Graphic throttle body info
The engine runs perfectly most of the time however it does run erratically after a long run at extremely light throttle and then trying to re-accelerate. When this occurs the engine runs extremely Lean to the point it will backfire buck and pop. At times when pulling up to a red light at idle it will do the same thing.
At first I thought this was a result of the 550 injectors causing a rich overall mixture and the computer compensating for it. So i reinstalled the stock injectors and has Jerry from eurocharged send me a new tune. It displayed the exact same drivability issues.
I then contacted other industry pros to help out. One led me down the path of the throttle body and gave me a good argument. Since NO 112-113 engine ever came with an 82mm TB, the calibration just isn't there. I think this is very well the case.
I took apart a stock TB and an 82 to measure a few things. Here is what i found!
The gear set and stepper motors are identical in every way. The sweepers are slightly different in the resistance value. I am going to try a set of resistors to get an identical setup to stock to see if that is the problem. Ill let u guys know.




Last edited by DonnieD; Jun 3, 2013 at 09:18 PM.




Anyhow, looking at the pics the boards look identical, at least from this side. I wonder if swapping them like Shardul said would cure the problem. Did you compare your readings to the one installed in your car, to make sure both 82's read the same?
Another thought, was the car ever dyno tuned? Or just a canned tune? My canned tune was lean and once on the dyno it was richened up and the car ran much better. Since not everyone has this issue with the 82, I'm wondering if a slightly richer tune would compensate for your problem. Maybe Jerry can richen you up a bit from where it's at now to test. Is your fuel filter, and pumps, and pump connections all in good condition?
Last edited by E55Greasemonkey; Jun 3, 2013 at 09:50 PM.
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If OP can fix this, I will force someone to give him a beej, like this.
I still get the code but just learned to live with it, I now set an alarm on my data logger so if STFT% exceeds 15% on light throttle position it flags up and I can reset when safe.
Its not a leak issue the fact that it can be replicated the same as others, light throttle slightly increased load i.e. uphill typically around 80mph and then engine stutters and B28 Pressure Sensor Signal Implausible.
I had wondered if it was year related and that certain ECU's produced on earlier models had slightly tighter parameters but that does not seem to be the case. I have seen 03, 04 and 05 models post the same issue.
I may well pull the end cap of my original 74mm and stick it on one of the 82mm sitting in the garage.
https://mbworld.org/forums/w211-amg/...-problems.html
I will keep you guys updated.
I had wondered if it was year related and that certain ECU's produced on earlier models had slightly tighter parameters but that does not seem to be the case. I have seen 03, 04 and 05 models post the same issue.
Bstudey I hope that adding fuel helps you out. Certainly keep everyone posted.
Last edited by black06c230; Jun 5, 2013 at 08:16 PM.

. Just took the car out to find some hills and bamm!! Actually was only doing about 65 going up the hill and felt the slight hiccup stft's maxed. I knew it was too good to be true. Question for others that are having this exact issue, do you guys also get a hiccup once and a while at lower speeds upon light throttle application. I do notice it sometimes around town at about 30 when I press lightly on the gas. No, it is not the s/c engaging and it feels almost identical to the one on the highway but it doesn't cause the stfts to go out of whack or throw the code. Just thinking out loud. Anybody swap the cap from a 74 to theirs yet? I may try this, seems like it shouldn't be too difficult





