Secondary Air Pump: Filter Ingested. Downstream Damage to Valve?

I have a '14 not an '11. If water splashes onto the filter, I am somewhat sure that it does not immediately evaporate. It is possible that it is there when the pump runs at shutdown. But, it is just a thought followed by plan, if it makes no sense to you then for goodness sake, don't do it.

 

Ok, put everything back together. Check engine light is now off but the pump wasn't running at startup. I think I need to wait 8 hours for another true cold start.

 

I don't know where my head was at when I posted that. I was talking to you but referencing the OP and just mashed everything together. I took a break from working on my CPI Green Belt online and somewhere between statistical analysis and central tendencies I apparently left a little bit of my brain behind. I'm still correct when I said that you shouldn't have an issue with the filter ingesting water. Given how the system works and for how long it runs, it doesn't pull in a lot of suction. Definitely not enough suction to pull moisture through the filter. If you're curious, open the hood while someone starts your motor, you'll be able to hear it running for a bit if you position yourself near the pump. Since you have a 14, you'll also hear it running after a short time has passed after you shut your truck off.

The issue with the system lies within the weak foam filter that deteriorates with age falling into the impeller of the pump sucking bits of foam into the reed valves. As you know, removing the fault potential by installing the exterior filter still provides a filter media for contaminants that may be floating around in your engine bay. Any ingested moisture would be evaporated by your cats/exhaust blow-by gasses which would still be minimal. If stationary water was to reach the point where it was being introduced, water would be pouring into your intake (unless you have a snorkel). With all that said, you'll find it very difficult (not impossible) to splash water up there through daily driving and mild trail use. After heavy rains on soaked roads after about 30 min of driving from work to home, my engine compartment is clean as a whistle (albeit dusty).

Edit: shamelessly stole from this post.
If you're really feeling froggy, you can look at getting one of the covers as pictured below to provide a bit of extra protection incase you're not the type to raw dog.


-J

 

Whew! That looks pricey! Sooo Sorry OP. I did the UNI mod about a year ago on my 13. I did not put the cover back on, only plan to put it on during winter. Don't forget to replace the UNI filter every 2/3 years!

 

Haven't spent any money yet, other than the uni filter and cover, which I plan to add. Cleaned our the pump and top of the valve (will post pics later). Both functioned when connected to the battery, and had proper resistance at the connector terminals. I'm hoping the check engine light was just because the pump was clogged.

 

I still have my original foam filter. I bought a Briggs and Stratton green foam filter with same thickness and cut out a duplicate and installed.

 

The pump runs at startup only when it is 40 degrees or less. When it is over 40 degrees it doesn't run at all except for shutdown. That is how the Hewitt Bypass works it makes it appear to be over 40 degrees at startup all the time regardless of the actual temperature.

 

There is no external Relay for the Pump. Power goes like this:

50 Amp A/PMP Fuse in the under hood fuse box >> Air Injection Control Driver >> Injection Air Pump >> Ground.

50 Amp A/PMP Fuse in the under hood fuse box >> Air Injection Control Driver >> Air Switching Valve >> Ground.

What controls when the pump and valve operates is the ECM (Engine Control Module) which sends trigger signals to the Air Injection Control Driver Which is located on the Passenger side fender well area. Which in turn powers the pump and valve when commanded.

 

Ok, interesting. I'm in Phoenix, so I won't be able to test the sub-40 condition for another 3 months or so Check engine light is still off for now, so I guess I'll wait and see.

 

Keep us updated.

Thanks.

 

While I was cleaning out the pump, I decided to clean out the top side of the switching valve. I wanted to post some pictures here in case anyone wants to try this in the future.

The solenoid side of the valve can be removed without removing the entire valve body. You need to disconnect the air hose running to the pump, the air intake duct, a vacuum line leading to the switching valve, and the electrical connector which controls the valve (hidden in the picture by the intake duct). Then remove four T25 screws. These may be a little sticky at first.



The top of the valve should then pop off (with a little prying with a screw drive or a few taps of a mallet). Under the solenoid portion of the valve is a reed valve which checks exhaust from backflowing into the pump when the solenoid valve is open. There was some carbon on the top side of my reed valve and some small foam fragments to clean out (with many q-tips soaked in alcohol).



You may need a mirror to see the side of the reed valve that opens (mirror placed closest to the passenger compartment to look towards opening facing front of truck). I really had to work to get all of the little foam bits off the edges. You want to make sure the reed valve fully closes so exhaust doesn't flow back and melt your air pump. The clean reed valve:


I forgot to take pictures of the solenoid side, but there is a piston that actuates in response to voltage to open the valve. This youtube video, https://www.youtube.com/watch?v=UupDDl6RJ7U&t=394s, shows the valve disassembly and solenoid side pretty well. It seems like the entire reed valve might just be slipped in between the two parts of the valve body, meaning you could just pull it out with a pick set an clean it--I didn't realize this at the time so I didn't try.




I cleaned both sides of the solenoid side of the valve as best as I could using a vacuum and compressed air to remove foam fragments. You can energize the solenoid with 12v to test actuation and to clean it. After everything is clean, reassemble, hand tightening T25 screws, reconnecting vaccum tube, electrical connector, pump air hose, and intake duct. Any foam fragments leftover should now be on the exhaust side of the reed valve and hopefully combusted (or yo could try removing the reed valve). Best case, you've saved a few hundred bucks on paying the stealership to replace the switching valve because of a little foam.

Hope this helps some future Taco owner who gets one of these check engine codes and a nasty repair estimate.

 

Excellent follow up and post!

I'm sure it will help many.

 

Good post and good info from Jimmyh on how the system works. I have a 2009 and I thought the pump operates on any cold start, or most, and not just below 40F. I'll have to pay more attention and will try and remember to update. After seeing the thread on this a few years ago I removed the stock filter, which looked fine and not dried up, and added the uni filter; I don't need a $1000 problem that I can easily, and cheaply, eliminate happening. No issues, and I drive it offroad with stream crossings, it's been in torrential rain, etc. The system can obviously deal with minor moisture because if it's 100% humidity, it's getting moist air injected.

 

Hi! I just did this process AND then found this thread. Can you give an update? Did your truck give you anymore issues related to this valve and pump?