While trying to figure out my rough idle issues I noticed a small hole in the middle of my primary throttle valve. I compared it to a spare intake I have and the spare doesn't have the hole. Did the previous owner drill a hole in the butterfly or is it supposed to be there?

 

j9fd3s did it on peepers.

 

So based on what you're saying, the hole is not normal.

 

its an old trick to increase idle air bypass without moving the throttle plate open and exposing the progression circuit

done in desperation on ported engines that like to stall and only occasionally with win

 

Okay. Thanks. Sounds like it might be part of the idle issues I'm having.

 

what throttle did you see this on? if its a carb, then its not stock. if its EFI, i want to say there is a stock throttle body with a hole in it, however i don't know which one, i'd have to look

lmao!

that's exactly why i did it, although it didn't work to make it run on the idle hole, it did wonders for drivability! less intake vacuum = less exhaust gas gets sucked into the intake stroke. the size of the hole is a compromise, but i can make the P port idle without the brap brap... which of course is no fun at all.

 

Yeah..it's EFI. I've replaced the butterfly. It didn't help the situation but it's good to know just the same.

On another note...I did a pin probe on the ECU and found that I wasn't getting good numbers. Traced back to the fuseable link and found the one that powers the ecu was connected by a single strand of thin wire. Runs MUCH better after replacing it! Now I seem to have flooded the car...I just can't win.

Thanks for the help.