[blackgoat90]

TL;DR Version: After changing throttle body back to stock, ECU isn't managing throttle correctly, is there anyway to reset it (LS2, DBW)? It's actively choking itself out when slowing down. It could adapt going to the larger TB (still throws a code but runs okay) but now its not adapting back.

More details: I was messing with a 103mm LS3 Throttle body, and that was actually going okay but eventually it throws a P1516 code, sounds like its confused by the amount of air. Makes sense, went back to stock to get through smog because I can get it tuned with the new TB later, and now it dies most of the time I coast to a stop, or it struggles and drops to a couple hundred RPM before leveling out. This isn't helping my misfire codes...

I also recently put on an MSD intake manifold which is CA-legal, but I don't think that is the cause of the issue with the throttle body. The car has a cam but its been there forever and idled without issue on this tune, seems like the TB was the principal change that caused the behavior.

I looked at a scan and while I'm slowing down and off the gas I see it close itself to 12% even when RPMs are already dropping like a rock. Is there a way to reset the TB in the LS2 cars? I'm assuming that's the problem. I've pulled the battery, cleared codes, re-flashed the tune, and none of that changed anything.

 

[Nothubertjfarnsworth]

Larger DBW throttle bodies need to be tuned for. There is an area scalar value that needs to be changed so the ECM knows how much to open/close the blade for a specific change in airflow.

if you just temporarily swapped on a bigger TB without a retune, you likely just need to do the "clean throttle body" in hptuners. Resets the idle learn tables.

 

[blackgoat90]

Larger DBW throttle bodies need to be tuned for. There is an area scalar value that needs to be changed so the ECM knows how much to open/close the blade for a specific change in airflow.

if you just temporarily swapped on a bigger TB without a retune, you likely just need to do the "clean throttle body" in hptuners. Resets the idle learn tables.

I know it needs to be tuned for but it honestly ran better untuned than my stock throttle body does now.

Thank you, but is there way to do that without HPTuners? I only have an EFILive AutoCal.

 

[Sacrifice]

Im sure the manifold isnt helping the cause

 

[blackgoat90]

Im sure the manifold isnt helping the cause

In what sense? Because it's a larger manifold or because those are apparently prone to leaking?

It's odd that the manifold and large throttle body would run okay (aside from eventually throwing the ranging code) but then going back to the stock throttle body produces the issue. I can also tell that the computer adjusted the idle throttle body position from about 20% down to 16.5% with the new throttle body. Since putting the stock one on, it hasn't reset to the larger opening.