Hi, Tuner Crew. Thanks in advance for your knowledge and for taking the time to take a look. I'm hoping you can make heads or tails from what's happened to my Fusion following a tune(s) from a competitor. Aside from that mod, the previous owned had installed a GFB diverter valve, it's the T9354 if I'm not mistaken, and that was it. No other mods.
- 1 Bought the car in SLC, UT with 7k miles and drove it home 10 hours to NW Montana with no issues.
- 2 Purchased (2) custom tunes from a fellow, a 91 octane tune and a 110 tune, along with a colder set of iridium plugs and an SCT BDX tuner. Tuner doesn't have an entry for my car, so I was told to use "Ford Gas 2012(I think)-newer" gauge setup.
- 3 Installed the 93 tune and started throwing the P0420 a day later. Installed the plugs, gapped at .028. Still throws the code.
- 4 Returned to stock via the BDX tuner. Still throws the code.
- 5 Tried the 110 tune, using a half tank of 110 fuel. Threw the code.
- 6 Opened a ticket with SCT, mentioning that the tuner doesn't always power up with the vehicle (it's since become worse and actually powers off momentarily while driving, occasionally. They said it could be the cable and that they'd send me a new one. Never did. Then, they said that my ECU is the culprit because it/they stop communicating with tuners at random times/go to sleep.
- 7 Returned to stock tune and visited the Ford dealership. Dealer said the tune was still in it and couldn't warranty anything as long as it was. They checked sensors and cats and found nothing wrong. Also tested injectors for leaks. I went home and reperformed the 93 tune, then returned it to stock after updating the tuner per SCT's recommendations. Returned to the dealer, who then said my ECU was showing as blank to their reader. Car still runs, still throws the code, but they can't talk to it now.
- 8 So here I sit with a CEL that disables my remote start and a car that smells of raw gas out the tailpipes. The crazy thing is that I drove to Portland and had the code while I was at high elevation, but didn't get it at all while around sea level and using their 92 octane gas (91 tuned). As soon as I came home, the code returned.
I feel like the dealer missed something when they tested those O2 sensors, but that's just a hunch. Got any other ideas?