I have been having trouble with my car not wanting to start and when I put it into reverse it wants to die. It's an A4 with a mild cam Heads and FAST. I was told that if I were to drill a small "bleed hole" that would fix the problems.

Anyone here about this?

 

It was done to my car however I believe it can be tuned out.

 

Did it effect the idle or rpm any?

 

That right there is what I would call a "hack". The idea behind the bleed hole is that by allowing air to bypass the throttle body you can have enough air to let it idle. Since all C6s are Drive By Wire, they have no idle air control valve; you can simply recalibrate the idle airflow via the TB to make it idle. That is a more elegant solution

 

Yeah, it worked but I agree, its a hack.

 

MTI Houston drilled a hole in my TB in 06 or so when the cam was installed. I thought it was clever at the time.

 

I would imagine this issue could be fixed by a better tune, no?

 

Yes, it can be tuned out.

 

I would recommend getting the car tuned with those mods. If you've already had it tuned by someone, i'd take it back to get a better tune.

 

The guy that tuned it said he would drill the hole. I am pretty sure if I ask him to retune it, it would either cost me money, or he would say "it's already tuned as good as it will get"

As long as this fixes it, I'll be happy.

 

Thats a HACK TUNE if I ever seen one. The guy should fix the IDLE / TUNING issues without charging you again. I still think you should have gone and had a PRO TUNE as the issues would be fixed and you would get
the dyno numbers on the dynojet and you would have been much more
satisfied. How can you undo that now ?

 

There is a minimum air flow table in HP Tuners which I think makes drilling a hole unnecessary.

 

Yes there is

 

My understanding.......

The TB hole originated on cable driven TB's that incorporated Idle Air Controls (IAC). The IAC is a small by-pass port controlled by the PCM which is used to compensate for idle when the throttle is at 0% (TB plate full closed). There is a 340 step stepper motor which will open and close this air by-pass port and be used to control the idle air. You tune for idle to be around 60-70. Ths allows enough steps up and down to allow compensation for normal, hot restart, AC on/off etc. On modded engines with cams, heads and large intakes, the TB plate can't be tweaked enough (set screw) to maintain the proper closed position voltage, or the IAC programmed low enough to maintain good up/down control. That's when the hole (by the way there is a formula to calculate the size, based on your idle airflow logs) is drilled to bring the IAC counts back down to an acceptable level.

In some verrrrrrrry rare cases an ETC setup would require a hole, but that is the exception not the rule. Drilling the hole on an ETC setup also precludes having to go back to numerous other tuning tables which are programmed via idle throttle position to activate or deactivate various functions..... so it is a time saver as well.

It's not the worse thing that a Tuner could do, but shouldn't have to. You have to make sure you don't go too big or TB plate can go to less than 3% at near-off throttle positions which will also screw up alot of PCM decision making.

JMHO

Ed M

 

Drilling a hole is a hack tune. TUNE the car properly and you don't do the hole. DO NOT LET them drill a hole in the TB!


Elmer

 

If hes telling you to drill a hole then he doesnt know how to tune.

 

I have no HOLE!

 

 

Agreed. I have a 402, cam, a4, etc and mine cranks and idles fine without a hole!

 

Too high a RPM setting could max out your IAC motor on cold start..... so we modified the throttle plate Since there is no Idle air control motor on the C6...... your tuner should be able to fix your idle with HPTuners. (provided that there is no vacuum leaks & etc.)


The drive by wire should not require a hole in the throttle plate. HP tuners will allow your tuner to fix the idle. With the old cable system you could easily close out