PCV Valve and your Car's MPG

I've learned about the PCV finally. :) (often called PCV valve, or positive crankcase ventilation valve).

If you're getting black on your air filters, maybe all in one area? Perhaps near where the PCV connects via a hose to your air filter? This means your PCV is fouled or "broken" and is being a negative flow instead. I've seen that a lot in Toyota Corollas or the Geo/Chevy Prizms**, more than just mine, so I thought to pass that on.*

...I tried cleaning mine, if the labor wasn't free buying a new one is cheaper. 45 minutes of banging on the PCV valve (with my hands only) against rags, using break cleaner on it, etc., I got the entire life of the car's cake of oil and carbon out.

Next time, I'd leave it to soak in gasoline over night, probably would have been easier.

I failed to do one test so I need to get back in there. If it rattles when you shake it, you should be good. (this was probably possible earlier in the cleaning, but I thought it best to have less goop to prevent a faster re-clog.)

Finding your PCV valve...unless you want to YouTube it ;) there's a new channel on YouTube that I'm fairly unimpressed with that helped me find it (so sorry, I don't think I'll have luck finding the video to give credit; kind of rude of me maybe, but sometimes helpful information isn't in a glamorous place). There are two tubes off your valve cover. One that comes at you if your at the front of the car, and one that points to the driverside. The driverside one has is your PCV valve.

If it has it's original clamps it's easy to pinch it and pull the hose off. If it's hard or cracked it should be replaced. The PCV valve can then be unscrewed with a 17mm deep socket or box handle wrench. Be sure to have some teflon tape to put back on the threads before restoring it in the car.

A quality Toyota PCV is all metal, and if you're willing to clean it, I suspect it's possible to be a forever part. If you chose just to replace it, at least see if it rattles first, it's fine, don't replace it. I've seen plastic ones for sale for our car on eBay that cost about what the metal one would, aftermarket ones are fine, just don't go plastic.

The PCV threads in, but has multiple pieces of rubber around it even where you thread it into the valve cover; replace any that are bad. I spotted everything for sure that could be bad on ebay for cheap, except maybe the tube that goes from the PCV to the throttle body. (take it to a local parts store to match the INNER diameter if not).

*Ooops, I think that means our PCV system can't foul the air filter...maybe I need to look at my brothers 7th generation Corolla/Geo Prizm again**. This part of my information is more general to cars maybe than just to ours. I learned most of what I did about PCV valves from Briansmobile1 channel on YouTube.

Saved for last an explanation of what it does? lol, you can watch Brians video on it, or read my regurgitation:
See, engines sometimes have vacuum on your PCV valve and sometimes it has pressure. When it has pressure, unburnt gases from combustion sneak up under your valve cover and modern cars for better emissions send that through the PCV valve back to the intake so your engine can burn it off (arguably more efficient on a car's MPG, especially on bigger engines). Older designs took care of this pressure problem with a filtered cap that doubled as your oil cap.

When the "pressure" or vacuum is present in an the valve cover the PCV prevents air from coming from your intake into this part of the engine, which is then a vacuum leak (definitely reduces your car's MPG and deserves it's own article). Without this valve functioning correctly, the pressure build and builds, and will help even more unburnt fuel and exhaust past the piston rings and down into your crank case. Piston ring blow by reduces the viscosity of your oil over time. And that can be really bad news for the longevity of your engine. If this is in addition to worn piston rings and/or the bore, then your engine can really be worn faster than it needs to be.

(Severe blow by can push out the oil dipstick, if you have the regular habit of checking your oil like you should, and it keeps being pushed out, uh oh. Even if it doesn't push the dipstick off, this is a good way to find a worn engine to not buy a used car because you know now about problems with lots of blow by.) Check out my article about Synthetic Oil Controversy.

**Note:
1998 to 2002 is the 8th generation Toyota Corolla/ Chevy Prizm
93? to 96 is the 7th generation Toyota Corolla/Geo Prizm

by AutoBravado

O2 sensor ground, is it rusty? Make it easier to remove for the next guy....that might just be you.

**Sept 22 update:
Original article:

O2 sensors being grounded by the exhaust, is a concept for 1 wire O2 sensors. 4 wire O2 sensors are wired with their own ground and are not grounded by the exhaust.**

I hadn't thought about checking if the O2 sensor was cleanly grounded. Cleaning up rust always helps O2 Sensor Mod and Diagnosis)with a good connection. Yes, anti-seize. When I was early DIY rather than nearly a technician I installed a new O2 sensor, up river, and got my 1999 Chevrolet Prizm running nicely again (same as 1998-02 Toyota Corolla). The Chevy wasn't that rusty then. Now....until I own an acetylene torch or replace that manifold that O2 sensor better not fail. So rusted in (I can't take the down pipe off my manifold until the oxygen sensor is out of the way. Thankfully just replacing one of the springs cleared the exhaust leak ...still wanting a new doughnut gasket in there, but don't fix what isn't broken, it runs soooo much better). . . So yes, use anti-seize but don't get any on the sensor! (8/23/15 update: The aftermarket Bosch oxygen sensor appeared to have a normal oxygen sensor socket install, but it actually includes a flange with 2 bolts. It's an interference fit with the down pipes. I've made a video with the solutions! I got back to a OEM Denso which you can see doesn't have a nut next to the flange, which confused me into believing it wasn't removeable.)

