Tech tip of the week – 6/27/11 – Fuel Filters

Yep, our cars have fuel filters.  If your reading my blog you probably knew that already, but you’d be surprised by how many people have no idea.  This makes fuel filters a perfect candidate for my tip of the week.

Why should i care about a filter ive never heard of before now?  Obviously its not important!

Wrong.  Our fuel filters provide a necessary protection for our engines just like all of the other filters we have in our system.  Our gasoline engines are incredibly inefficient to start with (about 10% efficiency for your average vehicle).  Yes, its true, gasoline engines waste about 90% of their potential energy output simply by design.  So just imagine how efficient your engine is when it cant get fuel.  A clogged or blocked up fuel filter will prevent the correct amount of fuel from reaching your injectors and that means less power or worse.

By “Or Worse” i mean things like preventing your engine from starting, engine stalling during driving, loss of power, bad gas mileage and hesistation on acceleration.

…But how does my fuel filter get clogged?  How often to i replace it? 

Our fuel filters get clogged for alot of reasons.  The Number one reason being our gasoline.

Gas stations are supposed to have a series of filters (and replace them often) on their fuel pumps, but that’s not always the case.  Gas stations can get bad/dirty shipments of fuel even just due to dirt inside the fuel tanker truck that delivered it.  All these finely broken down dirt particles build up over time and clog our filters. Think about how many tanks of potentially dirty gas we go through during the life of our vehicles.   There are lots of variables such as rust, dirt from your fuel cap, and dust from the air.

Fact of the matter is, if you’ve never changed your fuel filter, its time.  On average you should be replacing your fuel filter every 50,000 miles.  However, as the car gets older and rust, debris and other contamination builds up in the fuel tank, it may help to change it more often.  Depending on the model of your vehicle, replacing fuel filters  may be a very expensive venture.  The fuel filters themselves are not usually the expensive part.  A replacement fuel filter for an e36, or e39 can run you about 15$ if you shop around, but labor can be an hour or more on some cars.  Depending on where you live that one hour of labor could mean a 145$ fuel filter replacement.  As we can see having your filter replaced year after year might be too rich for your blood, and that’s ok.  Once a year is a nice goal, but in the real world, as long as we stick to at least once every 25K- 50K miles, we should be ok.

Hope you’ve learned a little about an often neglected yet critical filter.

If you have more questions feel free to contact me via Twitter: @BimmerMechanic, or by Email: BimmerMechanic@Gmail.com

- Tim

Tech tip of the week – 6/20/11 – Batteries

Your vehicles battery is the heart of its electrical system.  Car batteries, just like portable batteries, wear out over time.  Excessive heat, vibration, and cold can prematurely damage or even kill your battery.

As a general rule, you should replace the battery in your vehicle every five years. Although batteries can last longer, they have a tendency of failing when you need them most.  The most common time of year for battery failure is the summer.  Batteries receive the most abuse during the winter, but faults in the battery tend to finally give way during the warmest months.

Here are some things you can do to help extend the life of your vehicles battery:

- Always make sure your battery is securely strapped in place.  Vibration and bouncing of the battery is one of your biggest enemies.

- If your battery has vent caps, check to see if the cells in your battery have the proper electrolyte levels. If a cell or multiple cells appear low, you can use Distilled water to carefully refill them. If your electrolyte levels are low, your battery will not properly recharge.

**Warning** Car batteries contain acid!  If you are not careful, you could incur personal or vehicular damage.  If you don’t know what your doing, bring it to a professional!

-  Keep this in mind.  Replacing your cars battery for $60 is at least half as expensive as getting your vehicle towed when it won’t start.

Fun Fact:  You car uses the battery to start the vehicle, but once the car is started, the alternator takes over to provide power for the entire vehicle.

That’s all for now!

-Tim

Fuel Part 1: Choose your octane!

“How stupid does he think i am?”

Is that what your saying right now?  I hope not.   Because if you’re reading my blog, you’re at the very least trying to learn more about your vehicle.  That puts you a step above most other motorists on the road (at least in my eyes.)

Seriously though.  How much is there really to think about at a gas station? You pull up, push the right button, and pay whatever obnoxious dollar amount the station is charging that day. It’s that simple right?.

