SpeedyRu08 Posted February 1, 2021 Share Posted February 1, 2021 (edited) I got this 08 LGT 122k miles, with cross-threaded spark plug threads (previous owner was trying to fix a misfire), I retapped the threads & put in a Helicoil. Also just did a timing belt job on it while putting the head back on. I got it running again and on the first start up, this thing runs like dog sh*t. The only codes it's showing is for the front o2 sensor. It ran pretty rough before I fixed the spark plug and had misfire codes for all 4 cylinders, and when I took the timing cover off it looked like the tensioner plunger failed and may have cause the engine to jump time (timing marks were off about a tooth). There's also a massive exhaust leak coming from around/under the turbo area that I haven't been able to fully track down. Could this thing have a bad PCM and what's the best way to determine that? Or what would be the ideal tests to run and things to check first? All the plugs and coils LOOKED new. And could the exhaust leak make it run so rough? Any input is appreciated Edited February 1, 2021 by SpeedyRu08 Typo Link to comment Share on other sites More sharing options...
JJr Posted February 1, 2021 Share Posted February 1, 2021 Double check that the coil wire connectors are fully seated. Link to comment Share on other sites More sharing options...
dgoodhue Posted February 1, 2021 Share Posted February 1, 2021 I would fix all the problems before trying to diagnose a bad ECM. Exhaust leaks can definitely cause an O2 code. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted February 1, 2021 Share Posted February 1, 2021 Are you sure the timing is spot on? My preferred method is to count the number of teeth between pulleys as per FSM. Link to comment Share on other sites More sharing options...
SpeedyRu08 Posted February 2, 2021 Author Share Posted February 2, 2021 Are you sure the timing is spot on? My preferred method is to count the number of teeth between pulleys as per FSM. I'm almost certain it is. I tried reusing the old belt because it only had like 20k miles on it but the marks didn't line up at all so I got a new belt and the pulleys I needed. The left (driver side) intake cam gear was about a half a tooth off but I've seen that on several other DOHC timing belt jobs I've done (YouTube videos too). Everything else was spot on. Link to comment Share on other sites More sharing options...
SpeedyRu08 Posted February 2, 2021 Author Share Posted February 2, 2021 I would fix all the problems before trying to diagnose a bad ECM. Exhaust leaks can definitely cause an O2 code. I'm just going to replace all the gaskets on the side where the exhaust leak is and see where that leaves me. I did a smoke test by putting the smoke machine hose in the tail pipe and plugging the tailpipes and all the smoke was coming from the turbo area. Link to comment Share on other sites More sharing options...
SpeedyRu08 Posted February 2, 2021 Author Share Posted February 2, 2021 So I just found that the up pipe is in 2 pieces. The upper piece that bolts to the turbo is still attached but I was able to wiggle out the lower part that mounts to the exhaust manifold. I can't imagine this is normal. Can anyone tell me if this pipe is supposed to be welded or something and be one piece? Link to comment Share on other sites More sharing options...
xt2005bonbon Posted February 2, 2021 Share Posted February 2, 2021 There should be a flex joint there. Maybe that's probably where it is broken? Link to comment Share on other sites More sharing options...
Max Capacity Posted February 2, 2021 Share Posted February 2, 2021 It should be a solid pipe. Not two pieces. Is it OEM of aftermarket ? It should be OEM. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
xt2005bonbon Posted February 2, 2021 Share Posted February 2, 2021 The OEM has some kind of flexible area though IIRC. If you were to remove the heatshield, you'd see an accordion like pattern in the middle of the up pipe. But yeah, not as flexible as you'd think though. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted February 2, 2021 Share Posted February 2, 2021 Now I remember I was inspecting a catless wrx or sti uppipe, which I still have on the 05. Looks like that without the heatshield. http://www.fawbush.org/images/2010_1_4_sti/05sti_uppipe1.jpg Link to comment Share on other sites More sharing options...
SpeedyRu08 Posted February 3, 2021 Author Share Posted February 3, 2021 It's on OEM pipe. After looking at it closely somehow it snapped so I'm gonna replace it with another used one I have and see what all that fixes... Link to comment Share on other sites More sharing options...
xt2005bonbon Posted February 3, 2021 Share Posted February 3, 2021 If you are serious in getting this car in top notch, etc.., I would consider using a logging tool so you can see what the ECU is doing. I personally use the BtSsm app for android. The original sensor is no longer available, but there are other sensor options which can run with the app. You'll be able to check the amount of fuel correction for different driving conditions, which can help you figure out if you have vacuum leaks; report of misfire per cylinder, check if your OCVs are working properly, get alerted for knock which is important. --> https://legacygt.com/forums/showthread.php/btssm-bluetooth-adapter-app-v-1-closed-229709.html Link to comment Share on other sites More sharing options...
Max Capacity Posted February 3, 2021 Share Posted February 3, 2021 So the 07-09's have a flex joint...learn something new everyday... 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
SpeedyRu08 Posted February 8, 2021 Author Share Posted February 8, 2021 1 new uppipe and an oxygen sensor later, we have misfires on cylinders 1,3, & 4 actually showing up on the scanner. The check engine light only flashes intermittently but the car runs like shit constantly. I'll try checking the coils and injectors Link to comment Share on other sites More sharing options...
xt2005bonbon Posted February 9, 2021 Share Posted February 9, 2021 You should carefully check for vacuum leak, especially that blue T hose connection underneath the intake manifold. you can access it by removing the intercooler. Link to comment Share on other sites More sharing options...
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