Engine knock after jump starting 2012 R-spec

[triplington]

I was driving the car and it was running fine. Stopped, then 10 minutes later when I got back to the car, it wouldn't start, slow cranking and dimming dash lights. I jump started it from another car but then there was a problem. There was a bad knocking, sounding like a timing problem, but still a relatively smooth idle. I thought the ECU might have lost its settings so I carefully drive it the few miles home. The car runs smoothly, seems to (gently) accelerate as normal, it feels OK but from the sound there is something wrong. There is steady knock at idle, it goes away when accelerating up to about 3000rpm then comes back, and gets louder when coming off the power. Cruising at a steady 45mph the engine sounds normal. I suspect it's a timing chain or something in the variable valve timing system but the engine runs smooth, and there are no engine codes, and the car only has 40k miles and why after a jump start. Could the ECU be damaged?

 

[Ozy44]

I would try to figure out where the knocking is coming from. The old PVC pipe to you ear as you move it around the engine bay is a good start. Why did it need a jump start? How old is the battery? Have you had the battery tested since this issue? How many volts is alternator putting out?

 

[triplington]

I think I've found the problem. I changed the oil and there are metal specks in it, I think I've damaged the main bearings. When I checked the oil level it was about 1/4" below the min on the dip stick. The engine routinely burnt some oil as they all do, but not excessively. I got no warning, no low pressure light and I was using full synthetic oil changed about 5K miles ago. I still don't know why cranking the engine with a low battery after it had been running normally 15 minutes earlier did this much damage? I owned the car from new and the 10 year warranty ended in Dec 21, life sucks. I might take the car to the dealership just to confirm my diagnosis, repair estimate, and how much they would give me for it, 10 year old R-spec, 40k miles, good condition but bad engine?

 

[Ozy44]

Un

I think I've found the problem. I changed the oil and there are metal specks in it, I think I've damaged the main bearings. When I checked the oil level it was about 1/4" below the min on the dip stick. The engine routinely burnt some oil as they all do, but not excessively. I got no warning, no low pressure light and I was using full synthetic oil changed about 5K miles ago. I still don't know why cranking the engine with a low battery after it had been running normally 15 minutes earlier did this much damage? I owned the car from new and the 10 year warranty ended in Dec 21, life sucks. I might take the car to the dealership just to confirm my diagnosis, repair estimate, and how much they would give me for it, 10 year old R-spec, 40k miles, good condition but bad engine?

Unless you are the original owner, there's no telling how the previous owner may have punished your ride. From what I understand, some of the 2012 R specs burned a lot of oil between changes. It"s entirely possible your spec didn't get oil when it was needed. Good luck with your repairs.

 

[joegr]

Un

Unless you are the original owner, ...

...I owned the car from new...