So, if I am reading this correctly, the 06 and 07 4.7’s have the SAIS, located under the intake manifold on the back near the firewall. Either at the same time or at different times, will start throwing p1442, 45 and possibly 2441 codes (which could throw the rig into limp mode, right?). The filters used in the fan with the plastic fins disintegrates over time, allowing for non filtered air to pass through the SAIS and then into the exhaust manifold and eventually the cats. This unfiltered air contains contaminants that will eventually cause the cats to fail 420/430 codes. Just curious, the SAIS fan forces outside air into the exhaust manifold, where is it pulling the outside air from?
Because the SAIS codes will affect the drivability of the rig, it would seem that the first point to address is the SAIS codes and your solution is to, and I might be reading into this, is remove the old filter from the fan housing and install a replaceable filter. Can’t wait for the details on that.
Of course we, myself included, know that you can use the Hewitt solution which is to bypass the SAIS and install block off plates between the SAIS where it joins the exhaust manifold, legal or illegal, what this does is prevent any contaminant from getting into the exhaust and to the CATs. And yes, we know that it is not legal.
However, will either one of these options actually clear the 420/430 codes? I would assume that if you are getting these codes, your CATs have already been damaged, possibly from the SAIS, but the fix that you are talking about seems more of a preventive measure that one should take in order to not get the dang CAT codes. Once the CATs are bad, seems that the only solution to get your rig to pass smog is replace the CATs or maybe the O2 sensors which might be reading poorly.
First can I ask, that you give detail on: why you installed the block off kit. What else was done? What codes (DTC) you may have or had before and after???
Location of AI pump main switch and it's air intake port:
SAIS or AI pump and main SW, are under intake manifold near front of engine just back of radiator fan forward of starter. AI SW's BK1 & BK2 SW are on water bypass joint rear (near fire wall).
No limp mode:
These stuck closed codes (DTC) of A.I. do not put vehicle in limp mode. Nor do P0420 or P04230. We just get a CEL if DTC are confirmed. The VSC shut down as a result. Any engine, ABS, transfer case or Transmission DTC will shut down VSC. So no big deal with driving, unless you need VSC. But you'll not likely pass emission test if the inspector see CEL, for sure not if he check codes. They are all emission related DTC.
Yes: "
The filters used in the fan with the plastic fins disintegrates (one possibility) over time, allowing for non filtered air to pass through the SAIS and then into the exhaust manifold and eventually the cats. This unfiltered air contains contaminants that will eventually (MAY) cause the cats to fail 420/430 codes. Just curious, the SAIS fan forces outside air into the exhaust manifold, where is it pulling the outside air from?"
A.I. Air is pulled from:
A.I. Pump, pulls air from under the intake manifold, just behind radiator cooling fan area, from engine valley. Pump has a 1"OD by ~4" tube come out of side of it's top, which it draws air through.
End of A.I pump air draw tube, circled in yellow.
Anyone that has done a starter jobs, knows how much dust build in the valley. Add in nest from rodent, etc, it's a nasty mess under there.
I showed the aftermarket filter in first post #2. Here's rout revealed, simple right!
Took me time to come up with the routing and materials. My first thought was to rout to firewall. But this is much shorter piping, cleaner and gives easy access to replace filter. I'll be posting detail on how and where to get materials I used.
Location of A.I Bk1 & BK2 switches, along with air pipes from each of them to exhaust header.
Yes, Hewitt block off kit work to close A.I. air passage to CAT. Which then make vehicle it's on, only legal to drive off-road as you know! So once blocks in place, no air/containment can reach heads or CATs through the AI system. They place blocking plate between air pipes and exhaust headers. I understand the $500 block off kit, you must also remove intake manifold. But that is hear-say, as I do not do install them. Why not? Because, all 100 series that come to me are driven on city streets and HWY, at minimum to get off road. I understand why so many have blocked off. For one, they knew of no other solution.
A.I filter failure is one reason A.I. system go bad. Primary reason IMHO. Failure of or fear of failure of A.I. system, is why people use the block off kits. I've seen post in mud, A.I.. pump get louder and sound like turbo or vacuum cleaner just before failure. My pump sound likely that daily for a about a year, never changed. Which I found was due to filter being near total gone. So very likely many with the Hewitt block, if they look in A.I. pump, will find filter gone partially or completely.
Yes, Filter mod as PM. absolutely IMHO:
This will prevent A.I. system and CAT from damage, that is do to A.I. filter failure. Which could save thousand in repair cost.
Yes, Filter mod should be installed after we get A.I. system and/or CATs damage, if not already in:
If A.I. and or CAT already damaged caused/due to A.I. blowing unfiltered air through the system. You must correct problem that "cause" damage first thing, or problems comes back. Many have just slapped in new CAT, just to have go bad again.
Cause must be found and corrected, before fixing any issue. A flat tire from a nail, remove the nail before patching. This is especially true of CATs. In this case of A.I. filtration failure; replace the A.I. pump which comes with new filter sealed in it. Or my solution, remove factory non replaceable filter and install a replaceable aftermarket filter. Then replace other parts as necessary, like CATs.