Anyway, I just meant to say that only 8 years ago I installed the Bosch oxygen sensor and I wish I knew to put in anti-seize. The rust really isn't that bad but it's enough. I destroyed my harbor freight oxygen sensor socket...may have already done that a few job's ago that I worked around not removing the oxygen sensor. I now have a much more expensive Powerbuilt socket (never in water, quickly rusted. :p - got it super cheap on Amazon, maybe it was a Powerbuilt knock off). I haven't bought a lot from them, but whenever I break an inexpensive tool, I replace it with this brand and I never have a problem again. My new Powerbuilt O2 sensor remover worked brilliantly. It's removing all the oxygen sensors that I thought were rusted in badly, almost easily.


The last Bosch oxygen sensors I installed on my mom's 1999 Mercury Sable ran okay...but with them all new it ran sooooo much better (Same as 1999 Ford Taurus). I was surprised that the down river O2 sensors helped it run better....I guess the car's willing to run a little richer for some punch when it's not dirtying the environment? I might have imagined that part of the improvement. Bosch includes the perfect amount of anti-seize on the O2 sensor threads now. I had to love them for that little touch.

And remember, don't blame an oxygen sensor or a catalytic converter for an exhaust leak. I have a live scanner now and my new cat gave me 50% more horse power (possible to find out using a torque app and some open freeway, gps confirmed *HP as long as you report the weight of your vehicle accurately) and almost removed the condition of the rear oxygen sensor voltage switching up and down too quickly. That shows on my live scanner ...sign of a bad cat? Sure. The catalytic converter does a lot better, but you can't have an exhaust leak before the cat and know for sure if that cat is really bad without checking upstream before you finish your diagnosis.

The old catalytic converter nearly showed the same reading before and after the catalytic converter indicating that it was almost doing nothing for the car. Need more analysis for how O2 sensors should be running? Check out my article and video on the subject. Here's a link to O2 Senors, The 4 Stages of Death.

by AutoBravado

Weapon R Dragon Intake Review

I recently purchased a Weapon R Dragon Intake for my 1999 Chevrolet Prizm. To give you some history, my choice for this upgrade was different than you might think. I didn't just go in to get a short ram intake because I wanted an upgrade. About 3 years ago my car got smashed and and I had to replace 1/2 of my headlights and signal lights...not to mention my bumper. ;) A had a large canister inside the bumper that was supposed to help get some cold air into the car that broke and could not be put back in. Seeing as how the whole system still looked sealed from the weather, I counted my lucky stars and left a gaping hole that could gulp cold air into my car rather than sip through 5 tiny holes that the canister breathed through.

A couple months ago, I noticed that my wheel well was getting less sealed to the bumper and I was risking Hydro-lock. Hydro-lock is where water goes into your air intake system, combines with the fuel/air mixture and doesn't compress - water doesn't compress - and "BAM!" Your engine is broken and will often need replacement. So, terrified, knowing I was coming up on a typically rainy drive soon I needed to fix this situation fast.

I didn't even want to figure out how to replace the air canister. I didn't really know what it was called and suspected a very high price at the dealer or no availability for a part since the dealers don't sell much past 10 years. So....I went for the fix and upgrade replacement Weapon R Dragon Intake.

The Weapon R Dragon Intake came in a record fast time, a day before my road trip so I didn't have to spend valuable driving time on installation. Quite excited, I was in my car clothes within minutes and I was installing it.

I immediately noticed the extra loud noise that was new to my car. Everyone said online that the Weapon R Dragon Intake was the loudest intake on the market. (Most seem excited about that.) This worried me because I love performance but I don't like things being too loud. Turns out, once it warms up, it's pretty quiet. Plus, I really only notice the sound of the Weapon R at low speeds.

I immediately noticed that my 2.5 inch opened exhaust was louder, and that was driving gentle, since I'm all about getting the best car mpg possible, I was excited that this was a sign that my car was getting more air moved through it, dragon style :). On my trip, I had to go over mountains and I quickly noticed that when I came out of overdrive for these mountains that instead of my car sounding like it was working hard, the hills sounded natural.

Two days before my trip, I lost valuable preparation for my traveling installing the Weapon R Dragon Intake, I made up for lost time and drove faster. I usually notice a drop in car mpg when I do this, but my car mpg stayed the same even though I was driving faster. I'm not much of a speeder, I just more frequently did 80 in the posted 80 mph zones when I more often go about 75 because I get better mpg that way.

The short of it? I notice some areas where I believe I have more acceleration. It's hard to tell when I just replaced the valve that makes my 1999 Chevrolet Prizm have it's year 2000 motor with VVT-i fully functional. This valve syncs up the oil flow in the valves based on the RPM of the engine based on what the Cam Shaft Position Sensor is telling the engine what to do. This already opened up a lot more power 2 weeks ago, so not being used to that I can't really tell you. I haven't seen enough car mpg numbers to report yet, but when I do, I'll do less of a story and more of an article on my main autobravado website.

Car mpg numbers included now! Weapon R Dragon Intake Review - final review?

*Note: 1999 Chevrolet Prizm is the same as a 2000 or 2001-02, except that my 1999 Chevrolet Prizm has a 2000 LSI engine with improvements not available in 1999. Except the one improvement of a variable valve timing (VVTi), it's the same engine and parts for anything you'd replace except in association with those valves. This was during a time that Chevrolet and Toyota were in a joint partnership and made the car together, so it really is a Chevy and a Toyota, a 1998, 1999, 2000. 2001, or 2002 Toyota Corolla are the same as well.

Add snow to the AutoBravado car for extra beauty. :)

Written and produced by AutoBravado.