If you decide to 'take apart the TB' past where you remove the plastic side cover and the intermediate idler gear, let me know how you got that butterfly shaft out.
I have tried everything I can think of, run google till it panted, and still don't know how to remove that shaft.
Has to be possible, otherwise, how would you be able to bore the throat ?

 

Will do Al, just not sure how far apart I will be going, when I put it in the car, it was clean as a wistle and functioning top notch, I am unaware if something has changed in the last few weeks since I installed it, or if it is something else completely and I am stuck on the TB since it was my last mod. I know it makes sense, but so would the pedal assembly, MAF sensor, throttle sensor, sprint booster, etc...

 

Did you install a new O-ring when you did the TB install?

 

I had the same problem, but it was semi-self induced. I did the Waldig shaping on the leading edge of the throttle plate and TB opening. I took the plate off to round it, and when I got it back on, I didn't seat it completely in the center, and created a vacuum leak. Car surged the same way. Once centered, it ran fine.

Bottom line: you have a vacuum leak. Try the propane.
Mike

 

Sure did

I tried a little something last night to see if I could get any code. I barely loosened the maf sensor just enough that a tiny amount of air could pass and let it run for a little while, finally a code. It obviously pulled a MAF sensor issue, but also uncovered that my IAT sensor is not functioning, why that did not trip a CEL I do not know, or maybe my actions caused it to finally fail 100%, either way, I think I am going to try the IAT sensor, then the torch if it is still present.

I believe a faulty IAT sensor would cause these issues I am having, anyone care to confirm?

Edit: Upon further investigation, can anyone confirm that the IAT sensor in the NA car is part of the MAF sensor? I can't find a part number anywhere and see things eluding to the fact that it may be part of the MAF...

 

Yes, MAF & IAT are both in the same assembly.

 

Thanks, that is what I had concluded, but needed the confirmation.

I think I am going to try the MAF from the V8 that I have sitting at home. Can't be any worse than what I'm getting now...

 

No improvement with the V8 MAF. Going back to the 68mm this weekend, as I do not have enough time to properly troubleshoot while I am trying to get everything else ready for the Dragon. Hopefully that will fix the problem for me, at least for now...

 

When I was having these exact same issues what fixed everything in the end was a little high temp rtv and making sure everything on the needswings cai was snugged up. I took the tb off, lightly coated the seal with a little rtv, let it tacky up a bit, replaced and made sure it was all centered up, used my micro torque wrench to snug it up, re installed cai and not an issue since.

 

I also installed the needswings catch can at time I had the CAI off but doubt that had anything to do with the vacuum leak.

 

I also used some RTV, didn't make a difference. I am going to try the propane method this weekend and if that comes up with nothing I am going to switch back to the 68mm.

 

did you use a torque wrench to make sure you had it snugged up tightly?

 

Problem sounds like the TB "O" ring not centered or just crushed. Could also be the elbow not mounted preperly and leaking.

 

I used a torque wrench. I am convinced it is either the elbow or the MAF body that is leaking. I centered the tb, used RTV, used RTV to hold the "O" ring so it is not crushed or misaligned. I have checked all the hoses around that area at least 10 times and everything looks and feels very snug.

 

What a pain!

 

Mine was leaking where the elbow mates to the TB. The gasket that goes on the inside of the inside of the elbow was messed up. I smoothed it out and put just film of lube around the parimeter. The other thing I had a problem with was the large MAF snsor. I removed the sensor it came with and put the sensor from the old MAF in place. Works very good now. Let me know if anything helps.

 

Let me know by Thursday next week if i need to bring a 74mm TB, 68mm TB, 68 mm MAF sensor, and the elbow to the dragon.

 

Gentlemen, first off, thanks for all that offered suggestions. Me and a buddy, who is also a FANTASTIC mechanic, spent over 5 hours in his shop trying to figure this damn thing out.

• We swapped to the OEM MAF (OEM sensor as well) - nothing
• Checked the new O-ring we installed, reseated it - nothing
• We swapped to the V8 MAF sensor - nothing
• Carb cleaner around the TB - nothing
• Propane trick - nothing
• Used a smoke machine to test for leaks - nothing
• Used a Verus (snap-on) diagnostic computer and made the ECU essentially relearn the idle throttle positioning - nothing
• swapped to 74mm TB and V8 MAF - nothing

Since none of our tests found any leaks, we figured all was snug and tight, but just for ***** and giggles, we decided to RTV the TB. Sure enough, it is now running perfectly.

It was a vaccuum leak that was not evident under normal running conditions, only under extreme acceleration. I drove around with the snap-on diagnostic machine in the car and it did not even find the issue.

Long story short, even though there is a factory O-ring and it appears to be sealed, it probably is not, try an even bead of RTV, as others have suggested, because there is apparently no other way of testing for this, except to just seal it.

Wish I would have done it from the start, but silly me, I figured OEM mercedes parts would fit together well enough to not cause leaks, and if there were leaks, I would have thought our normal diagnostic procedures would have found it like in all other cars I have worked on.

Either way, just glad it is done and running perfectly before the Dragon

 

Glad you found the fix. You were certainly methodical in your pursuit. Wonder if this may be my cold air issue too, where when the car is cold start below 40 degrees it just stalls and no pedal response, and this was after the 74 mm TB, with the 68 before it was just fine. I don't think it is because above 40 it's fine.

 

Well, it came back...

As I was entering the Fontana Lodge at the Dragon

It drove fine for a week and the 400+ mile trip to the Dragon, then started acting up again. Since I knew ALL my driving was going to be above 2K RPMs, I said screw it and drove the car like I intended to. Found out a few things in this endeavor.

The problem is sporatic. May start after going for miles, may start with the car being started, but stop shortly thereafter.

If it is idling high, I can keep the car in gear till I am nearly stopped, bringing the RPMs down below 1,000, it will not rev itself or idle high

I am at my wits end with this thing. If anyone has any ideas, please let me know. I am about to drop it off at a shop and tell them not to call me until it is fixed, but I don't trust them and don't think they are going to do anything different than what I did, except start replacing (expensive) parts with my cash