Hewitt Technologies - SAIS Bypass (2 Viewers)

Joined
Jul 6, 2017
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Charlotte, NC
I installed the Hewitt Technologies SAIS bypass kit today and it went very smoothly and without issue. I didn't have an issue with my SAIS but I thought this would be a good preventative measure. Here are pics of my install. I ran it along the existing wiring on the firewall and then covered it up with split loom. I installed the module on the inner fender instead of on the air box as it is completely out of the way from everything and close to the wiring harness. I did not remove the nuts from the manifold but backed them way out and simply slid the plate in from the side (I hope that is the right way to do it). I hope this helps others.

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Joined
Jul 30, 2018
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Minneapolis
Hey, about to do the same thing... Did the Hewitt come with the instructions you needed? I mean, the plug and play part is a breeze, but the extra wire has me guessing a bit. How long did it take you? What do you wish you had known before the install started? Any extra pics would be excellent. Thanks!
 
Joined
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Charlotte, NC
Yes it came with instructions with color pictures. The hardest thing was routing the purple wire in a fashion that I was happy with the appearance. You can't see mine because I used split loom to hide it. Otherwise it is a greyish wire that follows the firewall and goes behind a black plastic holder. You can download the instructions from their site Hewitt Instructions.

I recommend spraying some penetrating fluid on the studs the night before you do the install to avoid snapping a stud. It wasn't necessary for me even though I have 175k but for others it might be a good idea.

@Tak555 why wouldn't I install the plates?
 
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Joined
Jul 30, 2018
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Minneapolis
Yes it came with instructions with color pictures. The hardest thing was routing the purple wire in a fashion that I was happy with the appearance. You can download the instructions from their site Hewitt Instructions

thanks. I tackled this last night, and it really was fairly straightforward. My biggest challenge was the block plates.That’s a tight little spot. I don’t care what those instructions say... it’s not “easily accessed from the wheel well”. 😂
 
Joined
Feb 17, 2018
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SE PDX
Going to do mine next weekend. Are you guys pulling the pump and unnecessary plumbing/wires? I'd like to lose weight and gain space wherever possible.
 
Joined
Jul 30, 2018
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Minneapolis
After clearing the codes showing a couple stuck valves, the SAIS was working fine. I probably could have left it as well and it could have gone on indefinitely. But, I didn’t want to mess with it so I went with the bypass now.
 
Joined
Sep 22, 2019
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Sonoma
Thank you for the reporting on this. I have this problem currently and I am about to order the bypass. Are you guys installing the Pump Proxy Pack as well? If so, how many pumps are on this vehicle (2005 GX)? I will need a PPP for each pump
 
Joined
Jan 5, 2009
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Redondo Beach, CA
@Tak555 why wouldn't I install the plates?

this was from another ih8mud thread... i was under the impression that the plates were more of e necessity if you have stuck open or leaking valves, and that perhaps you could get away with just the plug-and-play bypass. but clearly below, hewitt recommends installing the plates regardless.

The only concern with driving without the block off plates is if your air switching valves are physically stuck open or leaking. If they were you would probably go back into limp mode for the valve stuck open codes. Driving the vehicle with physically stuck open or leaking air switching valves can let enough exhaust flow to damage the pressure sensors that are built into the air switching valves. Most of the time the damage occurs when someone has been driving it that way for quite a while though and a day or two typically isn't going to hurt it. Again this is only if they are physically leaking or stuck open. If you can clear your codes and drive normal with just the bypass module installed you don't have to worry about this and can get the plates in when convenient. A lot of the times this is because the valve stuck open codes are caused by a failing air pump and the air switching valves themselves are OK and not actually stuck open or leaking. You will still always want to get the plates installed because they are the only thing that ensures that the valves will not leak and cause problems later down the road. Even though the bypass module prevents the system from running those valves can still leak and if they do you would have to get the plates installed and clear the codes again. It is always best to install it all at once if you can so you don't have to worry about it or need the plates later on and can't find them.

also, is this the one you got (ON SALE FOR $190 RIGHT NOW)?
 
Joined
Sep 22, 2019
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Sonoma
also, is this the one you got (ON SALE FOR $190 RIGHT NOW)?
[/QUOTE]

I ordered one today, still not sure if I need a PPP or two. I’ll try to call Hewitt and report back
 
Joined
Jul 30, 2018
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Minneapolis
Just saw you’re in Charlotte. Want to help me install this on mine sometime? 🍻 Kit has been sitting in my garage for months.

Don’t be freaked out by the install. The only tricky parts are the blocker plates — and even that is easy if you take your time and contort your hands/neck. Just follow the directions and you’ll be fine — it’s straightforward.
 
Joined
Feb 8, 2017
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SC
thanks. I tackled this last night, and it really was fairly straightforward. My biggest challenge was the block plates.That’s a tight little spot. I don’t care what those instructions say... it’s not “easily accessed from the wheel well”. 😂
The 4x4 versions do give you a bit less room than the others but still doable. I just did them on my 05GX and didn't think it was that bad compared to my 05 Tundra DC but then again I have down quite a few now for myself.

Going to do mine next weekend. Are you guys pulling the pump and unnecessary plumbing/wires? I'd like to lose weight and gain space wherever possible.
With the Gen-I kits (V36H, V54H) would require a Pump Proxy Pack (PPP) if you wanted to remove the pump but the Gen-II will let you remove it without needing any kit addons when the Gen-II is available for the Landcruiser, GX470 and LX470.

Thank you for the reporting on this. I have this problem currently and I am about to order the bypass. Are you guys installing the Pump Proxy Pack as well? If so, how many pumps are on this vehicle (2005 GX)? I will need a PPP for each pump
ALL of the 4.7L Landcruiser, GX470 and LX470 vehicles are the older style system and only have one air pump underneath the intake manifold. It is rare for the pump under the intake manifold to go bad after bypassing the system but it has happened. Typically you would only need the PPP if you already were getting a P0418 code on these vehicles. On other vehicles that have a pump or two un the fender those can go bad afterwards because water sitting in the pump motors so it is more common to install PPP to prevent those from going bad later.
 

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