IAB solenoid problem

[bruno8747]

I changed the head on my 92EX and I kept the intake manifold. When I took off the intake manifold I saw that the solenoid on the black box underneath the intake was rusted and damaged so I had another solenoid from that lil box next to the battery and I used that instead and Now it dosent work. I tested the new solenoid and I hear it click and I can feel it click.

And what is puzzling me right now is that I remember that the old solenoid used to work and now its damamge and it dosent work....What could be wrong with this new one.

[accordaffair]

it doesn't work as in it doesn't control the vacuum properly? because you said the solenoid is working (clicks)

[bruno8747]

I can feel the solenoid click in my hand when I hook it up to the battery but when I plug it into the connector and hook up the vacume hoses to it dosent work. I hooked it up before and rev the car from under the hood and I dont see the butterfly's moving at all....But if I do remove the solenoid and hook up a vacume line to it, it moves as normal. I dont know if its not getting the voltage from the ecu.

[accordaffair]

Does it click while connected when you rev the engine? In other words, is it receiving the signal from the ecu and engaging at least? Try feeling for the click while manipulating the throttle. Also the box isn't broken or anything to where it wouldn't be able to hold/provide a vacuum?

[bruno8747]

I dont think the solenoid is getting the signal at all. The box is holding vacume though because when I remove one of the lines I can feel the vacume its just the solenoid not getting a signal....And it used to work before but i dont know whats wrong now.

[accordaffair]

Well I assume you are using the connector from the old IAB, not that connector from the original IAC near the battery that controlled the intake system. You should connect a multimeter to the IAB connector and rev it to 4400 or 5200 rpms or whatever rpms the ecu sends the signal. *Someone else chime in and fill in that information* The ecu will send a ground and complete the circuit, and you should get a 12v signal *I believe it will be 12v, just check for voltage*. I have an LX, but I rigged up my system after I swapped to the A6 IM. I ran a wire to my PT6 ecu, to pin a17 I think. Then I ran the other wire to a wire next to the distributor. I believe it's black/yellow, it supplies 12v.

Now all this shouldn't be necessary since you already have an EX , but what I'm trying to teach you is how the IAB works. It has the 12v wire all the time, but doesn't get grounded until the ecu supplies the ground. In doing this it completes the circuit. Perhaps a wire is severed somewhere. As I said test it with a multimeter. Check for voltage at the rpm engage point. And check for continuity along the wire to find a break if there is one.
Whew!

[xaxis360]

The solenoids may not be interchangable. They are color coded on the bottom. The one that controls the IAB is blue, and the one controlling the Intake Noise Suppression system is brown. They allow for different amounts of vacuum depending on what they were designed to control.

My IAB solenoid went bad. I had no clue until I saw that the diaphragm didn't move when I had a friend start the engine. If you don't want to buy a new solenoid, I would hook the IAB diaphragm up to its supply vacuum hose directly from the plenum. This will keep it open all the time as it would be anyways below 4700 RPM.

[accordztech]

cpmike is right on the money.

h22 iabs hook right up and will work.

but if u power it and ground it and u hear a click then it should be fine....maybe its clogged....junkyard time.

[bruno8747]

Ok today I really went out and tested everything. And still it dosent work.

Well I tested the connector at the IAB and I get the 12V signal but when I rev it NO ground. Now I went and tested it at the ECU and when I rev the engine I get the ground. So that would mean somewhere along the line there is a broken wire.

Now onto the manifold it self. When There is NO signal to the solenoid its suppose to send vacume to the diaphram rite?
Well in my case again.....When I hook up the solenoid there is no vacume going to the diaphram and its open all the time.

This is getting really confusing now. And about what xaxis360 said: could the 2 solenoid's be different?
Could one always be open to let vacume go through till it gets a signal to stop vacume?(thats what I need)
And one that is always closed letting no vacume pass and when it gets signal it starts to let vacume pass through?

[bruno8747]

My IAB solenoid went bad. I had no clue until I saw that the diaphragm didn't move when I had a friend start the engine. If you don't want to buy a new solenoid, I would hook the IAB diaphragm up to its supply vacuum hose directly from the plenum. This will keep it open all the time as it would be anyways below 4700 RPM.

You say that the runners will stay open when I hook up the vacume....But isnt the default position open WITHOUT vacume? And closed with vacume?

[accordaffair]

They should remain closed with vacuum, and open with no vacuum. The runners should be closed until the signal arrives, which will open them. The 12v wire is always connected, the ground comes from the ecu.

Let me ask this, you're saying your diaphragm provides no vacuum even when its not hooked up?

The method I used the intake air control diaphragm is to use the original intake air control electrical connector and then hook the vacuum diaphragm up to the runners. It worked perfectly except they opened too early (like 3500), because that's when that device got its ecu signal.