I have a 94 Prelude SI 2.3 that I just replace the valves on. After putting it back together I discovered a little black box under the intake manifold that has a couple vacume lines and a connector. One of the tabs for the vac lines is broken, and I don't know what the box is for. Anyone know what it is, and will it still be ok without the line plugged in. It runs fine like it is, but need to know if it will hurt anything.

Thanks

 

it controls the butterflies in the intake manifold (called IABs)

without it hooked up correctly, the will always be open, you will lose some low end pickup.

try sourcing another one. that tab is a common break.

 

Thanks for the info. I will try and replace it.

 

yeah unless your running a chipped OBD1 ecu(besides a P72) you want to get that fixed, your losing low end and probably not even gaining it back int he midrange since you can't tune for the increased airflow. People normally(when the can control the IAB with a chipped P72) lower the point at which the IAB's engage to get net a few under the curve ponies but you have to be able to tune for that so, yeah fix it

you should see a solenoid on the driverside of your intake manifold about halfway down it. That is the solenoid that controls the IAB's the vacuum line goes into the top nipple there, with that not connected to a source of vacuum your IAB's will be left open.

 

DC, you need the vacuum box in order for the IABs to function properly. The solenoid stays open while you're at low rpm. If you hit the gas hard without the vac box, there is no vac left in the IM, and the IABs will open.

The vac box has a 1 way check valve on it and it stores some vac pressure to hold them closed while you're on the throttle.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mgags7 &raquo;</TD></TR><TR><TD CLASS="quote">it controls the butterflies in the intake manifold (called IABs)

without it hooked up correctly, the will always be open, you will lose some low end pickup.</TD></TR></TABLE>

I just read this and got curious. I went out and pulled the sensor plug and it threw me a code 10. This is intake air temperature sensor...did I pull the wrong one? I want to know if mine are working or not. I'm running an ODBII P13-A12 on a JDM H23A (blue top). Now, my name isn't Yagamoto Sushimatakisun, but wouldn't it be better to leave these wide open on a FI engine?(I'm sorry if this is your real name)

 

I just happen to have one sitting around in perfect condition... Make an offer if you'd like.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by theresyourproblem &raquo;</TD></TR><TR><TD CLASS="quote">

I just read this and got curious. I went out and pulled the sensor plug and it threw me a code 10. This is intake air temperature sensor...did I pull the wrong one? I want to know if mine are working or not. I'm running an ODBII P13-A12 on a JDM H23A (blue top). Now, my name isn't Yagamoto Sushimatakisun, but wouldn't it be better to leave these wide open on a FI engine?(I'm sorry if this is your real name)</TD></TR></TABLE>

You unplugged the IAT, lol. The IAB connector is farther down.

FI would like the extra flow, if I was doing FI I would take that plate out entirely.

 

idk if 4th gens have this but it could be for the stock intake box under the bumper.