multiple codes which include, P0324, P0326, P0327, P0328, P0172, P0501, P0A4A, P0C47, P07E8?

2014 BUICK ENCORE
224,000 MILES • 1.4L • TURBO • AUTOMATIC • ELECTRIC
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BJOHN13
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I recently did a engine swap on my buick encore. before putting the motor in i did a code reading on it to ensure the motor was in good condition which it was. after the install my buick started and ran but its running rough. idle is rough, belt is squealing, and there is some hesistation when accelerating along with a strong smell of gas. I hooked up the code reader to find multiple codes which include, P0324, P0326, P0327, P0328, P0172, P0501, P0A4A, P0C47, P07E8. i started with replacing the knock sensor and deleted the codes and reran the code reader with similar but different results. now the codes include P0324, P0326, P0328, P07E8, P0A4A, and P0A47. I did some research into them, with the knock sensor being replaced im thinking its a connection issue rather then the sensor itself. the other codes kind of give me the thought of poor communication or connections as well. It seems the ECM, PCM, and possibly the TCM may not be signaling god or one is faulty. Im looking for input and second thoughts. I also dont want to go buy parts without finding the most likely issue but not sure how or where to start. I also must add the battery light is on but battery tested good and the alternator is showing a charge at 13-14 volts.
May 6, 2026 at 7:02 PM
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STRAILER
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Yep, the first thing I would check is the main engine wiring harness grounds to the engine, it sounds like one of them is off. If the grounds are all good, clear the codes and then turn the key on and without cranking the engine over run the codes again these will be the main hard codes we start with. Here are the ground locations so you can check them out. Check out the images (below). Let us know how it goes
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May 7, 2026 at 4:30 PM
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BJOHN13
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so i noticed the knock sensor and alternator wiring was backwards. That was fixed and it ran better but still a little rough on start up going into idle. and has the smell of gas still. i cleared the codes yet again and redid the scan, which yet again came up with knock sensor codes P0324, P0326, and P0328. along with P0172 (system too rich bank 1) and odd enough i had a new code that showed but then disappeared when i cycled through the codes again to write them down. it was C342D manufacturer control. It has not returned on the list. is it possible because the wiring was mixed up with the alternator that the knock sensor was compromised? I have yet to check that engine wire.
May 7, 2026 at 9:52 PM
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STRAILER
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The knock sensor and alternator should be okay, doe the alternator charge when the engine is running? Also, can you upload a short video of the engine idling so I can see it? The codes and the way the engine is running can still be a bad ground let me know after you check the wiring.
May 9, 2026 at 4:18 PM
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BJOHN13
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i can take a video. i ended up getting a code for the coolant temp sensor so i replaced that and now the only code showing is the P0172. I had the battery disconnected for about an hour yesterday so the knock sensor codes are now gone and have not returned, they showed as a permanent code on another code reader. So i gave that a try. the battery and alternator are working good now and charging normally. im going to try replacing the valve covers this afternoon and check for any leaks of any sort and see if the MAF is dirty or faulty. it seemed a bit wiggly when i moved it yesterday. i will take that video when i go out to work on it soon.
May 9, 2026 at 6:33 PM