Haven't been here in a while and was hoping to find that a solution has been found for the annoying bucking/hesitation caused by the 82mm TB at throttle tip in. Has a tuning solution been developed? I don't drive the car much anymore because of it.

Todd

 

Does the bucking/ hesitation happen when you reach/go over 2k RPM in say 1rst, or second gear by an chance?

 

I'll need to watch the rpms closer, but it does occur in first and second when accelerating moderately just as you depress the throttle. Numerous others were experiencing it last I checked and it was caused I believe by the ecm seeing an unexpected amount of airflow in regards to the throttle opening.

Todd

 

Is it the gt3tb? I noticed I couldnt drive the car smooth with that and very little throttle would engage the blower.

try buying a 550 82mm tb and swapping that on there,ill bet you it will drive like stock

 

It's the Eurocharged 82mm TB. Not sure which that is...

Todd

 

Did you have the 82mm GT3 TB?

Gt3 is what i had and never had a problem , Drove to Florida and back with no driveability issues at all..only problem they really cause is the tons of air they pack in there with such ease

 

check for vacuum leaks and do a throttle body reset. If you haven't done the reset since the install, that could be your culprit.

 

I was at Timmay Fest in 2010 and while on the dyno for a tune I'm pretty sure the reset was done. No vacuum leaks are present. I've also had the PCM reflashed recently and that had no effect. I was told it was expected by one of you old employees, Greg G. who is no longer there. Said that the air flow after the TB install was significantly higher than what the PCM expects at throttle tip in which causes the momentary hesitation. So this is not normal? Could it be a issue with my particular TB then? I've heard others complain about it and was just hoping for a tuning solution.

I also think you guys checked out the TPS sensor too while I was in Columbus.

Todd

 

How did they route the oil vapor hose on your tb?

 

Use a SDS and raise the idle 60rpm's and that should get the throttle body blade at the correct angle degree. It seems that it is an adaption issue and this is what I did and recommended when I or another shop/client installed my TTM 82mm TB Kit when I was using the GT3 82mm TB.

 

great point bruce, I forgot about that.

 

If you have a tb that is throwing an idle to high code its because you need to tap the oil vapor line where there is ALOT of vaccume.that will lower your idle rpms.

try this,unplug that hose and watch your car idle at 3500 rpms.

I have about 3-4 people pming me with tb issues,right now.

If you have a leak before the tb it will throw the p0505 code for idle malfunction,that is because the car is trying to litterally close the blade 100% to get it to idle lower.

If you get a tps under 1.6% you are border line going to flag a 505 code.the second the ecu sees 0.9-1.2 it will pend a 505 code

 

Oil line connected at intake tube about 4"from TB.

I don't throw any codes, and I don't think the issue in my case is connected with an idle condition. It idles fine and as long as I keep the throttle at a very low opening when driving everything is good.

Here's more detail on what happens in my case. I'm cruising at say 1200 rpms, I give it some gas and at this point I get the hesitation. If I log TB position I can see the TB momentarily close and open during this situation. This momentary close is what causes the bucking sensation. It's like the car sees a parameter, air flow, or ?, that goes out of bounds vs TB position and there is no valid entry in a look-up table for what it's seeing if that makes sense. Therefore the throttle closes. Just my hypothesis.

Todd

 

I have a mercedes 80mm tb if you want to try that out

 

Sorry to bring back an old thread. But, how do you use the SDS tomraise the RPMs? I searched and looked in the STAR thread but no ino or steps on how to raise rpm with SDS. Anyone know how?

 

ME=ADAPTATIONS=CORRECTION PROGRAMMING=IDLE SPEED(IN GEAR OR N/P)

 

thx!

 

I have the exact same problem and not enjoying driving my car with the hesitation/bucking at tip-in with the S550 82mm TB. I've reset ECU adaptations, reset throttle body and raised the idle in P and D 60 RPMs in STAR to get rid of the P505 code, but the annoying cutout/herky jerky/bucking is still there at tip-in. This never happened when the car was stock, it started after the tune so I'm hoping this is a known issue that can be tuned around. I read some other threads indicating this is caused by the MAP sensor so I ordered a replacement OEM Bosch MAP sensor direct from Germany and planning to install it in a few days. Supposedly, the DC Japanese brand MAP sensor that many cars come with can also cause this tip-in bucking issue. We will see.

If you got this issue resolved, please post or PM the solution. My car runs amazing except for this one frustrating issue. Thanks.

 

Please keep us posted. Thanks

 

Same here, i'm having this EXACT issue... I ended up pulling out my ECU for the 3rd time, and sent it to Tony @ BIP (its currently still there). Long story, but in a nutshell... yesterday he was hinting to me like my ECU was damaged??? I have no idea how that would have happened or what that means, and he really didn't know yet until further testing/inspecting was done. So I'm waiting on Jason (the owner of BIP) to call me back, to update me on it.

My SL55 was and has been running fine, except for the same small/annoying issue that most others in the post are having. So I just don't see my ECU being damaged, but what do I know...

 

I doubt your ecu is damaged, are you logging AFRs when you get that stumble and there after?

 

not yet, i have all other upgrades pulleys, injectors, 82mm TB, HE, etc. then headers/wideband was going to be the next part. once i got all those mods installed, and the ECU tune from BIP, i started having this hesitation issue right away. im planning on pulling the trigger on headers/wideband soon, but just want to be sure this problem is solved before i go any further.

so no, i have not been able to log AFR. plus i have not been driving it hard since i do not have a wideband on it yet. problem "usually" starts in my neighborhood in low RPM/1st gear, but also happens at other times as well.

 

How does it ride after the issue, is everything fine?

 

pretty much this is how it normally happens. start the car, CEL is sometimes off and others its on after startup (my SDS shows map sensor code, when CEL is on), and when its on it will sometimes go away after driving it for awhile. anyways after the car is started and driving it through my neighborhood, it will normally start hesitating about an 1/8th of a mile down the street, (in 1st gear/low RPM). when this happens it usually idles like *****, i can cut the car off, and turn it back on, and then it usually idles fine.

however, if the car is idling fine, when i tap the throttle its sluggish in low RPMs still, but after about 2 or 3k RPMs, it revs fine.

 

Seems like that hiccup issue for you, it idles rough then when you cycle the key it's fine and getting map code. It will also lean out a lot in that instance
This is a tune issue