I just got my first 99 prelude (bb6) , long story short the guy effed me over with a bad engine, ive slowly fixed it as I can, and now ive learned the secondary butterflies dont move at all when I hit high rpms, Everything is connected and all vaccume lines Are in the right places , idles fine and no cell codes pop up, its just super slow at take off....only thing that I can think of is the selonoid not functioning properly or the iab diaphragm is busted because when I manually compress it it makes a squishy sound almost like theres a lil fluid in it but I wanna assume theres a leak in it that doesnt obviously allow it to compress .... any help would be great

 

What ECU? Stock? If you have access to a multimeter you could test the input to the IAB vacuum box and make sure it's triggering there.

 

Sorry for the late reply, im assuming the stock one I havent personally checked, but the car is pretty much completely stock, I can get a multimeter but I wouldnt know where to use it, I did take my my whole intake off and completely stripped and cleaned all the gunk and oil out, idles smoother but stil butterflies arent closing...since the car was owned by pretty much someone who didnt do maintenance on it all could it be that maybe the silenoid ports got plugged up??? There was an extreme amount of gunk behind the throttle body and entire manifold too

 

The butterflies are closed until you hit vtec, then they open.

How do you know they aren't opening.

You can apply direct battery voltage to the iab and it should open and then click when let it off.

You may be thinking something is wrong when there's nothing wrong here.

 

Im pretty sure vacuum is what keeps them closed until you get higher in the R's. So if it fails they would be stuck open, that way you arent choking your engine.

I have a spare intake sitting around with IAB's I can crack open to take a look if need be.

Also many people take the IAB's out and just add spacers. It just relocates some power higher up, and its not "hurting" the engine by any means.

 

[QUOT,E =holmesnman ony;49671016]The butterflies are closed until you hit vtec, then they open.

How do you know they aren't opening.

You can apply direct battery voltage to the iab and it should open and then click when let it off.

You may be thinking something is wrong when there's nothing wrong here.[/QUOTE]



I thought they were supposed to be open all the time because when I took of the manifold Apart they where open.and I manually rev up the car from the engine bay and I don't see any movement on the throttle body butterflies from the outside of the manIfold.so I guess no vacuum is being ran through those lines

 

Thats what I thought , but when I turn the car on simply rev up the car up to 5k I see no movement at on them, would running the line straight from the manifold to the iab do anything, or harm anything?

 

just feel the diaphragm as someone starts it up they should close from vacuum

 

I thought they were supposed to be open all the time because when I took of the manifold Apart they where open.and I manually rev up the car from the engine bay and I don't see any movement on the throttle body butterflies from the outside of the manIfold.so I guess no vacuum is being ran through those lines[/QUOTE]

They appear open when the vehicle is off but once the engine is on the vacuum sucks them shut. I took out all my butterflys for my high end power.

 

yes you are correct when the car is off or at a equal pressure inside the motor and atmospheric or under boost they should be open. the easiest way to check is look at the arm controling them and memorize the position. then start the car once it is idling(which should be very quick) the arm should move approx 90*. this would indicate they are working properly. i also deleted the butterflies for higher end power and flow, i recommend it because you will only lose a few lbft of torque. i was at 280lbft at 4800 and dropped to 273 at the same rpm, but gained 11 hp overall by using the blacktrax plate.

 

I heard about the Blacktrax spacer AFTER i had my buddy shave my stock piece at his machine shop. I heard theyre discontinued though.