Secondary Air System / SAIS Replacement Info and Instructions

If I understand correctly, most or all of these kits simulate a healthy system, sending the "expected" inputs to the ECU. If your inspection is purely computer-based like it is here in GA, without any type of visual/tamper detection as part of the inspection, it should be invisible.

It varies from state to state whether or not you'll have a more in-depth inspection. And there are varying levels of SAIS bypass kits ranging from "really damn obvious" to "extremely easy to conceal".

Like, the 1st generation of the Hewitt kit, to me, is really easy on the install, but a trained inspector could probably find it if they knew what to look for. The 2nd Generation of the Hewitt kit is far more concealed, but requires popping out your dashboard and soldering onto 3 wires plugging into the ECU.

Ultimately, YMMV. I think it depends on your level of comfort and the severity of your inspection. There's at least one, maybe two guys from CA on here who've installed the bypass kit and made it through the CA inspection process just fine.

 

We have SMOG in CA and I passed.

https://hewitt-tech.com/product/sec...47h8/?sy=2006&sm=Toyota&smodel=Tundra&se=4.7L

 

Great Thread and hats off to @wandering_boy for detailed replacement documentation! My only input would be if you do the repair and go through all the effort to remove the intake please please please use Factory/OEM parts. Aftermarket Parts are cheap for a reason and see way to many owner cut this corner and end up paying more in the long run. If anyone has questions about the Bypass Please do not hesitate to contact us.

 

All switching valves and the pump were from Toyota and GM direct. I feel like for the rubber intake gasket is a OE replacement. No Cheap stuff here. But absolutely a good tip for anyone who does this. Thanks for the input. always trying to make my instructions better. If you have a good link about bypassing besides what I have. Please feel free to PM with them.

 

You still pass smog but since technically it is an emissions control device. So it does technically legally make it unsellable as a smog-able vehicle. I can't remember what the code is but its either in the carb or CA dot Codes. But it passes and I certainly don't don't give a F. So why tell the next dude.

 

So, I want to verify I am reading all this correctly, an 02 does NOT have the air pump or any of these valves, right?

I am chasing down a vacuum leak that makes a high pitched whistle, and it is a pain... replaced most of my hoses with off the shelf tubing and tried to seal the ends up on the tubes that are factory bent and flared that I will need to order.

I have a question if anyone can help out with these specific symptoms: on start and when running, a high pitched reedy whistle sound is heard, cannot find source or pinpoint which side of engine but *seems* like drivers side. When I pinch or jiggle vacuum lines on either side of engine, the noise will subside or stop temporarily. Revving engine seems to reduce it or eliminate it until I let off gas but it could just be drowning it out. Whistle persists for about 10 sec after turning engine off.

Any help would be greatly appreciated.

 

Correct, '05-'06 only, VVT-i models.

Quite likely intake manifold. Let's ask @bmf4069 since he's already gone through this with his and described very similar symptoms IIRC.

Only use OEM manifold gasket. Trust on this.

 

Intake manifold? That is something I have not considered yet. I have been eyeing the charcoal canister as the culprit, but this helps, thank you.

Is that gasket fairly simple? Or is it more like a valve cover gasket (which I need to do sometime and have been reading about)?

 

Mine was backfiring pretty bad, but my gasket was completley blown out. @Shift Happens it wouldn't hurt to try to listen under the intake. It's very possible your gasket is bad.







As @shifty` said, OEM would be best. This gasket was from RA and is maybe a year or 2 old.

 

Oof. Man, I don't think I knew that part of it. Yikes!

 

So I've had my CEL going on & off since installing the bypass kit.
Hewitt has been 100% solid on customer service, . . . I'm the one who has been lagging and not getting back into the harness to triple check my connections.
I suspect I left too much slack in the bypass harness when I soldered up the wires.
Light comes on for a day or so, then goes off for a couple weeks. Weird.
So my smog cert was due, and the light CEL was 'off' so I said, F-It and went for it . . . passed just fine.
I'll report back when I get off my arse & take another look at the connections & take some of the slack out of the wires.

 

So dumb question for y'all...

It appears all this is to correct codes caused by the SAIS system failure. If I have no issues do I just run it till I do or is there some preventative stuff I should be doing?

 

There is nothing you can do preventatively to avoid an SAIS failure.
However, I seem to remember that in 'certain scenarios' one (or more) of the switching valves/ solenoids can get stuck in an open or closed configuration, which requires you to add an additional component to the Hewitt bypass kit after the fact.
I know this is a 'vague reply' , maybe someone else will jump in and explain it better.

I know this sounds ridiculous, but a 'safer' way to avoid the problem is to install the bypass kit before the system itself fails in the first place.
Yep, fixing something that isn't broke . . . . Yet.

 

@HewittTech01 ^^^^^

 

Yep if one of your valves sticks open you have to install blocking plates on the exhaust manifold at least on my 07 not sure on 06
also stuck open valve puts truck in limp mode so you have to repair or bypass

 

Unfortunately there is no maintenance for your SAIS. You just have to wait until it shits the bed. Unless you want to proactively replace things. The check valves that connect to the headers are the most common problem as the heat of the exhaust causes everything to rust up. Nothing you can do about that. It's just a law of chemistry.

 

The trick is, just don't make the mistake of studying chem like I did. Ignorance is bliss.

​

 

I've only done high school chem and basic chem in college. It has ruined my life. lol

 

Full year of chemistry in high school, a couple semesters of inorganic chem in college. It was literally the only thing I enjoyed in college before taking 'a semester off'. College wasn't for me.

 

Well said and pardon I am late to the dance. As you will see plastered all over the forum and inter webs the SAIS is Failure Prone. There are a few advantages to installing the Bypass Kit as a preventative measure. First, there are certain SAIS error codes that will put the truck into Limp Mode, specifically "Valve Stuck Open" fault codes P2440 2442. When the truck goes into Limp Mode your performance and acceleration will be governed and luck to get up to 35 MPH. This would be terrible if you take long trips with your truck, travel off road or regularly tow. Second, if the truck is driven for long duration or you repeatedly clear the codes this expose the Pressure Sensor Inside the Air Switching Valve to exhaust. Exhaust can damage the Pressure Sensor. The Bypass Kit require the Pressure Sensor to be in good working condition to operate as engineered. In the event of Pressure Sensor damage then Addons to the Bypass Kit will be needed to clear codes.

So you can wait to the SAIS components fail and install the Bypass Kit. Or save your self some trouble and install proactively. Below I have included a few thread we posted about the SAIS and our Bypass Kit. Do not hesitate to contact us if you have any questions.

What Does the Secondary Air Injection System Do?
https://www.tundras.com/threads/what-does-the-secondary-air-injection-system-do.113683/
What Do My Secondary Air Injection Error Codes Mean?
https://www.tundras.com/threads/what-do-my-secondary-air-injection-error-codes-mean.113686/
How to Fix Secondary Air Injection System?
https://www.tundras.com/threads/how-do-you-fix-the-secondary-air-injection-system.113688/