ALAN2000

I have a 2012 with 60K miles. Was in an accident with mainly sheet metal damage all over. Car was at repair shop over 5 months. Exhaust was dropped, oil and coolant lines all disconnected in front end, radiator was replaced along with sheet metal and paint work. When I got the car back after a few miles the CEL came on with codes saying both catalytic converters were bad (working at low efficiency.) Also noticed turbo boost was low. Long story short, insurance company replaced both cats. (Makes no sense that at 60K miles both would go out as they should last 2x that mileage, and not possible/probable to have both fail at the same time with low miles. So I figure the shop did something that screwed them up or a sensor or leak in exhaust from accident was causing CEL in error.) When I got the car back from the dealer noticed that turbo boost was still low after cats were replaced. Stock is 14.5 PSI and after tune was 18-19 PSI. After collision repairs boost only goes up to 8-9 PSI. Would not surprise me that when shop took car to the dealer to deal with CEL codes, the dealer may have reprogrammed ECU and erased the tune. But that would not explain why boost is now less than factory stock. Any suggestions what to look for? Not sure if the car should go back to a dealer or take it to independent shop that did tune to diagnose and reinstall the tune. Annoyed that after sitting weeks at the dealer waiting for the cats they didn't address low boost issue.

Robert AMG

iTrader: (1)

8-9 psi on stock 2012 is normal.

ALAN2000

Where are you getting that info? According to Road & Track, Car & Driver, Autoweek, etc., it's 14.5 PSI stock.

https://www.roadandtrack.com/car-sho...enz-cls63-amg/

https://www.caranddriver.com/news/a1...benz-cls-news/

https://www.autoweek.com/drives/a198...ve-car-review/

dustinN

I think 14.5 PSI is the max number for the brand new car in perfect condition. This number is lower for older cars.

1MavRick

did you measure the boost before the repair? what gear are you measuring the boost? you dont get the full boost until 4th or 5th gear. its limited in the lower gears to preserve the drivetrain.

1MavRick

if the car has lost over 50% of boost...then there is a serious problem. no matter how old it is...

ALAN2000

Yes, I have an OBD2 reader that connects to my iPhone via Bluetooth that I use with ODB Fusion app. Once or twice a month I'd fire them up and get readings around 18 PSI boost. I also have a Draggy and 0-60 was typically 3.8 seconds. After car repairs 0-60 has dropped to 4.2 seconds and boost only 8-9 PSI. I also did a few WOT runs away from civilization after repairs that should have maxed out boost and was still under 10 PSI. Between the body shop and insurance company it's getting really frustrating trying to get the car back to pre-accident condition.