A Weird but Understandable (I Think) Issue with my Subaru
I'll try and lay this out as best as I can. By the way, if anyone has any thoughts, I'd love to hear them.
Problem: My car (2005 STi) gets an intermittent P0420. Sometimes it doesn't show up for a while.
Specifics: IAG Case Halves, built engine by FAST of West Chester with a turbo kit from Full-Race (I started the build a long time ago, and FAST completed it for me (they are A+ I also don't want to bring them this problem because I don't feel like giving them an emissions related issue this day and age.)
Even though the build was completed JUST before Greenspeed, we added a GESI cat JUST AFTER the downpipe so we didn't ruin the coating of the downpipe, and because we wanted to be nice to the environment. I know the location is the problem. O2 Sensor is just after that. This happens on 93 octane, or e85.
New o2 sensor too.
Happens When: After driving for 10 minutes: if I'm on the high way cruising (target speed of 60mph) and I'm not on, or can't use, Cruise Control (because of traffic), and I have some on / off throttle moments changing speed and going from 50-55 back to 60, or 65 - 70 back to 60, the check engine light will come on with a P0420 DTC.
Doesn't Happen: (This is anecdotal - I don't daily the car) If as soon as oil temp has come up, I get on it, then eventually get to my normal cruise control speed. No CEL / DTC.
Or, if I'm able to - from the cold START OF THE DRIVE - actually just use cruise control WITHOUT interruption, no CEL / DTC.
Or, if the car is still warm from driving to a location / driving all day / after autocross, etc.
My Request: I feel like the difficulty is that the cat just needs to warm up because of its location. Is that logic right? If it is, what's the best way to do that, in anyone's opinion?
Joke: In troubleshooting I thought if only I could put more air in the catalytic converter during startup, then realized I invented the secondary air injection pump, which has already been invented, and many people do what they can to disable it when adding after market stuff.
2005 STi Build Sheet
Problem: My car (2005 STi) gets an intermittent P0420. Sometimes it doesn't show up for a while.
Specifics: IAG Case Halves, built engine by FAST of West Chester with a turbo kit from Full-Race (I started the build a long time ago, and FAST completed it for me (they are A+ I also don't want to bring them this problem because I don't feel like giving them an emissions related issue this day and age.)
Even though the build was completed JUST before Greenspeed, we added a GESI cat JUST AFTER the downpipe so we didn't ruin the coating of the downpipe, and because we wanted to be nice to the environment. I know the location is the problem. O2 Sensor is just after that. This happens on 93 octane, or e85.
New o2 sensor too.
Happens When: After driving for 10 minutes: if I'm on the high way cruising (target speed of 60mph) and I'm not on, or can't use, Cruise Control (because of traffic), and I have some on / off throttle moments changing speed and going from 50-55 back to 60, or 65 - 70 back to 60, the check engine light will come on with a P0420 DTC.
Doesn't Happen: (This is anecdotal - I don't daily the car) If as soon as oil temp has come up, I get on it, then eventually get to my normal cruise control speed. No CEL / DTC.
Or, if I'm able to - from the cold START OF THE DRIVE - actually just use cruise control WITHOUT interruption, no CEL / DTC.
Or, if the car is still warm from driving to a location / driving all day / after autocross, etc.
My Request: I feel like the difficulty is that the cat just needs to warm up because of its location. Is that logic right? If it is, what's the best way to do that, in anyone's opinion?
Joke: In troubleshooting I thought if only I could put more air in the catalytic converter during startup, then realized I invented the secondary air injection pump, which has already been invented, and many people do what they can to disable it when adding after market stuff.
2005 STi Build Sheet
- IAG Stage 3 Closed DeckIAG Firelock Rings
- 99.75mm Bore
- ARP case bolts
- Short Block (inside case)Manley Crank
- Pauter Rods
- JE Pistons (coated)
- King bearings
- Killer B oil pan and pickup tube
- Subaru 11 mm oil pump
- Subaru Water Pump
- Heads
- GSC springs, retainers, and valves
- BC 272 Cams
- IAG 14 mm head studs
- TurboGarret GT3582R T4 Divided 1.06AR 3" V Band outlet
- Full Race Subaru STI Dumptubes for Twin Scroll Kit
- MVS Wastegate 38mm Black w/ Full-Race logo
- Full-Race Reverse Intake Manifold Kit
- Blow Off Valve 10 PSI spring
- Ceramic Coating on downpipe, up pipe, lower manifold, and turbine housing
- Fuel
- Radium Twin Fuel Pump hanger with 2 Walbro 450s
- IAG rails and ID 1700 injectors on flex fuel
- Hobbs switch at 16 PSI for 2nd pump activation
- iWire fuel pump controller
- Cobb flex fuel kit
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