Hole in throttle plate?

[JerrySab]

Grabbed a throttle body from the junkyard to harvest the gas pedal cable and linkage, and noticed it has a 1/8”ish hole in it. Letter S is inscribed in the plate as well. Mine has no hole and letter B. Seems like hole would cause problems but I’m curious if it’s from factory or others.

 

[superj]

Thats the old school way of idle setting.

Notnsure what it means on newer vehicles though

 

[JerrySab]

Thats the old school way of idle setting.

Notnsure what it means on newer vehicles though

Lol yea just bore a hole into the thing. It looks factory but I’m suspicious

 

[rusty ol ranger]

Ive seen vehicles with a hole like that but cant recall what they were and have no idea why

 

[Curious Hound]

If you're too lazy and cheap to fix the IAC.

 

[RonD]

Usually has to do with different types of Throttle Sensors(TPS)
You want TPS to be under 1volt throttle closed, 0.69 v to 0.99v is spec, 16% to 19%(of 5volts)

On a warmed up engine with IAC Valve unplugged you want the engine to idle at about 600rpm, you want this so engine won't stall if IAC fails closed

There is a screw you can adjust to set throttle plate at idle, anti-diesel screw
So you adjust it for 600rpm with IAC unplugged
Then check TPS and its at 1.4v
So you adjust TPS, but either there is no adjustment or it can't be adjusted to go below 1 volt
So you adjust the anti-diesel screw to lower RPM, but even with engine barely running at 450rpm TPS is still 1.2v
So what can you do?

Drill a hole in the throttle plate
This lets in a bit more air so engine idles at 600 and TPS is under 1volt

The hole in throttle plate became factory standard on most engines as TPS became less adjustable, lol
And anti-diesel screw also went away over time
Because lets face it, if its adjustable, a DIYer WILL adjust it, and screw it up , pun intended

 

[JerrySab]

This writeup is as legendary as the pun. Thanks @RonD as usual.