Well.. not exactly. So I’m going to give you some tips and tricks that will hopefully save you some money. If you stay the course and read through this post,  it will be worth your time.

Let’s get started!

Octane Ratings and You.

Octane ratings are more than just a simple number on your gas pump.  Sure, you know regular is the lowest number, midgrade is the middle number, and premium is the high number, but there’s a lot going on behind the scenes. The numbers on the pump actually show how easily the gasoline combusts. Here is something you might not have known: The lowest grade of gas is actually the most readily combustible.  Shocker?  That fact threw me off guard the first time i heard it too.  Higher octane gas is required in premium vehicles because most higher end makes and models use higher engine compression. Higher compression means more heat and pressure.  If you use low grade fuel in high compression engine setups, you can get poor gas mileage, misfires, pre-ignition and even engine damage.

Just keep this in mind:  The higher the number, the less the gasoline wants to burn.

Here’s another thing you might not have known: Mid-grade gas is just a mix of regular and premium.  There is absolutely no reason to use mid-grade gas.  First of all, you are at the gas stations mercy when you select that middle grade of fuel.  Why?  Because you are trusting that the gas station has properly calibrated the pump that mixes your fuel together.  You might be getting 75% low-grade and 25% premium!   Secondly, name a vehicle with a manual saying, “Use Mid-Grade Fuel ONLY”.  Yea exactly, there isnt one.  If you have been buying mid-grade assuming it’s making your car run better, but doesn’t cost as much as premium, stop.

Here are answers to some of the most common misconceptions:

 ”But but… higher grade fuel will make my car have more power!”

I hear this all the time and this assumption could not be more wrong.  Using a fuel grade above what is required on non-modified vehicles can actually decrease power, decrease MPG, and create MORE emissions!  Remember octane has nothing to do with “power”, and everything  to do with how likely it will combust/completely burn.  A fuel above the grade required for your vehicle will actually have a hard time burning and that means WASTED FUEL.  Wasted fuel of course is bad for your wallet, bad for the environment, but most importantly bad for your Catalytic Converter(s).

” I like to use premium now and then to clean my engine”

This claim is completely baseless.  If this person knew anything about fuel, he’d know just how stupid this statement is.  As i said before, using premium when your engine requires regular will have nothing but have negative effects.  If by “Cleaning his engine” he meant sending more unburnt or incompletely burnt fuel down his tail pipe(s), then he indeed is correct.  Using premium when a lower grade is required will not make your engine burn hotter, burn cleaner, or have more horsepower.

“Premium is too expensive, im just gonna use regular from now on.  How bad can it be?”

If you’ve said this, you should not be driving a high performance/ luxury/ turbo vehicle.  Using regular in a vehicle that requires premium can have all kinds of detrimental effects.  As i said above, using too low of an octane fuel can result in misfires, pre-ignition, and increased engine wear.  Your car has computers that will try to adjust fuel usage to prevent misfires or pre-igntion, but guess what its fix will be?  If you answered: “Dump fuel into the cylinders to protect them.”, you are correct.  Your car will actually try send way more fuel into the combustion chamber to prevent overheating,  early ignition, or misfire.  This means much lower fuel economy, and more fill ups.  Are you really saving more money? No, just buy the premium or sell the car.

QUICK TIPS:

- Use the only fuel required for your vehicle.

- Fill up in the morning.  The ground will be cooler and thus the fuel your putting into your tank will be more dense.  More fuel for your money.

- NEVER use Mid-Grade Fuel.  Your wasting your money.

- If your getting lower gas mileage even though your putting in the same fuel, don’t discount the gas station right away.  You might need some routine vehicle maintenance. (New Air Filter, Fuel Filter, ect…)

Thanks for reading. Part 2 is coming soon.  Lots more to learn about that stuff your putting into your tank, and where you get it from!  Feel free to comment below!

- Tim (The Bimmer Mechanic)

Welcome!

Hello!

Welcome and thank you for stopping by my blog.  In the near future this blog will be filled with BMW related news, maintenance tips, and general BMW talk.

Please check out my “About Tim” page if you’d like to know a little more about me.

This blog is in its infancy, but please  stay tuned and bear with me.  Do keep in mind i am a mechanic, not a professional blogger, so if i make mistakes please polietly point them out and i will get them fixed.

Thats all for now.  Welcome to the Blog!

- Tim