Hey all - long time lurker but first post here. Unfortunately something happened to my '13 Sonic 1.4 turbo, 6 speed w/ 134k mi on it. Hoping you can help me figure out what to do next to diagnose
Symptoms:
Things I've checked already:
Turbo still sounds like it spools up fine, no strange sounds. Changed the oil after this happened and didn't notice anything bad in the drain pan. No CEL (there was the p0420 on at the time this happened, since went off). No foamy oil or bubbles in antifreeze.
I've had the p0420 cat efficiency code off and on for past year or two.
Puzzled on what to do next to diagnose. Possible cat is plugged? Blew a valve seat or gasket? Turbo on its way out? Fried a piston? Open to any ideas. Should I do a compression test?
I tried logging some data with Torque app and it will still hit ~16 psi of boost if I stomp on it in a high gear. But it seems delayed to spool up. Basically 3rd gear feels like 4th and so on. Vaccuum at -18/19 idle and -22/23 braking. No boost leaks or vacuum leaks anywhere I can tell. Engine sounds smooth no ticks.
Recent maintenance:
Changed plugs w/in past 10-15k miles
Mobil1 synthetic oil every 5-7k mi
Replaced t-stat, coolant outlet housing, coolant resevoir.
"Mods":
MPFab intake
Bypass the bypass
Ported IM w/ aftermarket external check valve mod.
These have all been in place and fine since I bought the car @ 100k mi
Curious what you guys think. Love the little car. Going to park it now until I can get this figured out. Hopefully you can give me some guidance short of swapping out the whole powertrain or blindly replacing parts....
Symptoms:
- Noticeable loss of low end power/torque
- Runs rough for a couple seconds on startup
- Hesitation and surging between 3-4k rpm
Things I've checked already:
Turbo still sounds like it spools up fine, no strange sounds. Changed the oil after this happened and didn't notice anything bad in the drain pan. No CEL (there was the p0420 on at the time this happened, since went off). No foamy oil or bubbles in antifreeze.
I've had the p0420 cat efficiency code off and on for past year or two.
Puzzled on what to do next to diagnose. Possible cat is plugged? Blew a valve seat or gasket? Turbo on its way out? Fried a piston? Open to any ideas. Should I do a compression test?
I tried logging some data with Torque app and it will still hit ~16 psi of boost if I stomp on it in a high gear. But it seems delayed to spool up. Basically 3rd gear feels like 4th and so on. Vaccuum at -18/19 idle and -22/23 braking. No boost leaks or vacuum leaks anywhere I can tell. Engine sounds smooth no ticks.
Recent maintenance:
Changed plugs w/in past 10-15k miles
Mobil1 synthetic oil every 5-7k mi
Replaced t-stat, coolant outlet housing, coolant resevoir.
"Mods":
MPFab intake
Bypass the bypass
Ported IM w/ aftermarket external check valve mod.
These have all been in place and fine since I bought the car @ 100k mi
Curious what you guys think. Love the little car. Going to park it now until I can get this figured out. Hopefully you can give me some guidance short of swapping out the whole powertrain or blindly replacing parts....
