Pgpatel2

Hello, i recently did a secondary cat deletes and resonator was removed; it seems like my car lost quite a bit of power or it doesnt run like a beast like it used to, it seems like my c230k is faster or accelerates faster; should i put my catalytic convertor back on, or should i get a magnaflow convertor, or a flowmaster on. Please let me know; what i should do- i want my car to be fast again :/

austinholloman

Not sure what you could have done to cause that. Unless your car is throwing codes (engine light is on) and it's gone into limp mode. For it to feel anything like a c230k, it would have to be running on half power for some reason.

Pgpatel2

Hey Austin, no codes , no errors nothing! Only thing I feel is a huge jerk when I shift from the 1st to 2nd gear , and it feels like the car doesn't pull like before, seems like it's a delay or not amusing like it used to be.

daynger

Did it do it immediately after the mods or a number of days later?

Pgpatel2

The jerks used to already happen, but you couldn't really tell too much, now it seems like the entire car shakes and I know for a fact it goes much slower than before? No idea why - members please help. Feels like back pressured after the mods idk

Lenin

Not sure if you have a C32 or a C55 but neither one should give you a problem following removal of secondary cats and the resonator. Check to make sure you don't have any exhaust leaks.

Pgpatel2

I've got a c55 2005 , so I'm not sure if I've got any exhaust leaks? And idk how to check them? But how do I check if I got any exhaust leaks or whatever the case is; thanks for your genuine replies apperciate it.

PJmak

Sounds like a 02 sensor failure

Pgpatel2

02 seasor failure? But I have no check engine lights or signs that come up? So could it still be that, without any fault dash signs coming up? And removing the secondary cats they had no o2 sensors in it.

Lenin

o2 sensor failure would give you a CEL for sure. Check all the welds to make sure you don't have any exhaust leaks. That is the only thing I can think of that is related to the changes that you made.

insame1

check the plug on the trans for fit and moisture. I am betting something got knocked loose.

Lenin

Yep. That is also a good possibility.

Pgpatel2

Hey insame, I've read some threads before they are saying it could possibly be a bad solenoid valve, or the throttle control? Or some bad maf sensors? What do you think.

austinholloman

Without it throwing codes it's going to be a really hard call on almost all those you've listed. MAF might be causing it, I remember w210 E55's having that issue a lot and the symptoms are very similar, minus the shifting issues.

PJmak

I dont think 02 sensors always throw codes.

I would start with disconnecting the battery for 15 minutes then take it for a good drive on the freeway.

Maybe the ecu needs to reset it self to get used to a different kind of exhaust

austinholloman

1. Turn the ignition key to the on (not start) position.

2. Press the gas pedal to the floor and hold for five seconds.

3. Turn the key to the "off" position (don't remove the key), then release the gas pedal.

4. Wait at least two minutes for ECU to reset.

Pgpatel2

Hey austin; I did like 2 weeks ago, so it kind of worked for couple of days, just resetted the throttle doing those steps and it felt good, now its back to what it was, I wonder if I should sell my car or if anyone has any other steps. Cheers

mrmotoguzzi00

I don't think selling it is the answer

Be patient, lots of good tech folks on here.... but it will certainly take longer with no codes for hints at what your issue is....

So after the exhaust changes you reset the ecu and it worked for a few days ?

Pgpatel2

Thanks for the positive vibes, I just want my c55 running like a beast like it used to lol; this is upsetting me :/ - basically I reset it by turning the ignition and pushing the gas all the way down for like 15-30 secs and it resetted. And it ran good for couple of days and now it feels a bit sluggish

PJmak

Disconnecting the battery for 15 minutes is the safest way of resetting the ecu then you gotta drive it a bit aggressively for it to get used to faster shifting

Pgpatel2

Alright I'll definitely reset the battery and see if that works okay, and you think I'll need my radio code? After resetting my battery because I know for some mercedes I've had in the past I needed it.

thanks

PJmak

Most likely. Make sure you have it

insame1

Get it on a star reader and post the results.

duke749

i did the same mods to my C55 and had no problems just sounds better