Cadillac CTS-V - Ported Tb Tuning

Just installed a ported LS6 TB, I'm using efi live to tune. Does anyone know which tables need to be adjusted. I'm still figuring the mapping on this car, I'm just looking to calm the Idle down. Right now I'ts bouncing up to 3000 rpm while rolling in neutral. Thanks for the help folks.

i don't think that's a tune issue, sounds like the TB isn't sealing correctly, either the butterfly valve itself, or the gasket is leaking, or the pcv line going to the valley cover is split somewhere.

Those where my initial concerns, I've checked all the vacuum lines, brand new tb seal as well as new valve cover & valley cover vent lines. Brake booster vacuum line is intact and solid as well. I've been scratching my head on this one, because I can't find anything in the mapping that suggests this sort of behavior either....

I know porting is beneficial but I also know it's critical that u dont get too close to the plate or it won't seal correctly and will cause tuning issues. Who did the port work?

i bet it's not sealing inside the throttle body.

u want to email ur tune i can take a look at its for u vansonnnie@aol.com

i had the same problem when switching to a 90mm TB.. i had to drill a 1/8 hole in the blade and all my problems went away. its worth a shot.

i had the same problem when switching to a 90mm TB.. i had to drill a 1/8 hole in the blade and all my problems went away. its worth a shot.

i thought about that as well, but that's just gonna let more air in, IMO.

You really shouldn't have to touch anything other than the idle desired air flow to get it close. If it is swinging that wildly probably something else wrong like everyone said.

Does it nearly die and then surge or does it just hang that high?

Well now, there is oil coming out the manifold into the tb...fml. $50 says the machine shop f":":{: up a valve seal when they where going through my heads..... I'm not going to wonder why this didn't happen with the oem TB so I will be tearing this sob apart again. as heavy metals says "mod hell" haha.

Edit: it seems the oil is keeping the tb from sealing, Tb seals just fine.

i had the same problem when switching to a 90mm TB.. i had to drill a 1/8 hole in the blade and all my problems went away. its worth a shot.

Your supposed to change the scalar in the ECM.
Doing this hack way only solves idle, but all your air measurements will be off going through the rpm range.

Porting throttles has a definitive portion, used for controlling idle, if you port that portion... you have gone too far.

People have done the hole trick for years.. It's only for idle and does not effect anything else as far as the drivability or wot tuning.. It worked for me so I'm happy

I'm going to go ahead and just kick my own ass for this. I managed to swap the valve cover vent and the valley cover vent trying to beat the rain........as I walk away in shame for my stupidity.

People have done the hole trick for years.. It's only for idle and does not effect anything else as far as the drivability or wot tuning.. It worked for me so I'm happy

Just like the punch the MAF screen trick for years?.. until more people started to learn the tuning portion and noticed it hindered. Its because they didnt understand.
You are wrong thinking its just for idle - I can now assume you have never tuned a car.

Of course it works but for the wrong reason, its not ideal or good practice, perhaps you clearly didn't understand what I was saying.

Your ENTIRE table of calculations for fueling is based on the computer knowing the AREA VOLUME of the throttle which is a value the ECM looks at. You clearly did not tell the computer, hey, I have a larger 90mm throttle from a 78. Meaning, you have thrown away a good portion of the entire purpose you were trying to achieve by changing the throttle in the first place. Larger throttle, to just skew the tuning.

Your computer still calculates air velocity based on the area if your throttle was 78mm. Means, at ALL RPM and ALL THROTTLE %... your computer is fueling based on 78mm throttle, but you have added more air, without more fuel. because the ECM doesn't know what you did. This does not work. If your AFR was ideal and giving you peak before, you definitely gained zero for your mod, and was a waste of your time.

Its one of those things, your fueling could be off by as much as Ive seen 8% through all rpms and throttle positions logging, especially WOT. Easily avoidable.
Ive experienced both methods, I will never drill.

im no tuner..never said i was..i just know how to make shit work. thanks though