drothgeb

Hey guys, need some tips.Just got the car back together after an overhaul and I'm having some issues. I removed the SC to bore the snout and fix a methanol connection. After re-assembling upon first start up of the car it idles at ~1900 RPMs. Then started fluctiating a little bit between 1500-2000. When i tapped the throttle it seemed to dip a little then rev up to about 3k(after throttle was let off). I started the car about 3 times, each time it idled almost at 2k and occasionally fluctiated.

The stuff I did when apart:

• I bored the snout and sent the throttle body to be ported, HOWEVER it could not be ported. Turns out the MOLDED ACTUATOR COVER throttle bodies can not be ported. Surprise.
• I replaced every gasket and used ultra black on intercooler->SC..
• I replaced injector O-rings.
• I replaced the surge tank couplers. Felt like there may have been a leak, there was carbon build up on Y-Pipe by couplers.
• Soaked intercooler with acetone to de-grease. Got acetone on MAP sensor. I didn't sweat it I feel that it's generally safe for sensors. I did verify vacuum indicated what seemed to be normal while the car was idling funky. Could there be leftover acetone that didn't evaporate in intercooler passages causing the funky idle? Tomorrow I will just try letting it run for a while see if it will clear up maybe.

I double checked PCV lines from valve covers to TB
Double checked metal line into back driver side of SC snout
Double checked plug into SC snout
Double checked the secondary injection vacuume lines. Disconnected the stupid one that runs between SC and intercooler and jumper around with an external lilne to make sure it wasn't broken under there.
Double checked PCV line to driver side intake tube
Double checked throttle body/Bypass valve connections werent swapped.

I did not perform the fabled "throttle body reset" I feel like boring the snout out some and then putting oem TB back on would def not cause this nonsense but I can try tomorrow if any one thinks it could make a difference.

Any one have any other ideas other thank just take everything back apart and try again. Pretty much what my next step will be if I can't come up with anything else. I'll let it idle high for a bit tomorrow and see what codes it's throwing.

C32owner

Has it not thrown any codes now already?
Only other thing that I can possibly see is boring the snout bigger with the stock throttle body, might induce an issue, not sure?

drothgeb

High idle code :-P

StarvingArtist

Really sounds like an air leak. How long did you let the silicone dry on the SC to IC joint? Maybe the car go "woke up" by opening the door, or key proximity or a button got pushed while it was in your pocket after the TB was unplugged. Wouldn't hurt to do a TB reset.

StarvingArtist

All the injectors down tight?

SICAMG

Boring snout would not cause your problem per say but the stock throttle body to gasket to larger bore could be a issue/vacuum leak.
First thing I do at the shop....spray some carburator cleaner around your connections.Idle will pick up really fast if there is a leak and you will find it quickly. Very easy and fast test.

JohnLane

drothgeb

Any one know how to test a throttle body? Found these symptoms today:

Had throttle body off. Played with blade a bit noticed it seems a little bit cracked open. Pushed it closed a bit and it seemed to go back to the same position but defentely room to go more closed. Put TH on, started car and it idled perfect cold start idle then slowed down after a sec to regular idle. I tapped the gas and rps whent up to about 3k and held after letting off gas. I shut the car off.

I pulled the intake and gently pushed the TB blade slightly closed. Started the car and idle was LOW. 800 rpms steady. I pushed the gas and it BOGS. Would not rev.

Pulled intake and pushed TB blade open letting it spring return closed. Started the car and idle was high, 1800RPMs. Pressed the gas and it spike to >3K and stayed after off throttle.


Any one know how to test a throttle body or the wiring to the throttle body?

JohnLane

Notdke9fdkfjekrjrkj123

If you have access to a star system i would try to do a throttle reset,i had the same problem when i installed a 82mm tb,had to be reset with star.
as you are installing the same tb it shouldnt be necessary but who knows? after all its a Mercedes

drothgeb

Really!?!? No I don't have star. Man that's a bummer to hear. I'm going to smoke test today just to be sure, but I feel like being able to mess with the TB flap and have different symptoms is a pretty good indicator of trouble. I did the stupid, potentially made up, TB reset unplugging it and what not to no avail.

I have a used TB showing up thursday. If it smokes good, and the different TB doesn't do it I guess I'll try to chase down some one with STAR or maybe buy my own set up finally.

new55

i am guessing you don't have the throttle body connector and the bypass valve connector reversed ? or
manual TB reset
1. Put tb on and reset the ecu with a scan tool.Dont start the car yet!
2. Go over to the throttle body and unhook the cable going to it.
3. Turn ignition key to the stage right before the car turns on. (position 2)You should get a error on the dash. (ESP Visit Workshop) wait 20 seconds and then turn the key to the first position not 0. leaving key intact.
4. Plug the cable back in.
5. Now go put the key to the stage right before the car starts and wait 3 min,the car will re adapt the throttle body and you will hear it move on its on. While this is going on, put everything back together!
6. Start car from position 2, and everything should be okay, tap gas peddle, rpm should drop normally, if they get stuck, or if you have a CEL, you did NOT do the reset correctly!

sorry if you already tried these

drothgeb

I do not have them mixed, I keep those suckers marked.

Anyways, I did a version of that procedure. That one has a couple extra steps like resetting codes via scan tool first and the 3 minute wait.

I guess it cant hurt to try again with the slightly varied potentially made up procedure haha

C32owner

Hmmm if you been playing with the blade angle of the throttle body then I think yes you need to do a reset via Star. I say this as when I had my C32 AMG I did not even disconnect my throttle body, however I went in to clean it up and in doing so I moved the blade manually open and closed to give it a good cleaning and when I went to start the car after I had issues. Had to get the car in to merc for them to reset it. Might be something worth trying to reset via star if you can get hold of someone in your vicinity.

C32owner

Did you come right and find the issue mate?

drothgeb

It's embarrassing to say haha. Yuuuuuuge airleak. When putting the intercooler back on the front side of the bypass valve gasket pushout out of it's seat into the SC and I didn't notice. Looked fine from the visible portion on the backside of the SC/intercooler but if you looked into the SC snout you could see the side towards the middle of the SC pushed through into the SC. Anyways, pulled it again, replaced gaskets again, and all set.

C32owner

Ah awesome, glad you found it, always a relief when you get an answer!