Need help figuring out why engine makes weird noise 2.2T AAN when warm
05-21-2024, 12:03 PM
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Need help figuring out why engine makes weird noise 2.2T AAN when warm
Hello everyone,
I'm reaching out for support regarding a persistent engine noise I've been battling for approximately two years. The engine in question has been completely rebuilt from the ground up. In the process, we even swapped out the engine block.
You can hear the concerning sound by viewing https://we.tl/t-20tyPkETQV . Below are some important details:
Head:
Additional Efforts:
Despite the extensive work, the problem persists. The issue of "piston slap" seems unlikely as that typically happens when the engine is cold and disappears upon warming – the reverse of my situation. Yet, considering everything else has been replaced or inspected except the pistons, this still is in the back of my head. Also, I was thinking of bronze bushings inside FCP rods? but I believe the sound should be also with cold engine then
An interesting observation is that substituting to different OEM injectors lessened the noise by about 10%. Could this point toward an wiring issue? We used a stethoscope, and the sound seemed most pronounced around injectors 3 and 4 but this could also be an echo from the block...
It’s worth mentioning that oil pressure readings are ideal, and the vehicle has no loss of power—it drives just as a stock AAN should.
If there are any additional questions or information needed to diagnose this issue, please feel free to ask. Thank you for your time and assistance!
I'm reaching out for support regarding a persistent engine noise I've been battling for approximately two years. The engine in question has been completely rebuilt from the ground up. In the process, we even swapped out the engine block.
You can hear the concerning sound by viewing https://we.tl/t-20tyPkETQV . Below are some important details:
- Noise Characteristics: The odd noise only appears once the engine reaches operating temperature; there are no unusual sounds when it's cold.
Head:
- Serviced in its entirety.
- Replacement of springs, cam chain, different camshafts (7a cams).
- Valve servicing.
- Cleaning of oil channels.
- Overall, every component within the head has been addressed.
- CNC operations
- ARP headstuds
- Changed to a different AAN block.
- New crankshaft installed.
- Upgraded with ACL bearings.
- FCP rods.
- All block components replaced except for the pistons, which were thoroughly measured and inspected, appearing to be in great condition.
Additional Efforts:
- Experimented with various high-grade engine oils and additives from Liqui molly.
- Swapped coils ( TFSI ) and injectors ( different set of OEM ).
- Tried another ECU ( tried MaxxEcu and other Motronics )
Despite the extensive work, the problem persists. The issue of "piston slap" seems unlikely as that typically happens when the engine is cold and disappears upon warming – the reverse of my situation. Yet, considering everything else has been replaced or inspected except the pistons, this still is in the back of my head. Also, I was thinking of bronze bushings inside FCP rods? but I believe the sound should be also with cold engine then
An interesting observation is that substituting to different OEM injectors lessened the noise by about 10%. Could this point toward an wiring issue? We used a stethoscope, and the sound seemed most pronounced around injectors 3 and 4 but this could also be an echo from the block...
It’s worth mentioning that oil pressure readings are ideal, and the vehicle has no loss of power—it drives just as a stock AAN should.
If there are any additional questions or information needed to diagnose this issue, please feel free to ask. Thank you for your time and assistance!
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