Michael

When I took out the pump to rebuild, I took the ACV out to replace and learned two things that was never discussed in this forum. I know most of you just plug up the hole for ACV but I wanted to keep the function.

The reason why the ACV fails is because there are three o-rings inside the valve, which I think becomes brittle and fail due to pressure in the pump. There was a guy in the forum that claim that he can rebuild the ACV but I am not sure how to take that plastic portion off gracefully than to replace those three o-rings. The best thing to do is buy a new ACV to replace.

Another is that there are two bunny ears on the plastic piece where one connects to intake manifold and the other to air duct. I think it matters which one get connected to where. If you look at the inside of that plastic piece, one bunny ear has a hole in it that goes through and the other does not. Also out side has different marking to note the difference. One side has square mark on it. So one ear must connect to a specific source. I am not certain which one goes where. Does anyone know which is connected to where on your LS?

RA40

iTrader: (6)

Nice to see that. My mechanic rebuilt the pump and this part was included in the rebuild. My PS is still good though I am noticing some fluid migration so I will be in the swap this out soon.

Michael

Would you be able to check the vacuum hose connections on yours and report when you get a chance. That would help me a great deal.

Although the alternator is still works fine, I also took it down to rebuild as there were stains from leaked PS fluid.

Michael

ACV is a $90 part.

Aeok18109

i didnt care enough to try and rebuild it on my 92. i spent $1.35 at napa for a drain plug that matched the thread pitch. smeared a line of the AISIN black goop i used on the water pump/oil pump on the drain plug, and cranked it home into the port. i have not see a drop of ATF leaking from the PS pump. i also capped off the vacuum port on the intake manifold and the intake tube. my steering feels no better or worse. just no more giant cloud of white smoke on the car and no more fire at stoplights.

RA40

iTrader: (6)

Mine has fresh vacuum hoses. The prior ones had split so the loss of vacuum was part of the drop in MPG. Since the change, I've noticed the fluid migration around the ACV and on the hoses.

Michael

RA40,

I meant that there are two bunny ears on the ACV. Which ear goes to where? If you look at the ACV bunny ears, one side has flat notches distinguishes from another ear. Which ear connects to intake manifold on your LS? Can you check that for me if you can.

timmy0tool

iTrader: (7)

so you have essentially "break" the valve to get to the o-rings? good work on the info, and trying to keep the valve operational.

UNCNOR

iTrader: (1)

What is the ACV? Does anyone have the Toyota part numbers?What should be replaced,in the same area, when the PS pump is repaired or repalced?

Amskeptic

Idle air valve connections can be attached however the ports line up under the hoses at the time of installation.
Colin

Michael

ACV stands for Air Controller Valve which is a valve that is installed on the power steering pump to control the idle when steering in low speed to prevent the overload to the engine and stalling.

Part number for the ACV is 17630-16040 and cost about $90~$100. You will see a heated discussion on the topic when you go to the power steering bible thread. Many LS owner have decided to eliminate the idle control feature for two reasons. One the valve is too expensive and has very little function. Without an ACV on power steering pump, does not affect the engine idle that much or engine does not stall without the ACV. Two, the part is error prone and and causes many problems such as power steering leak and causing white smoke from your exhaust. You can use small stubby bolt to plug up the hole after ACV is removed. There are many discussions on how to do this on this forum.

For my power steering pump, it was mostly leaking from the ACV area. A quick fix would be to just remover the old ACV and plug up the hole, but I have decided to rebuild power steering pump. So the pump is removed and I am not plugging up the hole but replacing the ACV to keep the function alive.

dveneman

"So the pump is removed and I am not plugging up the hole but replacing the ACV to keep the function alive."

Gene01

^ Good one! :-)

dveneman

Did you get the ACV hooked up and working Mike?
Sorry, I do not know which vacuum line goes where.
Does my '98 have this valve?

Michael

Here is what I found out about the ACV:

The reason that the ACV fails is because the o-ring and the plastic construction at the top (bunny ears). This valve works with fluid pressure and as o-ring ages, it becomes brittle and fluid starts to leak. This is an internal leak to your air intake system. Also the plastic becomes brittle and is causing the fluid to leak externally.

This ACV cannot be rebuilt as the plastic has to be broken off. You cannot use an old ACV from junk yard as this o-ring problem would still be the problem sooner or later. This part is not design to be able to rebuilt. One that is made out of metal would not cause an external leak but still will have fluid leaking into your intake system.

Hose connection matters as the notched side (left side in the picture) of the bunny ear will connects to air-intake and the other one connects to intake manifold, on top of engine.