free to call or email me.
Alex.

Hi Alex, it looks like I'll probably be throwing a CEL soon, got a pending 1445 and 1449. What are the options for the software upgrade?

[ALEX A]

To reprogram an ECU to Euro version which would give you also more horse power . The cost would be around $3000.00 . This is the proper software from ferrari italy using your ECU.You can also program the ECU for no cats if you would like to remove them. You also can remove the upper exhaust valve.The car would sound amazing. I have done a few. If you buy hyper flow cats . I think they cost around $2290.00 for the set and about 3 hours to install.Either way, this will solve your problem. You also may need 1 or more o2 sensor.If they are aging.
Alex.

[RotarySwingGolf]

Originally Posted by ALEX A

To reprogram an ECU to Euro version which would give you also more horse power . The cost would be around $3000.00 . This is the proper software from ferrari italy using your ECU.You can also program the ECU for no cats if you would like to remove them. You also can remove the upper exhaust valve.The car would sound amazing. I have done a few. If you buy hyper flow cats . I think they cost around $2290.00 for the set and about 3 hours to install.Either way, this will solve your problem. You also may need 1 or more o2 sensor.If they are aging.
Alex.

I've done a bit of research on the ECU upgrades out there, the only one I'm familiar with is the Fabspeed and the reviews have been paltry at best and that's at $2k. For $3k, I'd need to see a lot of documented dyno's and reviews. I have Fabspeed headers already, so those will be staying. As for removing the bypass valve, wouldn't that then trigger P1448?

O2 sensors are new. What I'm really looking for is just an ECU flash to widen the O2 sensor sensitivity parameters rather than a complete fuel mapping, etc. redo. I'm not looking for performance in this car, just to get rid of the pending codes and CEL's.