just majorly upgraded and now idleing high.... how do i fix it?

[Simadowna119]

just installed new IC piping, new exhaust manifold (stock) and 3 inch downpipe and exhaust.... and i removed my AC belt and core...

my car was idleing at about 750 before.... now it idles at about 1100 rpm

i am wondering can i just play with the idle screw to fix my idle?... do i need to disconnect the battery first or anything?,,, or do i need to do the full BISS adjustment step by step?

 

[rEclipserGST]

just installed new IC piping, new exhaust manifold (stock) and 3 inch downpipe and exhaust.... and i removed my AC belt and core...

my car was idleing at about 750 before.... now it idles at about 1100 rpm

i am wondering can i just play with the idle screw to fix my idle?... do i need to disconnect the battery first or anything?,,, or do i need to do the full BISS adjustment step by step?

Just adjust with the biss screw. You increased the air flow, that is why you are idling higher. Just get it around 700-900 rpm and you should be good.

 

[Simadowna119]

while the car is running?, warmed up? and does screwing in (closing the gap) make it idle higher or lower?

 

[rEclipserGST]

while the car is running?, warmed up? and does screwing in (closing the gap) make it idle higher or lower?

Yes while running, yes at full temp. Closing the gap makes it idle lower because you are reducing the amount of air passing thru.

 

[EagleTSIawd]

Normally you should have the biss screw almost all the way in. High idle could also be from a vaccum leak on the intake manifold, I would recomend checking that also.

 

[Simadowna119]

well i the wierd thing is i did a boost leak test about a month ago and i didnt have any leaks... but ive had the car for a few monthes and it always sounds like theres air coming from the intake manifold/ throttlebody area.... the throttleboddy is new with new gaskets.... you guys think i should just go ahead and replace the intake manifold gasket? or would the IC pipings air flow just make that noise slightly because after i installed the 2.25 inch piping the noise got just a lil louder

im about to make a 1100 mile trip, moving to nebraska, so i just want everything in tip top order

 

[EagleTSIawd]

A boost leak test is done to check for any leaks after the throttle body so you are good there. All you need to do now is a vaccum leak test, grab a starting fluid can and spray it where ever you think there might be a leak or anywhere around the gasket area on the intake mani. If the idle drops then that's where the leak is (this is done with the car on at idle).

 

[steve]

If the car idled correctly before your changes and you didn't touch the BISS during the changes then it shouldn't have changed the idle or need adjusting (unless it was wrong before and you fixed a leak).

A boost leak test from a mount ago is no longer valid since you touched the intake system when you changed the IC piping.

Something else is letting air reach the cylinders. Start with a fresh pressure test and then once all the leaks are repaired reset the BISS.

 

[crash89]

I agree with steve, after you took off your stock IC pipiing you could have damaged a throttle body gasket and one of those COULD be leaking. I would check that first if I were you. Then do another boost/vacuum leak test.