What kind of filament did you use?

Well, the 3D printed parts certainly work and I have used it for a few days in my truck. The action is heavier which may be due to the different material or the inserts may be a bit thicker. Either way, it's not as good as the standard replacement parts so I'm going to go back to them. I also learned that the Univex rebuild kits are now available on Amazon so there isn't really a need for the 3D printed parts anyway.

3RZ Intake refresh and upgraded fuel injectors - part 1

One item I had never addressed on my 3RZ nearing 290k miles was to pull the intake system and clean things out. I took some time gathering all of the necessary parts like gaskets and o-rings and decided to take the opportunity to change out all of the little coolant hoses back in there and any vacuum hoses I could reach.

I also wanted to refresh the fuel injectors and went with an upgraded 12-hole design from Osidetiger.

Starting out


Upper manifold pulled. Pretty filthy in there along with the EGR passage.





Lower intake pulled. A lot more filthy with a heavy deposit of varnish and gum all on the inner walls.





Fortunately the intake valves look pristine



After 6 cans of brake cleaner, 4 cans of carb cleaner, a bottle of rubbing alcohol, and the demise of an assortment of brass bottle brushes, the manifolds and ports were finally spotless. I also pulled the plastic fuel injector isolators out of the head -- a gentle twist with pliers and out they came.







EGR valve cleaned out. Also cleaned the IAC on the throttle body (no picture)



Fresh fuel injector isolators and o-rings installed





Ready for injectors and reassembly!

3RZ intake project continued

Injector rail removed with OEM injectors



The Osidetiger injectors are stock flowrate Aisin of a more modern design with fully encapsulated plastic body. They also match the stock wiring harness so no jumpers are needed, they just plug right in. The kit came with all the o-rings and tip insulators needed.



They use little aluminum spacers to match the height of the OEM injectors



The injector tips are quite different. OEM uses twin holes and the Osidetiger ones use 12 micro holes. The idea is that the fuel is more thoroughly atomized when leaving the injector so it can burn more efficiently



All set up on the new rail. It's important to lube the o-rings with fresh gasoline and make sure they are seated nice and straight.



Fuel rail with new injectors installed





Replaced all of the heater hoses, including the two rubber hoses near the pass side frame rail that adapt to the rear heater, and the hoses going to the IAC and EGR. Most of these are OEM but a couple of the heater hoses were discontinued by Toyota -- fortunately Gates still makes them, such as the long heater hose on the righthand side which is not a 100% perfect fit. Changed out many of the little vacuum hoses with some Toyota cut-to-length hose.



All done minus getting the intake tube back in place



And here is the jumbo pile of old parts put back in the baggies the new ones came in, just in case I needed to refer back to one.



While I had the cooling system drained I also swapped out the radiator fan with a new Aisin unit just as preventative maintenance. The old one was in good shape but the plastic can embrittle over time so this is just for insurance.



Finally here are some impressions of the engine after all of this work. Upon first start the idle was quite high, about 2000rpm, but after a short drive it settled back down after the EFI system had time to readjust to everything. After driving ~200 miles through the mountains and freeway this weekend the idle has established a base point of about 750-800rpm. This is just a touch higher than the stock 650-750 range and I may be able to find a way to adjust it but it's a very minor issue. *4/20/23 update* Turns out my idle increase was due to the throttle cable being misadjusted. Once I gave it a bit of slack it allowed the throttle to close all the way... the idle is now rock solid at 700rpm where it should be.

With the new injectors the engine starts more readily and runs & idles more smoothly. There is a definite increase in power, 5-10% is my guesstimate. Driving up some mountain roads that I know well I found that in many cases I was able to hold the truck in a higher gear than I normally would be able to. It's still just a 4 banger of course but the power and driveability it significantly improved. Overall I am super happy with this upgrade. After a few tanks I'll be able to tell if there is a mileage improvement but I expect there will be. *4/20/23 update* It does not appear to have increased the mileage at all, just the power.

I want to note too that it is definitely possible to replace injectors without removing the intake or even the throttle body. I actually had to do this because I got one injector installed a bit crooked which caused a leak. Taking the rail off and reseating the injectors and adapters solved the issue immediately. It's a bit tricky reaching the plug of the rear injector but really not hard to do.

Thanks for reading!

So much attention to detail! Love the build.

Looks good. Great job...

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Nice work! I thought I was the only one who puts old parts into the baggies the new ones came in, I guess not .

For the injectors, did you do any special tuning? Their website says "Tuning is required for proper use."

@JZiggy , Thanks for Injector post, design change very interesting going to check on 5VZ application !

Yep, sure do!

No tuning needed. Other than a +100rpm base idle (*edit* that was just due to a misadjusted throttle cable, oops!) there is no other change to how the car runs (other than smoother and more power). No codes, no adjustments.

I think Osidetiger also specializes in higher flowrate injectors for modded setups, where tuning would of course be needed.

Nice work, man!

Regarding the fan, do you have a PN and did you replace the fan clutch, too?

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@JZiggy , I'm a fuel injector dummy - my truck has about 210K on it now, and purrs like a kitten (but will probably blow a head gasket now that I said this).

Is there any reason other than sheer boredom to consider doing anything to the injectors? I noticed that Osidetiger specializes in cleaning/refurbishing injectors, is that worthwhile doing in my case? I guess looking at cost, cleaning 6 injectors is not that much less than getting their remanufactured set.

Aisin FNT002. It may be a different fan for the V6's.

I had replaced the fan clutch a few years ago, also with an Aisin unit.

Injectors can slowly get plugged and their patterns get less than optimal, and injector-to-injector may have slightly different flowrates. I wouldn't think it's a critical thing to worry about unless you have a failure or leak.

It is a different fan for the 5VZ. Aisin FNT-005.

I am in the market for a 3rz 4runner as well. I am in Northern California.