ACIS system testing bidirectional techstream

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Sep 23, 2019 | 06:32 AM

jharris400

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From: GA

ACIS system testing bidirectional techstream

I believe my ACIS system isn't working, my car seems to be lacking low end power. I have tried activating it with my techstream with the "intake vsv" command and my launch diagun iv, neither tool showed a movement in the actuator. I can move the actuator by hand and my CEL is not on these tests were done with the engine idling.

I know my engine has been messed with in the past by POs, when I bought it there was dried coolant everywhere and the radiator had been replaced. Upon further research I recently found out through lexus service records that the engine had been overheated and ran poorly with the suggestion that a headgasket was bad. I assume the owner took it to an indy guy and had the headgasket replaced where the guy also misplaced a few bolts that held down the wiring loom and heater pipes. I'm thinking that guy also neglected to install the ACIS hoses correctly but it's a job that will require $50 in gaskets to check so you can see why I'm reluctant to pull the manifold.

I'm going to see what I can do with an inspection camera to look everything over but I don't have a lot of hope. I am also going to try to manually activate the VSV being that the connector is easy to get to on the passenger side of the intake manifold.

Sep 23, 2019 | 08:28 AM

weldthedif

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From: South Carolina

what does ACIS stand for ?

Sep 23, 2019 | 08:35 AM

jharris400

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From: GA

Acoustic Control Induction System, similar to TVIS Toyota Variable Induction System.

Sep 23, 2019 | 10:33 AM

weldthedif

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From: South Carolina

very interesting, never heard of this before.

Sep 23, 2019 | 08:14 PM

jharris400

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From: GA

After doing some troubleshooting tonight I found the VSV or the sub harness going to it must be open, with a multimeter I get no resistance when checking from the connector on the side of the intake manifold. Using an inspection camera I verified that the VSV was connected, no hoses were loose and the connector looked good.

I also tested the functionality of the bidirectional control of the VSV. When controlling "intake vsv 1" I can activate and deactivate the VSV which I substituted with a test light for the test.

I have the ACIS valve closed by using a zip tie on the back of the intake manifold to hold it closed, this is purely a test until the parts I need arrive. Unfortunately this means I have to remove the intake manifold.

Sep 24, 2019 | 08:07 AM

weldthedif

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From: South Carolina

might as well get your injectors sonically cleaned while having the intake manifold open.

Sep 25, 2019 | 07:52 PM

jharris400

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From: GA

I figured this topic would be over the heads of this forum. Keeping the ACIS plate closed (as it would be if my VSV worked) has netted a MPG increase and more low end power. Before I would routinely see from 22 to 23 MPG now I'm seeing mid to high 24 MPG. Keep in mind the ACIS plate should only open above 4700rpm and 60% throttle, any other time the plate is closed forcing the air to take the longer runners in the intake manifold.

I bought an entire intake manifold with every part from the ACIS just incase I run into more than just the VSV, turns out that VSV is open as well. Seems like with age and heat these VSVs fail, mine isn't just a fluke.