A little while back I was checking out my 4Runner's engine bay, and found all of this junk mounted, and wrapped around my engine, and was curious what it was. After some internet searching, I found that it was an Air Injection Pump.
Starting with the 2013 MY 4Runner, Toyota decided it was time to Junk Up the 4Runner’s engine bay with this monstrosity of a contraption, like it has been doing for a few years now on the 4th Gen’s V8s and Tundras.
For those unfamiliar with this system, here is a decent explanation of what it does, and the problems it has.
Tundra and Sequoia $4000 Air Injection System Problem | Tundra Headquarters Blog
Here is what really bothers me about this AIP system
1. Reliability - The Pump ($600) and Valve Set ($150 x2) are failure prone, and not exactly cheap to replace. Toyota believes that the most frequent cause of the failure is if the AIP takes in moisture. This is why you hear that annoying electric fan noise for about 1 sec after your turn off your 4nr. When you turn off your 4NR, the AIP runs in reverse for about 1 sec to remove moisture from the pump. Even if this new design feature helps with longevity, the AIP system is just another set of things to go wrong, and at this point, we don’t really know how this new and “improved” AIP system will last in the 2013 4NRs. Oh, and if either the Pump or the Valve Sets fail, your 4NR will go into limp mode…
2. Junk – This Air Injection System has a bunch of parts, wires, and hoses that run all over the place, that waste engine bay space, for say a 2nd battery, and will no doubt cause obstacles when doing service on parts of the engine.
Here is a diagram of the whole Air Injection System:
Here is a pic of my engine bay, that shows part of the system:
And then there is the AIP, which takes up a perfectly good place for a 2nd battery:
3. Placement – This system was clearly an afterthought, as Toyota put the Valve Sets in a very inconvenient place. They basically mounted them on each of the valve covers, blocking access to the middle Igniters/Spark Plugs:
Driver Side Valve Set, blocking the Igniter/Spark Plug (See Red Arrow):
Passenger Side Valve Set, completely obstructs access to the Middle Spark Plug (Arrow) and it’s hose blocks access to the Front Igniter/Spark Plug:
Luckily our Spark Plug Intervals are 100k miles. I imagine that those valve sets will need to be removed, and all of the gaskets replaced when it is time to change the spark Plugs, taking a simple maintenance procedure, and turning it into a PITA.
So, thank you CARB for not only limiting what engine choices we get on our vehicles, but forcing Manufactures to throw a bunch of unreliable junk on our vehicles, and forcing us to pay for it, not only at initial purchase, but its replacement down the road.
Lovin' my 4R
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