Throttle butterfly, NHW11 Prius

[tochatihu]

NHW11 Prius of course is the 2001-2003 model. Due to the generosity of our "IFixEm", I got my hands on a failed throttle assembly. I forgot to ask him what model year it was from.

Its throttle position sensors resemble those in the accelerator pedal closely, but not exactly. The curved potentiometer tracks and wiper "fingers" are same-looking, but their connections are hard-wired, not passed through pressure contacts. Therefore it is not feasible to completely remove the lid of the "potentiometer box" (as I've described it in the accel pedal system) to perform renovation.

I cut it mostly open with a moto-tool, and applied Caig's "ProGold" to the metal wipers, and "CaiLube" to the wiper tracks. Then epoxied it closed in the conventional way. To determine if it is fixed would require swapping it into my 2001 Prius. At least temporarily the expense of that may keep me from finding out.

Along the way I also learned (as others may already know) that it is easy and harmless to open the throttle butterfly by turning the spring-loaded shaft on the outside of the throttle assembly. With it installed in the vehicle, this shaft is on the left side, under the air filter box, and quite easy to access. So for the first time ever I opened Tochatihu's throttle butterfly and looked underneath. To my surprise there is engine oil in the intake manifold. This oil has not caused me any MILs, P3191s, etc, but there it is. Further I am not aware that the engine oil has ever been overfilled/ too-rapidly filled; at least not since I have been doing the oiling over the last 50k miles. Perhaps this shows that the PVC valve can send oil "upstream". Not aware of any other potential source.

Now that I know the oil is in there, I kinda want it gone, and the PCV valve replaced also. So this may provide the excuse to get in there and test the other throttle assembly as well. Yet another $hundred or two to be spent on Prius experiments, when nothing is actually going wrong! Send your financial contributions to...

Just kidding, but if anyone else has explored this region of the NHW11 Prius I would like to hear about what you've learned.

PS, related. IFixEm also had a failed power steering assembly. We opened that up rapidly and rather destructively. So finally I have seen its potentiometers as well, but there is no obvious way to access and service them without breaking something. So power steering victims still seem to have only 3 choices: be under warranty, obtain a PS assembly (preferably late '02 or '03) from the world of salvage, or pay Toyota the big bucks.

[galaxee]

that reminds me, i need to tell DH again to take that damned steering rack out of the storage closet...

it's always the good techs that take things home and pull them apart in their spare time, apparently IFixEm does the same

[Frank Hudon]

on the oil in the bottom of the intake manifold both of our Prius has it and it's now gone. I took a piece of plastic tubing 1/8" in dia. and a piece of rubber hose cut a notch in the rubber hose and pushed it on the plastic tube then took my air blow gun and insterted the tip in the notch pointing to the end opposite the plastic tube. Then opened the throttle butterfly and sprayed CRC Clean R Carb down in the manifoled ( a fair amount of it) let it sit for 30 seconds the put the plastic tube down into the residue and sprayed the gunk out the other end with the air, air powered syphon. I don't over fill the engine in either so am starting to think that this is just a normal Prius event/condition. Will check it more often as it was about 25,000kms on both when I did it.
Edit: don't spray the stuff where it'll land on the car as it'll eat the paint. Contains Toluene