NS_C63

Hi guys

I need some help / advice with a few problems I am currently experiencing.

Firstly my car is 08 with PP and has the following mods.
Header, exhaust (decat), Evosport pulley, Software & Carbonio airboxes

Had new software loaded on the car 2 months ago and was very impressed.

In the last 2 weeks my airflow (MAF) has gone down from a peak of 310/315 to 285g/s. This has resulted in a drop of about 30 wkw on the dyno.

When we plugged the car into X-Entry diagnostics and measured airflow we saw that the right hand sensor was reading 1kg less air per minute at idle. Left bank 7.9 and right bank 6.9.

We assumed that on of the resonators on the exhaust was blocked and thus had the exhaust redone with a 3" pipe from headers to back box with x in the middle.

This did no solve the problem, car is still flowing less air.

I also have a problem with the secondary right hand side lambda. Keeps on throwing a error. This problem has been there for a couple of months. Not sure if the airflow is causing the error.

What are the possible problems that could be causing my drop in airflow?

Any advice / help would be appreciated.

Thanks

C63 Guy

(Bolding and comments in parenthesis are mine)

Uhmmmm... Did you try simply cleaning the filters or replacing the 02 sensor first?

Might have been a slightly less expensive and time consuming route than a new exhaust... Just saying.

Also, the car will always throw a CEL without cats unless you deactivate the rear 02s in the software.

Hope that helps.

Josh

NS_C63

Airfilters were cleaned and new sensors installed before we redid the xhaust.

pflaummark63

Did you already replace the MA sensor on the air intake--bad side?

LZH

Did you get rid of the primary cats ??? If so, that's your problem as Josh said.

NS_C63

Swopped left and right sensor, same problem.

NS_C63

Been running without cats for about 40000 km, problem only started rececently.