Seeking assistance as I've exhausted my very limited car knowledge now... Can someone throw me some ideas on what would be causing my fuel trims to look like this? I have no engine mods other than a cat back exhaust. Cars sat at IAM 11 but to be honest not sure if this is from a fairly reset ECU reset, car seems to put IAM at 8 on reset. But then again I also do look to have potentially had some knock at 2500-4099 rpm @ 2.00-3.99 load. A bit lost with it all now so any help appreciated!

 

Looking at your fuel trims you have an air leak, check the turbo inlet for rips/tears or broken hoses, ideally get a smoke or pressure trst done to try and help pinpoint it.

 

i did think this but I do have a smoke tester so I've ran that a few times now but I can't identify any leaks. Looking at the trims is there anything else it could be or are we pretty certain it's an air leak?

 

Could be a bad maf or o2 sensor, but I'd still say its a leak assuming it was running fine before. Could also be mapped for an intake you don't have?


Smoke testers also don't always generate enough pressure to confirm a leak, see if anywhere nearby can offer a pressure based test to see what's up.

 

Yes smokers testers run at <2psi typically.

Pressure test it @ 5psi and see if it holds that (1psi loss per second is acceptable). If it holds 5psi, try it at 10psi. Listen for leaks and squirt soapy water at any suspect areas.