rpms go up if pump the brakes

[ugadawg187]

My 97 civic EX 5 speed had a CEL P0505 i think for the IACV so i cleaned it only then to have jumping idle. I replaced it with a brand new IACV. Now when you turn the a/c on you can hear the IACV click rpm's jump to 1200 but quickly fall down to around 600-700rpms. It idles at 900 rpms with the a/c off. I heard the brake booster or master cylinder could cause a vaccum leak so i pumped the breaks & it idles up. Push the brake pedal & nothing happens until you let off then it idles up & back down. Any input on this?

 

[CHILD]

That's normal with a brake booster line in use if the cel code issue has been resolved

 

[CHYEAHMAYNE]

That's normal with a brake booster line in use if the cel code issue has been resolved

Just curious, why is it normal?

 

[MistahJuice]

Brake boosters do exactly what they sound like, they multiply the force you exert on the pedal to help your brakes work properly. They do this using the vacuum caused by your engine so when you step on the brake, the idle needs to go up to compensate for it using part of the vacuum your car creates.

 

[CHYEAHMAYNE]

Brake boosters do exactly what they sound like, they multiply the force you exert on the pedal to help your brakes work properly. They do this using the vacuum caused by your engine so when you step on the brake, the idle needs to go up to compensate for it using part of the vacuum your car creates.

This happens only after clearing P0505, or is it normal all the time?

 

[civicexkid]

all the time

 

[1badej8]

its all good normal for idle to go up when brake pedal is pumped