Hey guys, I put on my ported ls6 throttle body on yesterday morning but am wondering if this is normal..... I instantly noticed when starting the car with it there was more air flow. The idle seemed a tad bit louder as well.. I have not had the car re-tuned with it yet but Just want to make sure nothing is wrong. What would I or should I be looking for if lets say it was ported too much? I don't know if It's just in my head or what but I want to make sure the car is running right. Any advise would help. Thanks

 

Why do you think your car is flowing more air at idle now? Did you also add more cubic inches along with porting the throttle body? The engine will only "pump" the air it needs for the cylinder volume. Porting a throttle body will reduce the restriction into the engine, but will make absolutely zero change at idle since the throttle plate is nearly all the way closed at idle. The only time a ported throttle body will help the engine is as wide open throttle, and you probably will only benefit after a lot of additional engine modifications.

 

Thanks, it must be all in my head. Are you suppost to use anything on the throttle plate for lube? I get the feeling it is not closing when in park, or so it sounds that way?

 

Codes?

 

none, no problems in that department. I have headers/ cai/ full catback Borla stingers. Is it possible the plate might not be closing all the way?

 

When my TB was ported my idle went up as well until it was tuned, I was told it was because the airflow direction was changed (stock there is a bump that directs airflow differently) after tuning it goes away.

 

unless of course it was ported too far, if you hold the TB closed it should seal, if not then it is messed up and will cause more permenant idle problems..

 

With headers, CAI, and a ported throttle body it is indeed time for a custom tune. The throttle position at idle should be around 4% open. If your idle rpm has changed since porting the throttle body it sounds like the porter got into the surface right around where the throttle plate closes. Like Speed mentions - this area should not be ported, and if it has been it can cause a lot of tuning difficulties.

 

what Idle rpm should I be looking to be at? and when the car is just in park also?

 

When the engine is OFF, the throttle blade should be able to be manually pushed fully OPEN.. When you release it , it will NOT fully shut and just FLOP to a close to shut position. You should however be able to press it fully shut and it should completely seal without any gaps around the entire Throttle Blade.

Is there a HOLE drilled in the throttle blade????? There SHOULD NOT BE!

When you turn on the ignition, the throttle blade should errect to the last known good idle position. If you changed TB's,,, you most likely just need to do an IDLE RELEARN PROCEDURE. Once you do that, it should idle normally.


Idle relearn is a procedure that allows the PCM to recalibrate air/fuel ratios. This procedure may be requried after changing an air intake, MAF, porting a throttle body etc.
It should norrmally not be required if no changes have been made One exception.. . ( there may be others) If you have recently changed from an alcohol free to an alcohol containing gasoline, you will have leaned out your air/fule mixture.

Idle Learn Procedure

Automatic Transmission
Perform the following procedure in order to return the learned idle to the correct position:

1] Turn OFF the ignition.
2] Restore the PCM battery feed (if disconnected).
3] Turn OFF the A/C controls.
4] Set the parking brake, and block the drive wheels.
5] Start the engine.
6] Ensure that the engine coolant temperature is more than 80°C (176°F).
7] Shift the transmission into Drive.
8] Allow the engine to idle for 5 minutes.
9] Shift the transmission into Park.
10] Allow the engine to idle for 5 minutes.
11] Turn OFF the engine for 30 seconds.

Manual Transmission
Perform the following procedure in order to return the learned idle to the correct position:

1] Turn OFF the ignition.
2] Restore the PCM battery feed.
3] Turn OFF the A/C controls.
4] Set the parking brake, and block the drive wheels.
5] Place the transmission in Neutral.
6] Start the engine.
7] Ensure that the engine coolant temperature is more than 80°C (176°F).
8] Allow the engine to idle for 5 minutes.
9] Turn OFF the engine for 30 seconds.

The A/C compressor kicking in and out at idle speeds puts a high load on the engine at those rpms and will affect idle speeds on most Vettes... Some with modified cams have a very rough idle and may stall with the A/C on at idle...

To complete the PCM relearn...

Restart the engine and check for DIC error codes (there should be none).
10 Drive car for a minimum of 30 miles at varying rpm settings and speeds. PCM will now re-learn and adjust for the new air flow and temperature at the intake.
a) If error codes persist, repeat steps 1-7. Make sure fuses are properly inserted before repeating steps.
b) Do not deviate from the sequence outlined above. If you do, restart the sequence from scratch.
c) Steps 1-4 are also necessary if you ever disconnect your battery or lose power for any reason.



BC

 

There is a hole drilled in the throttle blade

What the hell should I do. I bought it from a guy on here

 

The throttle plate can be replaced; you could try to fill the hole with epoxy; or a tuner could try to compensate in the tune (lower the required airflow table). Best choice is to replace the throttle plate. There is zero reason to drill a throttle plate on a drive-by-wire vehicle.

Good call by the way Bill...

 

Thanks Bill, I will try that, I will keep everyone posted on this. Where Can I buy a replacement blade from?

 

I would NOT epoxy it as it will sooner or later come loose. Ive seen people weld fill it. Its aluminum and if not done properly. it will warp it.

If you decide to epoxy fill it, do a good job and make sure that it will not fall out.

Find a defective TB and change plates.

 

could I just put the plate that was on my ls1 on it? I have that throttle body still

 

If it measures the same as your plate.

The LS1 plate is SUPPOSE to be 75mm and the LS6 is SUPPOSE to be 78mm

Test the size of the plate with a caliper and see. I would send the bastard back or have him send you a non molested plate...

BC

 

Update: the car is idle at a little below 1000 rpm. It seems to surge when shifting from park to drive and so forth?

 

I'm not a bastard thank you very much. I bought this on here a couple months ago. Then i bought a fast setup that i found so i never used the throttle body. I didnt try to screw the OP at all showed pics of the throttle body before he bought it. I am hoping he can get it to work as i don't want him to have any issues. I had no idea this would be an issue as i have seen ones with holes before.

 

If you re-read Bill's post, he didn't call anybody a derogatory name. He was referring to the throttle body with the modified throttle plate.

from an online dictionary:

2. something that is spurious, irregular, inferior, or of questionable origin

 

as soon as I get home I am going to try the idle learn procedure. I will keep everyone posted. Thank you again for all the great advice.