dcpwhit Posted May 2, 2020 Share Posted May 2, 2020 This is NOT a Legacy, this is a question a out my friends Impreza. I own a Legacy and have been lurking in this forum for years. You guys are fantastic and never lead me wrong. Hoping you guys are willing to help. My friend let the original ej253 die in his 2006 Impreza. He bought a JDM ej253 to replace it. Install went easy enough. At high rpm (5000+) the car throws P0302 and P0301 and goes into gimp mode. We've tried everything random thing we can think of- Changed Spark plugs/wires Changed coil pack Changed cam angle sensor Changed crankshaft sensor Changed fuel pump Changed VVT valves Cleaned MAF sensor Used 2 bottles of sea foam to clear the carbon build up. Cylinder 2 had the most. Valve cover gasket Adjusted valves Checked for vacuum leaks Replaced PCV Valve Replaced O2 sensors (pre/post cat) Compression test results- C1: 155 C2: 170 C3: 160 C4: 155 Originally had the USD wiring harness, switched to the JDM harness. Still throwing codes! And I've exhausted my idea bank. Is there something I'm missing? Sent from my Pixel 2 using Tapatalk Link to comment Share on other sites More sharing options...
Keyan Posted May 2, 2020 Share Posted May 2, 2020 shot in the dark but check the teeth on the crank sensor trigger wheel. do you have access to an oscilloscope to read the crank sensor signal live? Link to comment Share on other sites More sharing options...
dcpwhit Posted May 3, 2020 Author Share Posted May 3, 2020 I'll look into the crank sensor teeth. What am I looking for? I do have access to an oscilloscope. Will have to look into that this week. Currently going to replace his camshaft gear. It's slightly rusted. Sent from my Pixel 2 using Tapatalk Link to comment Share on other sites More sharing options...
Keyan Posted May 3, 2020 Share Posted May 3, 2020 looking for a chipped tooth or maybe its bent causing it to go out of alignment. you're probably misfiring because at high rpm the crank sensor cant read the teeth properly. either you have mishapen teeth or there's electrical noise due to something else causing poor signal to the ecu at high rpm. maybe a bad ground? you could try running a separate ground from the block to the negative terminal. these are just guesses. Link to comment Share on other sites More sharing options...
dcpwhit Posted May 3, 2020 Author Share Posted May 3, 2020 Changed left cam sprocket and crank sprocket. They were both a little rusty. Went for a drive and got a P0302. No P0301. Hurray for progress? Might try and get an oscilloscope. Unless anyone else has any ideas? Sent from my Pixel 2 using Tapatalk Link to comment Share on other sites More sharing options...
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